Mississippi Power (MSPWP) 10-K14 Feb 242023 FY Annual reportFinancial data

Company Profile

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
Cover Page - USD ($) $ in Billions	Dec. 31, 2023	Jan. 31, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-3526
Entity Registrant Name	The Southern Company
Entity Tax Identification Number	58-0690070
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	30 Ivan Allen Jr. Boulevard, N.W.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-5000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction	false
Entity Shell Company	false
Entity Public Float			$ 76.6
Entity Common Stock, Shares Outstanding (in shares)		1,091,015,113
Documents Incorporated by Reference	Documents incorporated by reference: specified portions of The Southern Company's Definitive Proxy Statement on Schedule 14A relating to the 2024 Annual Meeting of Stockholders are incorporated by reference into PART III. Each of Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas meets the conditions set forth in General Instructions I(1)(a) and (b) of Form 10-K and is therefore filing this Form 10-K with the reduced disclosure format specified in General Instructions I(2)(b), (c), and (d) of Form 10-K. This combined Form 10-K is separately filed by The Southern Company, Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants.
Entity Central Index Key	0000092122
Amendment Flag	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Common Stock, par value $5 per share
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $5 per share
Trading Symbol	SO
Security Exchange Name	NYSE
Series 2017B 5.25% Junior Subordinated Notes due 2077
Document Information [Line Items]
Title of 12(b) Security	Series 2017B 5.25% Junior Subordinated Notes due 2077
Trading Symbol	SOJC
Security Exchange Name	NYSE
Series 2020A 4.95% Junior Subordinated Notes due 2080
Document Information [Line Items]
Title of 12(b) Security	Series 2020A 4.95% Junior Subordinated Notes due 2080
Trading Symbol	SOJD
Security Exchange Name	NYSE
Series 2020C 4.20% Junior Subordinated Notes due 2060
Document Information [Line Items]
Title of 12(b) Security	Series 2020C 4.20% Junior Subordinated Notes due 2060
Trading Symbol	SOJE
Security Exchange Name	NYSE
Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081
Document Information [Line Items]
Title of 12(b) Security	Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081
Trading Symbol	SO 81
Security Exchange Name	NYSE
Alabama Power
Document Information [Line Items]
Entity File Number	1-3164
Entity Registrant Name	Alabama Power Company
Entity Tax Identification Number	63-0004250
Entity Incorporation, State or Country Code	AL
Entity Address, Address Line One	600 North 18th Street
Entity Address, City or Town	Birmingham
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	35203
City Area Code	205
Local Phone Number	257-1000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		30,537,500
Entity Central Index Key	0000003153
Georgia Power
Document Information [Line Items]
Entity File Number	1-6468
Entity Registrant Name	Georgia Power Company
Entity Tax Identification Number	58-0257110
Entity Incorporation, State or Country Code	GA
Entity Address, Address Line One	241 Ralph McGill Boulevard, N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-6526
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		9,261,500
Entity Central Index Key	0000041091
Georgia Power \| Series 2017A 5.00% Junior Subordinated Notes due 2077
Document Information [Line Items]
Title of 12(b) Security	Series 2017A 5.00% Junior Subordinated Notes due 2077
Trading Symbol	GPJA
Security Exchange Name	NYSE
Mississippi Power
Document Information [Line Items]
Entity File Number	001-11229
Entity Registrant Name	Mississippi Power Company
Entity Tax Identification Number	64-0205820
Entity Incorporation, State or Country Code	MS
Entity Address, Address Line One	2992 West Beach Boulevard
Entity Address, City or Town	Gulfport
Entity Address, State or Province	MS
Entity Address, Postal Zip Code	39501
City Area Code	228
Local Phone Number	864-1211
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		1,121,000
Entity Central Index Key	0000066904
Southern Power
Document Information [Line Items]
Entity File Number	001-37803
Entity Registrant Name	Southern Power Company
Entity Tax Identification Number	58-2598670
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	30 Ivan Allen Jr. Boulevard, N.W.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-5000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		1,000
Entity Central Index Key	0001160661
Southern Power \| Series 2016B 1.850% Senior Notes due 2026
Document Information [Line Items]
Title of 12(b) Security	Series 2016B 1.850% Senior Notes due 2026
Trading Symbol	SO/26A
Security Exchange Name	NYSE
Southern Company Gas
Document Information [Line Items]
Entity File Number	1-14174
Entity Registrant Name	Southern Company Gas
Entity Tax Identification Number	58-2210952
Entity Incorporation, State or Country Code	GA
Entity Address, Address Line One	Ten Peachtree Place, N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30309
City Area Code	404
Local Phone Number	584-4000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		100
Entity Central Index Key	0001004155

Audit Information

Audit Information	12 Months Ended
Audit Information	Dec. 31, 2023
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Alabama Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Birmingham, Alabama
Georgia Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Mississippi Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Company Gas
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Natural Gas Company, LLC
Auditor [Line Items]
Auditor Name	BDO USA, P.C.
Auditor Firm ID	243
Auditor Location	Houston, Texas

Consolidated Statements of Inco

Consolidated Statements of Income - Southern - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Impairment charges	0	251	2
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Allowance for equity funds used during construction	268	224	190
Earnings from equity method investments	144	151	76
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes (benefit)	496	795	267
Net Income	3,849	3,428	2,309
Dividends on preferred stock of subsidiaries	0	11	15
Net loss attributable to noncontrolling interests	(127)	(107)	(99)
Consolidated Net Income	$ 3,976	$ 3,524	$ 2,393
Earnings per share —
Basic (in dollars per share)	$ 3.64	$ 3.28	$ 2.26
Diluted (in dollars per share)	$ 3.62	$ 3.26	$ 2.24
Average number of shares of common stock outstanding — (in millions)
Basic (in shares)	1,092	1,075	1,061
Diluted (in shares)	1,098	1,081	1,068
Retail electric revenues
Operating Revenues:
Total operating revenues	$ 16,343	$ 18,197	$ 14,852
Wholesale electric revenues
Operating Revenues:
Total operating revenues	2,467	3,641	2,455
Other electric revenues
Operating Revenues:
Total operating revenues	792	747	718
Natural Gas
Operating Revenues:
Total operating revenues	4,702	5,962	4,380
Other revenues
Operating Revenues:
Total operating revenues	949	732	708
Operating Expenses:
Cost of sales	560	396	357
Fuel
Operating Expenses:
Cost of sales	4,365	6,835	4,010
Purchased power
Operating Expenses:
Cost of sales	883	1,593	978
Natural gas
Operating Expenses:
Cost of sales	$ 1,644	$ 3,004	$ 1,619

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - Southern - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Changes in fair value, net of tax	(41)	(60)	(49)
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(39)	48	98
Reclassification adjustment for amounts included in net income, net of tax	1	10	13
Total other comprehensive income (loss)	(10)	71	158
Dividends on preferred stock of subsidiaries	0	11	15
Comprehensive loss attributable to noncontrolling interests	(127)	(107)	(99)
Comprehensive Income	$ 3,966	$ 3,595	$ 2,551

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income - Southern (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Qualifying hedges, change in fair value, tax	$ (17)	$ (19)	$ (16)
Qualifying hedges, reclassification adjustment, tax	27	23	31
Pension and other postretirement benefit plans, gain (loss), tax	(14)	18	37
Reclassification adjustment for amounts included in net income, tax	$ 0	$ 3	$ 5

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - Southern - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Consolidated net income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Utilization of federal investment tax credits	353	88	288
Allowance for equity funds used during construction	(268)	(224)	(190)
Pension, postretirement, and other employee benefits	(527)	(436)	(305)
Settlement of asset retirement obligations	(617)	(455)	(456)
Storm damage and reliability reserve accruals	124	430	288
Stock based compensation expense	137	127	144
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Impairment charges	0	251	91
Retail fuel cost under recovery – long-term	(206)	(2,166)	(536)
Natural gas cost under recovery – long-term	0	207	(207)
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Retail fuel cost under recovery	686	(100)	(4)
-Fossil fuel for generation	(368)	(125)	99
-Materials and supplies	(345)	(160)	(130)
-Natural gas cost under recovery	108	158	(266)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Customer refunds	(157)	119	130
-Natural gas cost over recovery	214	0	0
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Nuclear decommissioning trust fund purchases	(1,142)	(1,125)	(1,598)
Nuclear decommissioning trust fund sales	1,121	1,112	1,593
Proceeds from dispositions	164	275	917
Cost of removal, net of salvage	(592)	(649)	(442)
Change in construction payables, net	18	203	(124)
Payments pursuant to LTSAs	(99)	(190)	(188)
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase (decrease) in notes payable, net	973		530
Increase (decrease) in notes payable, net		(337)
Proceeds —
Long-term debt	8,972	5,132	8,262
Short-term borrowings	350	2,650	325
Common stock	36	1,808	73
Redemptions and repurchases —
Long-term debt	(4,294)	(2,158)	(4,327)
Short-term borrowings	(1,630)	(1,150)	(25)
Preferred stock	0	(298)	0
Capital contributions from noncontrolling interests	21	73	501
Distributions to noncontrolling interests	(234)	(259)	(351)
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
LTSA credits utilized from the sale of spare parts	23	0	0
Contributions from noncontrolling interests	0	15	89
Contributions of wind turbine equipment	$ 0	$ 0	$ 82

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows - Southern (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Cash Flows [Abstract]
Net cash paid for capitalized interest	$ 132	$ 103	$ 92

Consolidated Balance Sheets - S

Consolidated Balance Sheets - Southern - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts	2,030	2,128
Unbilled revenues	786	1,012
Under recovered fuel clause revenues	696	10
Other accounts and notes	519	637
Accumulated provision for uncollectible accounts	(68)	(71)
Materials and supplies	1,989	1,664
Fossil fuel for generation	943	575
Natural gas for sale	420	438
Prepaid expenses	406	347
Assets from risk management activities, net of collateral	36	115
Regulatory assets – asset retirement obligations	274	332
Natural gas cost under recovery	0	108
Other regulatory assets	1,120	860
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Other utility plant, net	499	599
Nuclear fuel, at amortized cost	858	843
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Goodwill	5,161	5,161
Nuclear decommissioning trusts, at fair value	2,424	2,145
Equity investments in unconsolidated subsidiaries	1,368	1,443
Other intangible assets, net of amortization	368	406
Miscellaneous property and investments	665	602
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,432	1,531
Deferred charges related to income taxes	886	866
Prepaid pension costs	2,079	2,290
Unamortized loss on reacquired debt	220	238
Deferred under recovered retail fuel clause revenues	1,261	2,056
Regulatory assets – asset retirement obligations, deferred	5,459	5,764
Other regulatory assets, deferred	6,264	5,918
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Notes payable	2,314	2,609
Accounts payable	2,898	3,525
Customer deposits	503	502
Accrued taxes —
Accrued income taxes	8	60
Other accrued taxes	860	764
Accrued interest	652	614
Accrued compensation	1,151	1,127
Asset retirement obligations	744	694
Liabilities from risk management activities, net of collateral	294	178
Operating lease obligations	183	197
Natural gas cost over recovery	214	0
Other regulatory liabilities	141	382
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Deferred credits related to income taxes	4,674	5,235
Accumulated deferred ITCs	2,067	2,133
Employee benefit obligations	1,115	1,238
Operating lease obligations, deferred	1,307	1,388
Asset retirement obligations, deferred	9,573	10,146
Other cost of removal obligations	1,957	1,903
Other regulatory liabilities, deferred	715	733
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Common stock	5,423	5,417
Paid-in capital	13,775	13,673
Treasury, at cost	(59)	(53)
Retained earnings	12,482	11,538
Accumulated other comprehensive loss	(177)	(167)
Total common stockholders' equity	31,444	30,408
Noncontrolling Interests	3,781	4,124
Total stockholders' equity	35,225	34,532
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters

Consolidated Balance Sheets -_2

Consolidated Balance Sheets - Southern (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Other intangible assets, amortization	$ 376	$ 340
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Common stock, shares issued (in shares)	1,100,000,000	1,100,000,000
Treasury stock (in shares)	1,000,000	1,000,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - Southern - USD ($) $ in Millions	Total	Common Stock	Treasury	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)			(1,000,000)
Beginning balance (in shares) at Dec. 31, 2020		1,058,000,000
Beginning balance at Dec. 31, 2020	$ 32,234	$ 5,268	$ (46)	$ 11,834	$ 11,311	$ (395)	$ 4,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	2,294				2,393		(99)
Other comprehensive income (loss)	158					158
Stock issued (in shares)		3,000,000
Stock issued	73	$ 11		62
Stock-based compensation	62			62
Cash dividends on common stock	(2,777)				(2,777)
Capital contributions from noncontrolling interests	590						590
Distributions to noncontrolling interests	(351)						(351)
Other	(7)		(1)	(8)	2
Ending balance (in shares) at Dec. 31, 2021		1,061,000,000
Ending balance at Dec. 31, 2021	32,276	$ 5,279	$ (47)	11,950	10,929	(237)	4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)			(1,000,000)
Consolidated net income (loss)	3,417				3,524		(107)
Other comprehensive income (loss)	71					71
Stock issued (in shares)		29,000,000
Stock issued	1,808	$ 138		1,670
Stock-based compensation	44			44
Cash dividends on common stock	(2,907)				(2,907)
Capital contributions from noncontrolling interests	88						88
Distributions to noncontrolling interests	(259)						(259)
Other	(6)		$ (6)	9	(8)	(1)
Ending balance (in shares) at Dec. 31, 2022		1,090,000,000
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ (53)	13,673	11,538	(167)	4,124
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	(1,000,000)		(1,000,000)
Consolidated net income (loss)	$ 3,849				3,976		(127)
Other comprehensive income (loss)	(10)					(10)
Stock issued (in shares)		2,000,000
Stock issued	36	$ 6		30
Stock-based compensation	73			73
Cash dividends on common stock	(3,035)				(3,035)
Capital contributions from noncontrolling interests	21						21
Distributions to noncontrolling interests	(236)						(236)
Other	(5)		$ (6)	(1)	3		(1)
Ending balance (in shares) at Dec. 31, 2023		1,092,000,000
Ending balance at Dec. 31, 2023	$ 35,225	$ 5,423	$ (59)	$ 13,775	$ 12,482	$ (177)	$ 3,781
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance (in shares)	(1,000,000)		(1,000,000)

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity - Southern (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 2.7800	$ 2.7000	$ 2.6200

Statements of Income - APC

Statements of Income - APC - USD ($) $ in Millions	12 Months Ended
Statements of Income - APC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Allowance for equity funds used during construction	268	224	190
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes	496	795	267
Net Income	3,849	3,428	2,309
Dividends on Preferred Stock	0	11	15
Consolidated Net Income	3,976	3,524	2,393
Retail electric revenues
Operating Revenues:
Total operating revenues	16,343	18,197	14,852
Other revenues
Operating Revenues:
Total operating revenues	949	732	708
Operating Expenses:
Cost of sales	560	396	357
Fuel
Operating Expenses:
Cost of sales	4,365	6,835	4,010
Purchased power
Operating Expenses:
Cost of sales	883	1,593	978
Alabama Power
Operating Revenues:
Total operating revenues	7,050	7,817	6,413
Operating Expenses:
Other operations and maintenance	1,769	1,935	1,735
Depreciation and amortization	1,401	875	859
Taxes other than income taxes	442	424	410
Total operating expenses	5,415	5,875	4,607
Operating Income	1,635	1,942	1,806
Other Income and (Expense):
Allowance for equity funds used during construction	82	70	52
Interest expense, net of amounts capitalized	(425)	(382)	(340)
Other income (expense), net	159	144	107
Total other income and (expense)	(184)	(168)	(181)
Earnings Before Income Taxes	1,451	1,774	1,625
Income taxes	81	423	372
Net Income	1,370	1,351	1,253
Dividends on Preferred Stock	0	11	15
Consolidated Net Income	1,370	1,340	1,238
Alabama Power \| Retail electric revenues
Operating Revenues:
Total operating revenues	6,159	6,470	5,499
Alabama Power \| Wholesale revenues
Operating Revenues:
Total operating revenues	424	726	377
Alabama Power \| Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	60	202	171
Alabama Power \| Other revenues
Operating Revenues:
Total operating revenues	407	419	366
Alabama Power \| Fuel
Operating Expenses:
Cost of sales	1,299	1,840	1,235
Alabama Power \| Purchased power
Operating Expenses:
Cost of sales	253	441	221
Alabama Power \| Purchased power, affiliates
Operating Expenses:
Cost of sales	$ 251	$ 360	$ 147

Statements of Comprehensive Inc

Statements of Comprehensive Income - APC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Changes in fair value, net of tax	(41)	(60)	(49)
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Total other comprehensive income (loss)	(10)	71	158
Comprehensive Income	3,966	3,595	2,551
Alabama Power
Net Income	1,370	1,351	1,253
Qualifying hedges:
Changes in fair value, net of tax	0	(1)	2
Reclassification adjustment for amounts included in net income, net of tax	2	5	4
Total other comprehensive income (loss)	2	4	6
Comprehensive Income	$ 1,372	$ 1,355	$ 1,259

Statements of Comprehensive I_2

Statements of Comprehensive Income - APC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualifying hedges, change in fair value, tax	$ (17)	$ (19)	$ (16)
Qualifying hedges, reclassification adjustment, tax	27	23	31
Alabama Power
Qualifying hedges, change in fair value, tax	0	0	1
Qualifying hedges, reclassification adjustment, tax	$ 1	$ 2	$ 2

Statements of Cash Flows - APC

Statements of Cash Flows - APC - USD ($) $ in Millions	12 Months Ended
Statements of Cash Flows - APC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net Income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Allowance for equity funds used during construction	(268)	(224)	(190)
Pension, postretirement, and other employee benefits	(527)	(436)	(305)
Settlement of asset retirement obligations	(617)	(455)	(456)
Natural disaster reserve and reliability reserve accruals	124	430	288
Retail fuel cost under recovery – long-term	(206)	(2,166)	(536)
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Fossil fuel stock	(368)	(125)	99
-Materials and supplies	(345)	(160)	(130)
-Retail fuel cost under recovery	686	(100)	(4)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Customer refunds	(157)	119	130
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Nuclear decommissioning trust fund purchases	(1,142)	(1,125)	(1,598)
Nuclear decommissioning trust fund sales	1,121	1,112	1,593
Cost of removal, net of salvage	(592)	(649)	(442)
Change in construction payables, net	18	203	(124)
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase in notes payable, net	973		530
Redemptions and repurchases —
Preferred stock	0	(298)	0
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
Alabama Power
Operating Activities:
Net Income	1,370	1,351	1,253
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	1,554	1,014	1,005
Deferred income taxes	(242)	355	245
Allowance for equity funds used during construction	(82)	(70)	(52)
Pension, postretirement, and other employee benefits	(204)	(118)	(106)
Settlement of asset retirement obligations	(270)	(205)	(202)
Natural disaster reserve and reliability reserve accruals	70	185	75
Retail fuel cost under recovery – long-term	0	(520)	(126)
Other, net	4	(50)	(53)
Changes in certain current assets and liabilities —
-Receivables	(24)	(321)	42
-Fossil fuel stock	(165)	(70)	76
-Materials and supplies	(105)	(7)	(6)
-Retail fuel cost under recovery	376	(102)	0
-Other current assets	(20)	(23)	(31)
-Accounts payable	(162)	249	(109)
-Customer refunds	(39)	5	128
-Other current liabilities	18	(34)	(86)
Net cash provided from operating activities	2,079	1,639	2,053
Investing Activities:
Property additions	(2,022)	(2,016)	(1,753)
Nuclear decommissioning trust fund purchases	(301)	(355)	(638)
Nuclear decommissioning trust fund sales	300	354	637
Cost of removal, net of salvage	(178)	(234)	(165)
Change in construction payables, net	(44)	50	(16)
Other investing activities	49	(62)	(26)
Net cash used for investing activities	(2,196)	(2,263)	(1,961)
Financing Activities:
Increase in notes payable, net	40	0	0
Proceeds —
Senior notes	500	1,700	1,300
Revenue bonds	326	0	0
Other long-term debt	29	0	0
Redemptions and repurchases —
Senior notes	(300)	(750)	(200)
Preferred stock	0	(298)	0
Revenue bonds	0	0	(65)
Other long-term debt	0	0	(206)
Capital contributions from parent company	407	649	636
Payment of common stock dividends	(1,141)	(1,016)	(984)
Other financing activities	(22)	(34)	(43)
Net cash provided from financing activities	(161)	251	438
Net Change in Cash, Cash Equivalents, and Restricted Cash	(278)	(373)	530
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	687	1,060	530
Cash, Cash Equivalents, and Restricted Cash at End of Year	409	687	1,060
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	397	342	308
Income taxes, net	315	121	185
Noncash transactions —
Accrued property additions at year-end	$ 138	$ 182	$ 150

Statements of Cash Flows - APC

Statements of Cash Flows - APC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net cash paid for capitalized interest	$ 132	$ 103	$ 92
Alabama Power
Net cash paid for capitalized interest	$ 27	$ 20	$ 15

Balance Sheets - APC

Balance Sheets - APC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts and affiliated	2,030	2,128
Unbilled revenues	786	1,012
Other accounts and notes	519	637
Accumulated provision for uncollectible accounts	(68)	(71)
Fossil fuel stock	943	575
Materials and supplies	1,989	1,664
Prepaid expenses	406	347
Other regulatory assets	1,120	860
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated provision for depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Other utility plant, net	499	599
Nuclear fuel, at amortized cost	858	843
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,424	2,145
Equity investments in unconsolidated subsidiaries	1,368	1,443
Miscellaneous property and investments	665	602
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,432	1,531
Deferred charges related to income taxes	886	866
Regulatory assets – asset retirement obligations	5,459	5,764
Other regulatory assets, deferred	6,264	5,918
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Notes payable	2,314	2,609
Accounts payable —
Customer deposits	503	502
Accrued interest	652	614
Accrued compensation	1,151	1,127
Asset retirement obligations	744	694
Other regulatory liabilities	141	382
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Deferred credits related to income taxes	4,674	5,235
Accumulated deferred ITCs	2,067	2,133
Employee benefit obligations	1,115	1,238
Operating lease obligations	1,307	1,388
Asset retirement obligations, deferred	9,573	10,146
Other regulatory liabilities, deferred	715	733
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Common stock	5,423	5,417
Paid-in capital	13,775	13,673
Retained earnings	12,482	11,538
Accumulated other comprehensive loss	(177)	(167)
Total common stockholders' equity	31,444	30,408
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters
Alabama Power
Current Assets:
Cash and cash equivalents	324	687
Receivables —
Customer accounts and affiliated	513	431
Unbilled revenues	191	174
Other accounts and notes	109	153
Accumulated provision for uncollectible accounts	(16)	(14)
Fossil fuel stock	394	229
Materials and supplies	655	557
Prepaid expenses	62	65
Regulatory assets – under recovered retail fuel clause revenues	246	102
Other regulatory assets	385	372
Other current assets	142	67
Total current assets	3,077	2,924
Property, Plant, and Equipment:
In service	35,429	33,472
Less: Accumulated provision for depreciation	11,131	10,470
Plant in service, net of depreciation	24,298	23,002
Other utility plant, net	499	599
Nuclear fuel, at amortized cost	253	239
Construction work in progress	1,095	1,526
Total property, plant, and equipment	26,145	25,366
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,261	1,127
Equity investments in unconsolidated subsidiaries	52	57
Miscellaneous property and investments	155	124
Total other property and investments	1,468	1,308
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	87	71
Deferred charges related to income taxes	262	250
Prepaid pension and other postretirement benefit costs	659	657
Regulatory assets – asset retirement obligations	1,810	1,845
Other regulatory assets, deferred	1,858	2,107
Other deferred charges and assets	414	442
Total deferred charges and other assets	5,090	5,372
Total Assets	35,780	34,970
Current Liabilities:
Securities due within one year	223	301
Notes payable	40	0
Accounts payable —
Affiliated and other	630	641
Customer deposits	105	106
Accrued taxes	51	57
Accrued interest	122	120
Accrued compensation	222	229
Asset retirement obligations	346	330
Other regulatory liabilities	44	96
Other current liabilities	191	91
Total current liabilities	2,304	2,414
Long-Term Debt	10,960	10,329
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	4,170	3,981
Deferred credits related to income taxes	1,506	1,925
Accumulated deferred ITCs	74	81
Employee benefit obligations	155	145
Operating lease obligations	81	67
Asset retirement obligations, deferred	3,812	3,957
Other regulatory liabilities, deferred	291	315
Other deferred credits and liabilities	94	69
Total deferred credits and other liabilities	10,183	10,540
Total Liabilities	23,447	23,283
Common Stockholders' Equity:
Common stock	1,222	1,222
Paid-in capital	7,125	6,710
Retained earnings	3,993	3,764
Accumulated other comprehensive loss	(7)	(9)
Total common stockholders' equity	12,333	11,687
Total Liabilities and Stockholders' Equity	35,780	34,970
Commitments and Contingent Matters
Alabama Power \| Related Party
Receivables —
Customer accounts and affiliated	72	101
Accounts payable —
Affiliated and other	$ 330	$ 443

Balance Sheets - APC (Parenthet

Balance Sheets - APC (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Alabama Power
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 40	$ 40
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares outstanding (in shares)	31,000,000	31,000,000

Statements of Common Stockholde

Statements of Common Stockholders' Equity - APC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Alabama Power	Alabama Power Common Stock	Alabama Power Paid-In Capital	Alabama Power Retained Earnings	Alabama Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					31
Beginning balance at Dec. 31, 2020						$ 9,810	$ 1,222	$ 5,413	$ 3,194	$ (19)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock	$ 2,393					1,238			1,238
Capital contributions from parent company						643		643
Other comprehensive income (loss)	158				$ 158	6				6
Cash dividends on common stock	(2,777)			$ (2,777)		(984)			(984)
Other	(7)		$ (8)	2
Ending balance (in shares) at Dec. 31, 2021		1,061					31
Ending balance at Dec. 31, 2021						10,713	$ 1,222	6,056	3,448	(13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock	3,524					1,340			1,340
Capital contributions from parent company						654		654
Other comprehensive income (loss)	71				71	4				4
Cash dividends on common stock	(2,907)			(2,907)		(1,016)			(1,016)
Other	(6)		9	(8)	(1)	(8)			(8)
Ending balance (in shares) at Dec. 31, 2022		1,090					31
Ending balance at Dec. 31, 2022	30,408					11,687	$ 1,222	6,710	3,764	(9)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income after dividends on preferred stock	3,976					1,370			1,370
Capital contributions from parent company						415		415
Other comprehensive income (loss)	(10)				$ (10)	2				2
Cash dividends on common stock	(3,035)			(3,035)		(1,141)			(1,141)
Other	(5)		$ (1)	$ 3
Ending balance (in shares) at Dec. 31, 2023		1,092					31
Ending balance at Dec. 31, 2023	$ 31,444					$ 12,333	$ 1,222	$ 7,125	$ 3,993	$ (7)

Statements of Income - GPC

Statements of Income - GPC - USD ($) $ in Millions	12 Months Ended
Statements of Income - GPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Allowance for equity funds used during construction	268	224	190
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes (benefit)	496	795	267
Net Income	3,849	3,428	2,309
Retail electric revenues
Operating Revenues:
Total operating revenues	16,343	18,197	14,852
Other revenues
Operating Revenues:
Total operating revenues	949	732	708
Operating Expenses:
Cost of sales	560	396	357
Fuel
Operating Expenses:
Cost of sales	4,365	6,835	4,010
Purchased power, non-affiliates
Operating Expenses:
Cost of sales	883	1,593	978
Georgia Power
Operating Revenues:
Total operating revenues	10,118	11,584	9,260
Operating Expenses:
Other operations and maintenance	2,083	2,349	2,213
Depreciation and amortization	1,681	1,430	1,371
Taxes other than income taxes	541	527	476
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Total operating expenses	7,299	9,232	8,692
Operating Income	2,819	2,352	568
Other Income and (Expense):
Allowance for equity funds used during construction	165	140	127
Interest expense, net of amounts capitalized	(626)	(485)	(421)
Other income (expense), net	170	176	142
Total other income and (expense)	(291)	(169)	(152)
Earnings Before Income Taxes	2,528	2,183	416
Income taxes (benefit)	448	370	(168)
Net Income	2,080	1,813	584
Georgia Power \| Retail electric revenues
Operating Revenues:
Total operating revenues	9,222	10,792	8,478
Georgia Power \| Wholesale revenues
Operating Revenues:
Total operating revenues	188	235	197
Georgia Power \| Other revenues
Operating Revenues:
Total operating revenues	708	557	585
Georgia Power \| Fuel
Operating Expenses:
Cost of sales	1,781	2,486	1,449
Georgia Power \| Purchased power, non-affiliates
Operating Expenses:
Cost of sales	517	856	632
Georgia Power \| Purchased power, affiliates
Operating Expenses:
Cost of sales	$ 764	$ 1,401	$ 859

Statements of Comprehensive I_3

Statements of Comprehensive Income - GPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Changes in fair value, net of tax	(41)	(60)	(49)
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Total other comprehensive income (loss)	(10)	71	158
Comprehensive Income	3,966	3,595	2,551
Georgia Power
Net Income	2,080	1,813	584
Qualifying hedges:
Changes in fair value, net of tax	(2)	23	0
Reclassification adjustment for amounts included in net income, net of tax	5	5	6
Total other comprehensive income (loss)	3	28	6
Comprehensive Income	$ 2,083	$ 1,841	$ 590

Statements of Comprehensive I_4

Statements of Comprehensive Income - GPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualifying hedges, change in fair value, tax	$ (17)	$ (19)	$ (16)
Qualifying hedges, reclassification adjustment, tax	27	23	31
Georgia Power
Qualifying hedges, change in fair value, tax	(1)	8	0
Qualifying hedges, reclassification adjustment, tax	$ 2	$ 2	$ 2

Statements of Cash Flows - GPC

Statements of Cash Flows - GPC - USD ($) $ in Millions	12 Months Ended
Statements of Cash Flows - GPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net Income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Allowance for equity funds used during construction	(268)	(224)	(190)
Pension, postretirement, and other employee benefits	(527)	(436)	(305)
Settlement of asset retirement obligations	(617)	(455)	(456)
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Retail fuel cost under recovery	686	(100)	(4)
-Fossil fuel stock	(368)	(125)	99
-Materials and supplies	(345)	(160)	(130)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Customer refunds	(157)	119	130
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Nuclear decommissioning trust fund purchases	(1,142)	(1,125)	(1,598)
Nuclear decommissioning trust fund sales	1,121	1,112	1,593
Cost of removal, net of salvage	(592)	(649)	(442)
Payments pursuant to LTSAs	(99)	(190)	(188)
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase (decrease) in notes payable, net	973		530
Increase (decrease) in notes payable, net		(337)
Proceeds —
Short-term borrowings	350	2,650	325
Redemptions and repurchases —
Short-term borrowings	(1,630)	(1,150)	(25)
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
Georgia Power
Operating Activities:
Net Income	2,080	1,813	584
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	1,914	1,622	1,557
Deferred income taxes	184	313	(550)
Allowance for equity funds used during construction	(165)	(140)	(127)
Pension, postretirement, and other employee benefits	(272)	(240)	(148)
Settlement of asset retirement obligations	(304)	(212)	(210)
Storm damage accruals	31	213	213
Retail fuel cost under recovery – long-term	(157)	(1,646)	(410)
Estimated loss on Plant Vogtle Units 3 and 4	(68)	183	1,692
Other, net	(82)	81	53
Changes in certain current assets and liabilities —
-Receivables	(57)	(286)	81
-Retail fuel cost under recovery	308	0	0
-Fossil fuel stock	(189)	(43)	30
-Materials and supplies	(154)	(73)	(82)
-Other current assets	(63)	(83)	(30)
-Accounts payable	(206)	264	186
-Accrued taxes	74	173	21
-Retail fuel cost over recovery	0	0	(113)
-Customer refunds	(117)	113	1
-Other current liabilities	(5)	(14)	(1)
Net cash provided from operating activities	2,752	2,038	2,747
Investing Activities:
Property additions	(4,786)	(3,809)	(3,311)
Nuclear decommissioning trust fund purchases	(841)	(770)	(960)
Nuclear decommissioning trust fund sales	821	758	956
Cost of removal, net of salvage	(279)	(274)	(149)
Change in construction payables, net of joint owner portion	50	186	(65)
Payments pursuant to LTSAs	(49)	(44)	(42)
Proceeds from dispositions	59	56	8
Other investing activities	(54)	(57)	(27)
Net cash used for investing activities	(5,079)	(3,954)	(3,590)
Financing Activities:
Increase (decrease) in notes payable, net	811
Increase (decrease) in notes payable, net		0	(60)
Proceeds —
Senior notes	2,450	1,500	750
Short-term borrowings	350	2,100	0
FFB loan	0	0	440
Revenue bonds	229	200	122
Redemptions and repurchases —
Senior notes	(800)	(400)	(325)
Short-term borrowings	(1,430)	(500)	0
FFB loan	(86)	(88)	(96)
Revenue bonds	0	(53)	(69)
Other long-term debt	0	(125)	0
Capital contributions from parent company	2,291	1,471	1,782
Payment of common stock dividends	(1,855)	(1,691)	(1,649)
Other financing activities	(38)	(51)	(28)
Net cash provided from financing activities	1,922	2,363	867
Net Change in Cash, Cash Equivalents, and Restricted Cash	(405)	447	24
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	480	33	9
Cash, Cash Equivalents, and Restricted Cash at End of Year	75	480	33
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	592	432	382
Income taxes, net	220	30	305
Noncash transactions —
Accrued property additions at year-end	$ 680	$ 626	$ 479

Statements of Cash Flows - GPC

Statements of Cash Flows - GPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net cash paid for capitalized interest	$ 132	$ 103	$ 92
Georgia Power
Net cash paid for capitalized interest	$ 86	$ 73	$ 63

Balance Sheets - GPC

Balance Sheets - GPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts, net and affiliated	2,030	2,128
Unbilled revenues	786	1,012
Under recovered fuel clause revenues	696	10
Other accounts and notes	519	637
Fossil fuel stock	943	575
Materials and supplies	1,989	1,664
Regulatory assets – asset retirement obligations	274	332
Other regulatory assets	1,120	860
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated provision for depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Nuclear fuel, at amortized cost	858	843
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,424	2,145
Equity investments in unconsolidated subsidiaries	1,368	1,443
Miscellaneous property and investments	665	602
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,432	1,531
Deferred charges related to income taxes	886	866
Prepaid pension costs	2,079	2,290
Deferred under recovered retail fuel clause revenues	1,261	2,056
Regulatory assets – asset retirement obligations, deferred	5,459	5,764
Other regulatory assets, deferred	6,264	5,918
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Notes payable	2,314	2,609
Accounts payable —
Customer deposits	503	502
Accrued interest	652	614
Accrued compensation	1,151	1,127
Operating lease obligations	183	197
Asset retirement obligations	744	694
Other regulatory liabilities	141	382
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Deferred credits related to income taxes	4,674	5,235
Accumulated deferred ITCs	2,067	2,133
Employee benefit obligations	1,115	1,238
Operating lease obligations, deferred	1,307	1,388
Asset retirement obligations, deferred	9,573	10,146
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Common stock	5,423	5,417
Paid-in capital	13,775	13,673
Retained earnings	12,482	11,538
Accumulated other comprehensive loss	(177)	(167)
Total common stockholders' equity	31,444	30,408
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters
Georgia Power
Current Assets:
Cash and cash equivalents	9	364
Receivables —
Customer accounts, net and affiliated	843	735
Unbilled revenues	275	309
Under recovered fuel clause revenues	694	0
Joint owner accounts	119	128
Other accounts and notes	81	62
Fossil fuel stock	480	291
Materials and supplies	883	729
Regulatory assets – asset retirement obligations	98	158
Other regulatory assets	423	324
Other current assets	305	246
Total current assets	4,261	3,399
Property, Plant, and Equipment:
In service	49,370	41,879
Less: Accumulated provision for depreciation	13,955	13,115
Plant in service, net of depreciation	35,415	28,764
Nuclear fuel, at amortized cost	605	604
Construction work in progress	4,975	8,103
Total property, plant, and equipment	40,995	37,471
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,163	1,018
Equity investments in unconsolidated subsidiaries	47	51
Miscellaneous property and investments	151	107
Total other property and investments	1,361	1,176
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	884	1,007
Deferred charges related to income taxes	594	583
Prepaid pension costs	706	738
Deferred under recovered retail fuel clause revenues	1,211	2,056
Regulatory assets – asset retirement obligations, deferred	3,407	3,671
Other regulatory assets, deferred	2,890	2,522
Other deferred charges and assets	508	540
Total deferred charges and other assets	10,200	11,117
Total Assets	56,817	53,163
Current Liabilities:
Securities due within one year	502	901
Notes payable	1,329	1,600
Accounts payable —
Affiliated and other	1,147	1,076
Customer deposits	250	252
Accrued taxes	582	508
Accrued interest	175	157
Accrued compensation	250	254
Operating lease obligations	135	151
Asset retirement obligations	338	295
Other regulatory liabilities	22	170
Other current liabilities	365	286
Total current liabilities	5,935	6,578
Long-Term Debt	16,198	14,009
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	4,018	3,707
Deferred credits related to income taxes	2,161	2,244
Accumulated deferred ITCs	326	319
Employee benefit obligations	248	318
Operating lease obligations, deferred	740	851
Asset retirement obligations, deferred	5,327	5,739
Other deferred credits and liabilities	481	540
Total deferred credits and other liabilities	13,301	13,718
Total Liabilities	35,434	34,305
Common Stockholders' Equity:
Common stock	398	398
Paid-in capital	17,923	15,626
Retained earnings	3,071	2,846
Accumulated other comprehensive loss	(9)	(12)
Total common stockholders' equity	21,383	18,858
Total Liabilities and Stockholders' Equity	56,817	53,163
Commitments and Contingent Matters
Georgia Power \| Related Party
Receivables —
Customer accounts, net and affiliated	51	53
Accounts payable —
Affiliated and other	$ 840	$ 928

Balance Sheets - GPC (Parenthet

Balance Sheets - GPC (Parenthetical) - shares	Dec. 31, 2023	Dec. 31, 2022
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Georgia Power
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares outstanding (in shares)	9,000,000	9,000,000

Statements of Common Stockhol_2

Statements of Common Stockholders' Equity - GPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Georgia Power	Georgia Power Common Stock	Georgia Power Paid-In Capital	Georgia Power Retained Earnings	Georgia Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					9
Beginning balance at Dec. 31, 2020						$ 16,501	$ 398	$ 12,361	$ 3,789	$ (47)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 2,309					584			584
Capital contributions from parent company						1,792		1,792
Other comprehensive income	158				$ 158	6				6
Cash dividends on common stock	(2,777)			$ (2,777)		(1,649)			(1,649)
Other	(7)		$ (8)	2
Ending balance (in shares) at Dec. 31, 2021		1,061					9
Ending balance at Dec. 31, 2021						17,234	$ 398	14,153	2,724	(41)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,428					1,813			1,813
Capital contributions from parent company						1,473		1,473
Other comprehensive income	71				71	28				28
Cash dividends on common stock	(2,907)			(2,907)		(1,691)			(1,691)
Other	(6)		9	(8)	(1)	1			0	1
Ending balance (in shares) at Dec. 31, 2022		1,090					9
Ending balance at Dec. 31, 2022	30,408					18,858	$ 398	15,626	2,846	(12)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,849					2,080			2,080
Capital contributions from parent company						2,297		2,297
Other comprehensive income	(10)				$ (10)	3				3
Cash dividends on common stock	(3,035)			(3,035)		(1,855)			(1,855)
Other	(5)		$ (1)	$ 3
Ending balance (in shares) at Dec. 31, 2023		1,092					9
Ending balance at Dec. 31, 2023	$ 31,444					$ 21,383	$ 398	$ 17,923	$ 3,071	$ (9)

Statements of Income - MPC

Statements of Income - MPC - USD ($) $ in Millions	12 Months Ended
Statements of Income - MPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes	496	795	267
Net Income	3,849	3,428	2,309
Retail revenues
Operating Revenues:
Total operating revenues	16,343	18,197	14,852
Other revenues
Operating Revenues:
Total operating revenues	949	732	708
Operating Expenses:
Fuel and purchased power	560	396	357
Mississippi Power
Operating Revenues:
Total operating revenues	1,474	1,694	1,322
Operating Expenses:
Other operations and maintenance	362	376	313
Depreciation and amortization	190	181	180
Taxes other than income taxes	124	124	128
Total operating expenses	1,214	1,470	1,117
Operating Income	260	224	205
Other Income and (Expense):
Interest expense, net of amounts capitalized	(71)	(56)	(60)
Other income (expense), net	35	33	35
Total other income and (expense)	(36)	(23)	(25)
Earnings Before Income Taxes	224	201	180
Income taxes	36	37	21
Net Income	188	164	159
Mississippi Power \| Retail revenues
Operating Revenues:
Total operating revenues	963	935	875
Mississippi Power \| Wholesale revenues, non-affiliates
Operating Revenues:
Total operating revenues	272	252	230
Mississippi Power \| Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	200	460	188
Mississippi Power \| Other revenues
Operating Revenues:
Total operating revenues	39	47	29
Mississippi Power \| Fuel and purchased power
Operating Expenses:
Fuel and purchased power	$ 538	$ 789	$ 496

Statements of Comprehensive I_5

Statements of Comprehensive Income - MPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Total other comprehensive income (loss)	(10)	71	158
Comprehensive Income	3,966	3,595	2,551
Mississippi Power
Net Income	188	164	159
Qualifying hedges:
Reclassification adjustment for amounts included in net income, net of tax	0	0	1
Total other comprehensive income (loss)	0	0	1
Comprehensive Income	$ 188	$ 164	$ 160

Statements of Comprehensive I_6

Statements of Comprehensive Income - MPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualifying hedges, reclassification adjustment, tax	$ 27	$ 23	$ 31
Mississippi Power
Qualifying hedges, reclassification adjustment, tax	$ 0	$ 0	$ 0

Statements of Cash Flows - MPC

Statements of Cash Flows - MPC - USD ($) $ in Millions	12 Months Ended
Statements of Cash Flows - MPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net Income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Pension, postretirement, and other employee benefits	(527)	(436)	(305)
Settlement of asset retirement obligations	(617)	(455)	(456)
Retail fuel cost under recovery – long-term	(206)	(2,166)	(536)
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Materials and supplies	(345)	(160)	(130)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Cost of removal net of salvage	(592)	(649)	(442)
Payments pursuant to LTSAs	(99)	(190)	(188)
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase (decrease) in notes payable, net		(337)
Redemptions —
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
Mississippi Power
Operating Activities:
Net Income	188	164	159
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	232	223	213
Deferred income taxes	(13)	(6)	(4)
Pension, postretirement, and other employee benefits	(20)	(18)	(10)
Settlement of asset retirement obligations	(18)	(20)	(24)
System restoration rider and reliability reserve accruals	23	32	(2)
Retail fuel cost under recovery – long-term	(50)	0	0
Other, net	(5)	21	(21)
Changes in certain current assets and liabilities —
-Receivables	85	(82)	9
-Materials and supplies	(9)	(10)	(6)
-Other current assets	7	(15)	0
-Accounts payable	(81)	97	(35)
-Accrued taxes	(7)	5	6
-Retail fuel cost over recovery	27	0	(24)
-Other current liabilities	10	(8)	(15)
Net cash provided from operating activities	369	383	246
Investing Activities:
Property additions	(319)	(257)	(198)
Cost of removal net of salvage	(32)	(27)	(20)
Payments pursuant to LTSAs	(26)	(29)	(29)
Other investing activities	7	(4)	(10)
Net cash used for investing activities	(370)	(317)	(257)
Financing Activities:
Increase (decrease) in notes payable, net	0	0	(25)
Proceeds —
Senior notes	100	0	525
Revenue bonds	0	35	0
Redemptions —
Revenue bonds	0	0	(320)
Other long-term debt	0	0	(100)
Capital contributions from parent company	68	68	120
Payment of common stock dividends	(185)	(170)	(157)
Other financing activities	(3)	(1)	(10)
Net cash provided from financing activities	(20)	(68)	33
Net Change in Cash, Cash Equivalents, and Restricted Cash	(21)	(2)	22
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	59	61	39
Cash, Cash Equivalents, and Restricted Cash at End of Year	38	59	61
Supplemental Cash Flow Information:
Interest	66	55	58
Income taxes, net	52	33	16
Noncash transactions —
Accrued property additions at year-end	$ 34	$ 22	$ 25

Balance Sheets - MPC

Balance Sheets - MPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts, net and affiliated	2,030	2,128
Unbilled revenues	786	1,012
Other accounts and notes	519	637
Fossil fuel stock	943	575
Materials and supplies	1,989	1,664
Other regulatory assets	1,120	860
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Deferred charges related to income taxes	886	866
Prepaid pension costs	2,079	2,290
Deferred under recovered retail fuel clause revenues	1,261	2,056
Regulatory assets – asset retirement obligations	5,459	5,764
Other regulatory assets, deferred	6,264	5,918
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Accounts payable —
Accrued compensation	1,151	1,127
Asset retirement obligations	744	694
Other regulatory liabilities	141	382
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Deferred credits related to income taxes	4,674	5,235
Employee benefit obligations	1,115	1,238
Asset retirement obligations, deferred	9,573	10,146
Other cost of removal obligations	1,957	1,903
Other regulatory liabilities, deferred	715	733
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Common stock	5,423	5,417
Paid-in capital	13,775	13,673
Accumulated deficit	12,482	11,538
Total common stockholders' equity	31,444	30,408
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters
Mississippi Power
Current Assets:
Cash and cash equivalents	38	59
Receivables —
Customer accounts, net and affiliated	36	47
Unbilled revenues	40	47
Other accounts and notes	20	35
Fossil fuel stock	47	44
Materials and supplies	89	80
Other regulatory assets	56	72
Other current assets	10	38
Total current assets	365	504
Property, Plant, and Equipment:
In service	5,523	5,254
Less: Accumulated depreciation	1,792	1,689
Plant in service, net of depreciation	3,731	3,565
Construction work in progress	203	208
Total property, plant, and equipment	3,934	3,773
Other Property and Investments:
Total other property and investments	158	167
Deferred Charges and Other Assets:
Deferred charges related to income taxes	28	30
Prepaid pension costs	99	109
Regulatory assets – asset retirement obligations	244	239
Other regulatory assets, deferred	285	249
Accumulated deferred income taxes	96	107
Other deferred charges and assets	85	94
Total deferred charges and other assets	887	828
Total Assets	5,344	5,272
Current Liabilities:
Securities due within one year	201	1
Accounts payable —
Affiliated and other	73	106
Accrued taxes	117	124
Accrued compensation	43	37
Asset retirement obligations	29	37
Over recovered retail fuel clause revenues	27	0
Other regulatory liabilities	17	43
Other current liabilities	90	85
Total current liabilities	679	554
Long-Term Debt	1,443	1,544
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	469	466
Deferred credits related to income taxes	229	253
Employee benefit obligations	67	69
Asset retirement obligations, deferred	139	142
Other cost of removal obligations	186	196
Other regulatory liabilities, deferred	92	96
Other deferred credits and liabilities	37	21
Total deferred credits and other liabilities	1,219	1,243
Total Liabilities	3,341	3,341
Common Stockholders' Equity:
Common stock	38	38
Paid-in capital	4,721	4,652
Accumulated deficit	(2,756)	(2,759)
Total common stockholders' equity	2,003	1,931
Total Liabilities and Stockholders' Equity	5,344	5,272
Commitments and Contingent Matters
Mississippi Power \| Related Party
Receivables —
Customer accounts, net and affiliated	29	82
Accounts payable —
Affiliated and other	82	121
Alabama Power
Current Assets:
Cash and cash equivalents	324	687
Receivables —
Customer accounts, net and affiliated	513	431
Unbilled revenues	191	174
Other accounts and notes	109	153
Fossil fuel stock	394	229
Materials and supplies	655	557
Other regulatory assets	385	372
Other current assets	142	67
Total current assets	3,077	2,924
Property, Plant, and Equipment:
In service	35,429	33,472
Less: Accumulated depreciation	11,131	10,470
Plant in service, net of depreciation	24,298	23,002
Construction work in progress	1,095	1,526
Total property, plant, and equipment	26,145	25,366
Other Property and Investments:
Total other property and investments	1,468	1,308
Deferred Charges and Other Assets:
Deferred charges related to income taxes	262	250
Deferred under recovered retail fuel clause revenues	50	0
Regulatory assets – asset retirement obligations	1,810	1,845
Other regulatory assets, deferred	1,858	2,107
Other deferred charges and assets	414	442
Total deferred charges and other assets	5,090	5,372
Total Assets	35,780	34,970
Current Liabilities:
Securities due within one year	223	301
Accounts payable —
Affiliated and other	630	641
Accrued taxes	51	57
Accrued compensation	222	229
Asset retirement obligations	346	330
Other regulatory liabilities	44	96
Other current liabilities	191	91
Total current liabilities	2,304	2,414
Long-Term Debt	10,960	10,329
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	4,170	3,981
Deferred credits related to income taxes	1,506	1,925
Employee benefit obligations	155	145
Asset retirement obligations, deferred	3,812	3,957
Other regulatory liabilities, deferred	291	315
Other deferred credits and liabilities	94	69
Total deferred credits and other liabilities	10,183	10,540
Total Liabilities	23,447	23,283
Common Stockholders' Equity:
Common stock	1,222	1,222
Paid-in capital	7,125	6,710
Accumulated deficit	3,993	3,764
Total common stockholders' equity	12,333	11,687
Total Liabilities and Stockholders' Equity	35,780	34,970
Commitments and Contingent Matters
Alabama Power \| Related Party
Receivables —
Customer accounts, net and affiliated	72	101
Accounts payable —
Affiliated and other	$ 330	$ 443

Balance Sheets - MPC (Parenthet

Balance Sheets - MPC (Parenthetical) - shares	Dec. 31, 2023	Dec. 31, 2022
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Mississippi Power
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares outstanding (in shares)	1,000,000	1,000,000

Statements of Common Stockhol_3

Statements of Common Stockholders' Equity - MPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Mississippi Power	Mississippi Power Common Stock	Mississippi Power Paid-In Capital	Mississippi Power Retained Earnings	Mississippi Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					1
Beginning balance at Dec. 31, 2020						$ 1,742	$ 38	$ 4,460	$ (2,754)	$ (2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 2,393					159			159
Capital contributions from parent company						122		122
Other comprehensive income (loss)	158				$ 158	1				1
Cash dividends on common stock	(2,777)			$ (2,777)		(157)			(157)
Other	(7)		$ (8)	2					(1)	1
Ending balance (in shares) at Dec. 31, 2021		1,061					1
Ending balance at Dec. 31, 2021						1,867	$ 38	4,582	(2,753)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,524					164			164
Capital contributions from parent company						70		70
Other comprehensive income (loss)	71				71
Cash dividends on common stock	(2,907)			(2,907)		(170)			(170)
Other	(6)		9	(8)	(1)
Ending balance (in shares) at Dec. 31, 2022		1,090					1
Ending balance at Dec. 31, 2022	30,408					1,931	$ 38	4,652	(2,759)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,976					188			188
Capital contributions from parent company						69		69
Other comprehensive income (loss)	(10)				$ (10)
Cash dividends on common stock	(3,035)			(3,035)		(185)			(185)
Other	(5)		$ (1)	$ 3
Ending balance (in shares) at Dec. 31, 2023		1,092					1
Ending balance at Dec. 31, 2023	$ 31,444					$ 2,003	$ 38	$ 4,721	$ (2,756)	$ 0

Consolidated Statements of In_2

Consolidated Statements of Income - SPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes (benefit)	496	795	267
Net Income	3,849	3,428	2,309
Net loss attributable to noncontrolling interests	(127)	(107)	(99)
Consolidated Net Income	3,976	3,524	2,393
Other revenues
Operating Revenues:
Total operating revenues	949	732	708
Operating Expenses:
Cost of sales	560	396	357
Fuel
Operating Expenses:
Cost of sales	4,365	6,835	4,010
Purchased power
Operating Expenses:
Cost of sales	883	1,593	978
Southern Power
Operating Revenues:
Total operating revenues	2,189	3,369	2,216
Operating Expenses:
Other operations and maintenance	473	482	423
Depreciation and amortization	504	516	517
Taxes other than income taxes	51	49	45
Loss on sales-type leases	0	1	40
Gain on dispositions, net	(20)	(2)	(41)
Total operating expenses	1,830	2,971	1,925
Operating Income	359	398	291
Other Income and (Expense):
Interest expense, net of amounts capitalized	(129)	(138)	(147)
Other income (expense), net	12	7	10
Total other income and (expense)	(117)	(131)	(137)
Earnings Before Income Taxes	242	267	154
Income taxes (benefit)	12	20	(13)
Net Income	230	247	167
Net loss attributable to noncontrolling interests	(127)	(107)	(99)
Consolidated Net Income	357	354	266
Southern Power \| Wholesale revenues, non-affiliates
Operating Revenues:
Total operating revenues	1,597	2,458	1,671
Southern Power \| Other revenues
Operating Revenues:
Total operating revenues	55	36	30
Southern Power \| Fuel
Operating Expenses:
Cost of sales	706	1,614	802
Southern Power \| Purchased power
Operating Expenses:
Cost of sales	$ 116	$ 311	$ 139

Consolidated Statements of Co_3

Consolidated Statements of Comprehensive Income - SPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Changes in fair value, net of tax	(41)	(60)	(49)
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(39)	48	98
Reclassification adjustment for amounts included in net income, net of tax	1	10	13
Total other comprehensive income (loss)	(10)	71	158
Comprehensive loss attributable to noncontrolling interests	(127)	(107)	(99)
Comprehensive Income	3,966	3,595	2,551
Southern Power
Net Income	230	247	167
Qualifying hedges:
Changes in fair value, net of tax	(3)	(91)	(67)
Reclassification adjustment for amounts included in net income, net of tax	11	81	89
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(7)	18	16
Reclassification adjustment for amounts included in net income, net of tax	0	2	2
Total other comprehensive income (loss)	1	10	40
Comprehensive loss attributable to noncontrolling interests	(127)	(107)	(99)
Comprehensive Income	$ 358	$ 364	$ 306

Consolidated Statements of Co_4

Consolidated Statements of Comprehensive Income - SPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualifying hedges, change in fair value, tax	$ (17)	$ (19)	$ (16)
Qualifying hedges, reclassification adjustment, tax	27	23	31
Pension and other postretirement benefit plans, gain (loss), tax	(14)	18	37
Reclassification adjustment for amounts included in net income, tax	0	3	5
Southern Power
Qualifying hedges, change in fair value, tax	(1)	(30)	(22)
Qualifying hedges, reclassification adjustment, tax	4	26	30
Pension and other postretirement benefit plans, gain (loss), tax	(2)	6	5
Reclassification adjustment for amounts included in net income, tax	$ 0	$ 1	$ 1

Consolidated Statements of Ca_3

Consolidated Statements of Cash Flows - SPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Net Income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Proceeds from dispositions	164	275	917
Payments pursuant to LTSAs	(99)	(190)	(188)
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase (decrease) in notes payable, net		(337)
Increase (decrease) in notes payable, net	973		530
Capital contributions from noncontrolling interests	21	73	501
Distributions to noncontrolling interests	(234)	(259)	(351)
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
LTSA credits utilized from the sale of spare parts	23	0	0
Contributions from noncontrolling interests	0	15	89
Contributions of wind turbine equipment	0	0	82
Southern Power
Operating Activities:
Net Income	230	247	167
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	524	543	542
Deferred income taxes	16	9	55
Utilization of federal investment tax credits	332	49	288
Amortization of investment tax credits	(58)	(58)	(58)
Gain on dispositions, net	(20)	(2)	(41)
Loss on sales-type leases	0	1	40
Other, net	28	18	(1)
Changes in certain current assets and liabilities —
-Receivables	121	(82)	(44)
-Prepaid income taxes	2	22	(16)
-Other current assets	(24)	(11)	(14)
-Accounts payable	(60)	68	30
-Other current liabilities	5	11	3
Net cash provided from operating activities	1,096	815	951
Investing Activities:
Acquisitions, net of cash acquired	(181)	0	(345)
Property additions	(118)	(100)	(396)
Change in construction payables	21	(69)	(15)
Proceeds from dispositions	59	48	24
Payments pursuant to LTSAs	(50)	(71)	(82)
Other investing activities	4	(2)	11
Net cash used for investing activities	(265)	(194)	(803)
Financing Activities:
Increase (decrease) in notes payable, net	(83)
Increase (decrease) in notes payable, net		10	36
Proceeds — Senior notes	0	0	400
Redemptions — Senior notes	(290)	(677)	(300)
Capital contributions from parent company	18	430	8
Return of capital to parent company	0	0	(271)
Capital contributions from noncontrolling interests	21	73	501
Distributions to noncontrolling interests	(234)	(259)	(351)
Payment of common stock dividends	(252)	(198)	(204)
Other financing activities	0	(2)	(14)
Net cash provided from financing activities	(820)	(623)	(195)
Net Change in Cash, Cash Equivalents, and Restricted Cash	11	(2)	(47)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	133	135	182
Cash, Cash Equivalents, and Restricted Cash at End of Year	144	133	135
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	122	142	140
Income taxes, net	(254)	(15)	(275)
Noncash transactions —
Accrued property additions at year-end	59	24	72
LTSA credits utilized from the sale of spare parts	23	0	0
Contributions from noncontrolling interests	0	15	89
Contributions of wind turbine equipment	$ 0	$ 0	$ 82

Consolidated Statements of Ca_4

Consolidated Statements of Cash Flows - SPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net cash paid for capitalized interest	$ 132	$ 103	$ 92
Southern Power
Net cash paid for capitalized interest	$ 3	$ 0	$ 6

Consolidated Balance Sheets -_3

Consolidated Balance Sheets - SPC - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts, net and affiliated	2,030	2,128
Other	519	637
Materials and supplies	1,989	1,664
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Equity investments in unconsolidated subsidiaries	1,368	1,443
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,432	1,531
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Notes payable	2,314	2,609
Accounts payable —
Accrued interest	652	614
Operating lease obligations	183	197
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Accumulated deferred ITCs	2,067	2,133
Operating lease obligations, deferred	1,307	1,388
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Common stock	5,423	5,417
Paid-in capital	13,775	13,673
Retained earnings	12,482	11,538
Accumulated other comprehensive loss	(177)	(167)
Total common stockholders' equity	31,444	30,408
Noncontrolling Interests	3,781	4,124
Total Stockholders' Equity (See accompanying statements)	35,225	34,532
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters
Southern Power
Current Assets:
Cash and cash equivalents	124	131
Receivables —
Customer accounts, net and affiliated	136	226
Other	54	70
Materials and supplies	80	88
Other current assets	92	55
Total current assets	523	621
Property, Plant, and Equipment:
In service	14,690	14,658
Less: Accumulated depreciation	4,119	3,661
Plant in service, net of depreciation	10,571	10,997
Construction work in progress	278	41
Total property, plant, and equipment	10,849	11,038
Other Property and Investments:
Intangible assets, net of amortization of $148 and $129, respectively	243	263
Equity investments in unconsolidated subsidiaries	0	49
Net investment in sales-type leases	148	154
Total other property and investments	391	466
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	488	489
Prepaid LTSAs	248	193
Income taxes receivable, non-current	17	19
Other deferred charges and assets	245	255
Total deferred charges and other assets	998	956
Total Assets	12,761	13,081
Current Liabilities:
Securities due within one year	0	290
Notes payable	138	225
Accounts payable —
Affiliated and other	91	67
Accrued taxes	26	24
Accrued interest	27	28
Operating lease obligations	29	28
Other current liabilities	97	83
Total current liabilities	490	884
Long-Term Debt	2,711	2,689
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	614	279
Accumulated deferred ITCs	1,498	1,556
Operating lease obligations, deferred	517	514
Other deferred credits and liabilities	233	243
Total deferred credits and other liabilities	2,862	2,592
Total Liabilities	6,063	6,165
Common Stockholders' Equity:
Common stock	0	0
Paid-in capital	1,088	1,069
Retained earnings	1,846	1,741
Accumulated other comprehensive loss	(17)	(18)
Total common stockholders' equity	2,917	2,792
Noncontrolling Interests	3,781	4,124
Total Stockholders' Equity (See accompanying statements)	6,698	6,916
Total Liabilities and Stockholders' Equity	12,761	13,081
Commitments and Contingent Matters
Southern Power \| Related Party
Receivables —
Customer accounts, net and affiliated	37	51
Accounts payable —
Affiliated and other	$ 82	$ 139

Consolidated Balance Sheets -_4

Consolidated Balance Sheets - SPC (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other intangible assets, amortization	$ 376	$ 340
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Southern Power
Other intangible assets, amortization	$ 148	$ 129
Cumulative preferred stock
Par value (in dollars per share)	$ 0.01	$ 0.01
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares outstanding (in shares)	1,000	1,000

Consolidated Statements of St_3

Consolidated Statements of Stockholders' Equity - SPC - USD ($) $ in Millions	Total	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Southern Power	Southern Power Total Common Stockholder's Equity	Southern Power Paid-In Capital	Southern Power Retained Earnings	Southern Power Accumulated Other Comprehensive Income (Loss)	Southern Power Noncontrolling Interests
Beginning balance at Dec. 31, 2020	$ 32,234	$ 11,834	$ 11,311	$ (395)	$ 4,262	$ 6,631	$ 2,369	$ 914	$ 1,522	$ (67)	$ 4,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,309					167	266		266		(99)
Return of capital to parent company						(271)	(271)	(271)
Capital contributions from parent company						10	10	10
Other comprehensive income (loss)	158			158		40	40			40
Cash dividends on common stock	(2,777)		(2,777)			(204)	(204)		(204)
Capital contributions from noncontrolling interests	590				590	590					590
Distributions to noncontrolling interests	(351)				(351)	(351)					(351)
Other	(7)	(8)	2			(14)	(14)	(15)	1
Ending balance at Dec. 31, 2021	32,276	11,950	10,929	(237)	4,402	6,598	2,196	638	1,585	(27)	4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	3,428					247	354		354		(107)
Capital contributions from parent company						431	431	431
Other comprehensive income (loss)	71			71		10	10			10
Cash dividends on common stock	(2,907)		(2,907)			(198)	(198)		(198)
Capital contributions from noncontrolling interests	88				88	88					88
Distributions to noncontrolling interests	(259)				(259)	(259)					(259)
Other	(6)	9	(8)	(1)		(1)	(1)			(1)	0
Ending balance at Dec. 31, 2022	34,532	13,673	11,538	(167)	4,124	6,916	2,792	1,069	1,741	(18)	4,124
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	3,849					230	357		357		(127)
Capital contributions from parent company						19	19	19
Other comprehensive income (loss)	(10)			(10)		1	1			1
Cash dividends on common stock	(3,035)		(3,035)			(252)	(252)		(252)
Capital contributions from noncontrolling interests	21				21	21					21
Distributions to noncontrolling interests	(236)				(236)	(236)					(236)
Other	(5)	(1)	3		(1)	(1)	0			0	(1)
Ending balance at Dec. 31, 2023	$ 35,225	$ 13,775	$ 12,482	$ (177)	$ 3,781	$ 6,698	$ 2,917	$ 1,088	$ 1,846	$ (17)	$ 3,781

Consolidated Statements of In_3

Consolidated Statements of Income - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Revenues:
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Operating Expenses:
Other operations and maintenance	6,093	6,573	5,902
Depreciation and amortization	4,525	3,663	3,565
Taxes other than income taxes	1,425	1,411	1,290
Impairment charges	0	251	2
Total operating expenses	19,427	23,909	19,415
Operating Income	5,826	5,370	3,698
Other Income and (Expense):
Earnings from equity method investments	144	151	76
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Total other income and (expense)	(1,481)	(1,147)	(1,122)
Earnings Before Income Taxes	4,345	4,223	2,576
Income taxes	496	795	267
Net Income	3,849	3,428	2,309
Southern Company Gas
Operating Revenues:
Total operating revenues	4,702	5,962	4,380
Operating Expenses:
Cost of natural gas	1,644	3,004	1,619
Other operations and maintenance	1,194	1,176	1,072
Depreciation and amortization	582	559	536
Taxes other than income taxes	262	282	225
Impairment charges	0	131	0
Estimated loss on regulatory disallowance	88	0	0
Gain on dispositions, net	(7)	(4)	(127)
Total operating expenses	3,763	5,148	3,325
Operating Income	939	814	1,055
Other Income and (Expense):
Earnings from equity method investments	140	148	50
Interest expense, net of amounts capitalized	(310)	(263)	(238)
Other income (expense), net	57	53	(53)
Total other income and (expense)	(113)	(62)	(241)
Earnings Before Income Taxes	826	752	814
Income taxes	211	180	275
Net Income	$ 615	$ 572	$ 539

Consolidated Statements of In_4

Consolidated Statements of Income - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Southern Company Gas
Excise taxes collected	$ 133	$ 162	$ 122

Consolidated Statements of Co_5

Consolidated Statements of Comprehensive Income - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net Income	$ 3,849	$ 3,428	$ 2,309
Qualifying hedges:
Changes in fair value, net of tax	(41)	(60)	(49)
Reclassification adjustment for amounts included in net income, net of tax	69	73	96
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(39)	48	98
Reclassification adjustment for amounts included in net income, net of tax	1	10	13
Total other comprehensive income (loss)	(10)	71	158
Comprehensive Income	3,966	3,595	2,551
Southern Company Gas
Net Income	615	572	539
Qualifying hedges:
Changes in fair value, net of tax	(45)	13	17
Reclassification adjustment for amounts included in net income, net of tax	46	(24)	(11)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	(15)	18	40
Reclassification adjustment for amounts included in net income, net of tax	(1)	0	0
Total other comprehensive income (loss)	(15)	7	46
Comprehensive Income	$ 600	$ 579	$ 585

Consolidated Statements of Co_6

Consolidated Statements of Comprehensive Income - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Qualifying hedges, change in fair value, tax	$ (17)	$ (19)	$ (16)
Qualifying hedges, reclassification adjustment, tax	27	23	31
Pension and other postretirement benefit plans, gain (loss), tax	(14)	18	37
Reclassification adjustment for amounts included in net income, tax	0	3	5
Southern Company Gas
Qualifying hedges, change in fair value, tax	(18)	5	5
Qualifying hedges, reclassification adjustment, tax	19	(9)	(5)
Pension and other postretirement benefit plans, gain (loss), tax	(7)	8	17
Reclassification adjustment for amounts included in net income, tax	$ 0	$ 0	$ 0

Consolidated Statements of Ca_5

Consolidated Statements of Cash Flows - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating Activities:
Consolidated net income	$ 3,849	$ 3,428	$ 2,309
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,986	4,064	3,973
Deferred income taxes	63	670	(49)
Natural gas cost under recovery – long-term	0	207	(207)
Other, net	(138)	(25)	(89)
Changes in certain current assets and liabilities —
-Receivables	482	(771)	(77)
-Natural gas cost under recovery	108	158	(266)
-Other current assets	(106)	(186)	(270)
-Accounts payable	(863)	1,021	(8)
-Other current liabilities	214	204	(258)
Net cash provided from operating activities	7,553	6,302	6,169
Investing Activities:
Property additions	(9,095)	(7,923)	(7,586)
Cost of removal, net of salvage	(592)	(649)	(442)
Change in construction payables, net	18	203	(124)
Proceeds from dispositions	164	275	917
Other investing activities	(43)	(133)	75
Net cash used for investing activities	(9,668)	(8,430)	(7,353)
Financing Activities:
Increase (decrease) in notes payable, net		(337)
Increase (decrease) in notes payable, net	973		530
Proceeds —
Short-term borrowings	350	2,650	325
Redemptions and repurchases —
Short-term borrowings	(1,630)	(1,150)	(25)
Payment of common stock dividends	(3,035)	(2,907)	(2,777)
Other financing activities	(160)	(218)	(266)
Net cash provided from financing activities	999	2,336	1,945
Net Change in Cash, Cash Equivalents, and Restricted Cash	(1,116)	208	761
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	2,037	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Year	921	2,037	1,829
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	2,184	1,758	1,718
Income taxes, net	132	146	93
Noncash transactions —
Accrued property additions at year-end	1,027	1,024	866
Southern Company Gas
Operating Activities:
Consolidated net income	615	572	539
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	582	558	536
Deferred income taxes	126	17	259
Impairment charges	0	131	84
Gain on dispositions, net	(7)	(4)	(127)
Mark-to-market adjustments	(7)	12	194
Natural gas cost under recovery – long-term	0	207	(207)
Estimated loss on regulatory disallowance	(96)	0	0
Other, net	(60)	(32)	(30)
Changes in certain current assets and liabilities —
-Receivables	431	(345)	(143)
-Natural gas for sale, net of temporary LIFO liquidation	19	(77)	8
-Prepaid income taxes	(11)	19	(82)
-Natural gas cost under recovery	108	158	(266)
-Other current assets	(17)	(6)	(116)
-Accounts payable	(276)	299	40
-Natural gas cost over recovery	214	0	0
-Other current liabilities	(51)	10	(26)
Net cash provided from operating activities	1,762	1,519	663
Investing Activities:
Property additions	(1,561)	(1,533)	(1,421)
Cost of removal, net of salvage	(104)	(112)	(106)
Change in construction payables, net	(38)	65	(29)
Investments in unconsolidated subsidiaries	(11)	(165)	(5)
Proceeds from dispositions	42	150	150
Other investing activities	16	15	32
Net cash used for investing activities	(1,656)	(1,580)	(1,379)
Financing Activities:
Increase (decrease) in notes payable, net	(153)	(341)
Increase (decrease) in notes payable, net			585
Proceeds —
Senior notes	500	500	450
First mortgage bonds	275	175	200
Short-term borrowings	0	50	300
Other long-term debt	37	22	0
Redemptions and repurchases —
Senior notes	0	0	(300)
Short-term borrowings	(200)	(150)	0
Medium-term notes	(350)	(46)	(30)
First mortgage bonds	(50)	0	0
Capital contributions from parent company	373	406	72
Payment of common stock dividends	(585)	(519)	(530)
Other financing activities	(1)	(1)	(2)
Net cash provided from financing activities	(154)	96	745
Net Change in Cash, Cash Equivalents, and Restricted Cash	(48)	35	29
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	83	48	19
Cash, Cash Equivalents, and Restricted Cash at End of Year	35	83	48
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	291	258	244
Income taxes, net	91	208	57
Noncash transactions —
Accrued property additions at year-end	$ 139	$ 177	$ 113

Consolidated Statements of Ca_6

Consolidated Statements of Cash Flows - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net cash paid for capitalized interest	$ 132	$ 103	$ 92
Southern Company Gas
Net cash paid for capitalized interest	$ 16	$ 10	$ 8

Consolidated Balance Sheets - G

Consolidated Balance Sheets - GAS - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 748	$ 1,917
Receivables —
Customer accounts	2,030	2,128
Unbilled revenues	786	1,012
Other accounts and notes	519	637
Accumulated provision for uncollectible accounts	(68)	(71)
Natural gas for sale	420	438
Prepaid expenses	406	347
Natural gas cost under recovery	0	108
Other regulatory assets	1,120	860
Other current assets	533	344
Total current assets	10,432	10,416
Property, Plant, and Equipment:
In service	128,428	117,529
Less: Accumulated depreciation	37,725	35,297
Plant in service, net of depreciation	90,703	82,232
Construction work in progress	7,784	10,896
Total property, plant, and equipment	99,844	94,570
Other Property and Investments:
Goodwill	5,161	5,161
Equity investments in unconsolidated subsidiaries	1,368	1,443
Other intangible assets, net of amortization	368	406
Miscellaneous property and investments	665	602
Total other property and investments	9,986	9,757
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,432	1,531
Prepaid pension costs	2,079	2,290
Other regulatory assets, deferred	6,264	5,918
Other deferred charges and assets	1,468	1,485
Total deferred charges and other assets	19,069	20,148
Total Assets	139,331	134,891
Current Liabilities:
Securities due within one year	2,476	4,285
Notes payable	2,314	2,609
Accounts payable —
Customer deposits	503	502
Accrued compensation	1,151	1,127
Natural gas cost over recovery	214	0
Other regulatory liabilities	141	382
Other current liabilities	1,029	787
Total current liabilities	13,467	15,724
Long-Term Debt	57,210	50,656
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,990	10,036
Deferred credits related to income taxes	4,674	5,235
Employee benefit obligations	1,115	1,238
Operating lease obligations	1,307	1,388
Other cost of removal obligations	1,957	1,903
Other deferred credits and liabilities	1,031	1,167
Total deferred credits and other liabilities	33,429	33,979
Total Liabilities	104,106	100,359
Common Stockholders' Equity:
Paid-in capital	13,775	13,673
Accumulated deficit	12,482	11,538
Accumulated other comprehensive income (loss)	(177)	(167)
Total common stockholders' equity	31,444	30,408
Total Liabilities and Stockholders' Equity	139,331	134,891
Commitments and Contingent Matters
Operating lease obligations - current	183	197
Southern Company Gas
Current Assets:
Cash and cash equivalents	33	81
Receivables —
Customer accounts	405	616
Unbilled revenues	261	453
Other accounts and notes	47	76
Accumulated provision for uncollectible accounts	(44)	(50)
Natural gas for sale	420	438
Prepaid expenses	107	93
Natural gas cost under recovery	0	108
Other regulatory assets	141	119
Other current assets	116	104
Total current assets	1,486	2,038
Property, Plant, and Equipment:
In service	20,840	19,723
Less: Accumulated depreciation	5,534	5,276
Plant in service, net of depreciation	15,306	14,447
Construction work in progress	1,110	909
Total property, plant, and equipment	16,416	15,356
Other Property and Investments:
Goodwill	5,015	5,015
Equity investments in unconsolidated subsidiaries	1,235	1,276
Other intangible assets, net of amortization	16	26
Miscellaneous property and investments	25	28
Total other property and investments	6,291	6,345
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	47	57
Prepaid pension costs	158	183
Other regulatory assets, deferred	504	497
Other deferred charges and assets	181	145
Total deferred charges and other assets	890	882
Total Assets	25,083	24,621
Current Liabilities:
Securities due within one year	0	400
Notes payable	415	768
Accounts payable —
Affiliated and other	424	701
Customer deposits	126	125
Accrued taxes	77	77
Accrued compensation	112	105
Natural gas cost over recovery	214	0
Other regulatory liabilities	19	36
Other current liabilities	232	254
Total current liabilities	1,708	2,570
Long-Term Debt	7,833	7,042
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	1,671	1,560
Deferred credits related to income taxes	759	788
Employee benefit obligations	110	120
Operating lease obligations	40	51
Other cost of removal obligations	1,771	1,707
Accrued environmental remediation	192	207
Other deferred credits and liabilities	196	179
Total deferred credits and other liabilities	4,739	4,612
Total Liabilities	14,280	14,224
Common Stockholders' Equity:
Paid-in capital	10,836	10,445
Accumulated deficit	(49)	(79)
Accumulated other comprehensive income (loss)	16	31
Total common stockholders' equity	10,803	10,397
Total Liabilities and Stockholders' Equity	25,083	24,621
Commitments and Contingent Matters
Operating lease obligations - current	11	9
Southern Company Gas \| Related Party
Accounts payable —
Affiliated and other	$ 89	$ 104

Consolidated Balance Sheets -_5

Consolidated Balance Sheets - GAS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other intangible assets, amortization	$ 376	$ 340
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Southern Company Gas
Other intangible assets, amortization	$ 166	$ 156
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares outstanding (in shares)	100	100

Consolidated Statements of Comm

Consolidated Statements of Common Stockholders' Equity - GAS - USD ($) $ in Millions	Total	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Southern Company Gas	Southern Company Gas Paid-In Capital	Southern Company Gas Retained Earnings	Southern Company Gas Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2020				$ 9,767	$ 9,930	$ (141)	$ (22)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	$ 2,309			539		539
Capital contributions from parent company				94	94
Other comprehensive income (loss)	158		$ 158	46			46
Cash dividends on common stock	(2,777)	$ (2,777)		(530)		(530)
Ending balance at Dec. 31, 2021				9,916	10,024	(132)	24
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,428			572		572
Capital contributions from parent company				421	421
Other comprehensive income (loss)	71		71	7			7
Cash dividends on common stock	(2,907)	(2,907)		(519)		(519)
Ending balance at Dec. 31, 2022	30,408			10,397	10,445	(79)	31
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	3,849			615		615
Capital contributions from parent company				391	391
Other comprehensive income (loss)	(10)		$ (10)	(15)			(15)
Cash dividends on common stock	(3,035)	$ (3,035)		(585)		(585)
Ending balance at Dec. 31, 2023	$ 31,444			$ 10,803	$ 10,836	$ (49)	$ 16

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	Dec. 31, 2023
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES General Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. Prior to the sale of Sequent on July 1, 2021, these businesses also included wholesale gas services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plant Hatch and Plant Vogtle Units 1 through 3, and is currently managing construction and start-up of Plant Vogtle Unit 4. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers. See Note 15 for information regarding the sale of Sequent. The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in a HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information. The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies. The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows. Recently Adopted Accounting Standards In 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04) providing temporary guidance to ease the potential burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which began phasing out on December 31, 2021. The discontinuation date of the overnight 1-, 3-, 6-, and 12-month tenors of LIBOR was June 30, 2023, which was beyond the original effective date of ASU 2020-04; therefore, in December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 (ASU 2022-06) to defer the sunset date of ASU 2020-04 from December 31, 2022 to December 31, 2024. The amendments were elective and applied to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The guidance (i) simplified accounting analyses under current GAAP for contract modifications; (ii) simplified the assessment of hedge effectiveness and allows hedging relationships affected by reference rate reform to continue; and (iii) allowed a one-time election to sell or transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform. An entity could elect to apply the amendments prospectively from March 12, 2020 through December 31, 2024 by accounting topic. The Registrants elected to apply the amendments to modifications of debt and derivative arrangements that meet the scope of ASU 2020-04 and ASU 2022-06. Certain provisions in PPAs at Southern Power included references to LIBOR. Contract amendments have been executed to change to a SOFR-based interest rate. Southern Power adopted and applied the practical expedients guidance to these PPAs. Additionally, the Registrants referenced LIBOR for certain debt and hedging arrangements. As of July 1, 2023, all of the debt and hedging arrangements of the Registrants had transitioned to a SOFR-based interest rate based on the terms of the agreements. There were no material impacts from the transition to SOFR and no impacts to any existing accounting conclusions. See Note 14 under "Interest Rate Derivatives" for additional information. Affiliate Transactions The traditional electric operating companies, Southern Power, and Southern Company Gas have agreements with SCS under which certain of the following services are rendered to them at direct or allocated cost: general executive and advisory, general and design engineering, operations, purchasing, accounting, finance, treasury, legal, tax, information technology, marketing, auditing, insurance and pension administration, human resources, systems and procedures, digital wireless communications, cellular tower space, and other services with respect to business and operations, construction management, and Southern Company power pool transactions. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services from SCS in 2023, 2022, and 2021 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2023 $ 611 $ 857 $ 113 $ 86 $ 261 2022 549 762 115 86 262 2021 504 663 120 89 239 Alabama Power and Georgia Power also have agreements with Southern Nuclear under which Southern Nuclear renders the following nuclear-related services at cost: general executive and advisory services; general operations, management, and technical services; administrative services including procurement, accounting, employee relations, systems, and procedures services; strategic planning and budgeting services; other services with respect to business and operations; and, for Georgia Power, construction management. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services in 2023, 2022, and 2021 amounted to $251 million, $267 million, and $258 million, respectively, for Alabama Power and $899 million, $895 million, and $906 million, respectively, for Georgia Power. See Note 2 under "Georgia Power – Nuclear Construction" for additional information regarding Southern Nuclear's construction management of Plant Vogtle Unit 4 for Georgia Power. Cost allocation methodologies used by SCS and Southern Nuclear prior to the repeal of the Public Utility Holding Company Act of 1935, as amended, were approved by the SEC. Subsequently, additional cost allocation methodologies have been reported to the FERC and management believes they are reasonable. The FERC permits services to be rendered at cost by system service companies. Alabama Power's and Georgia Power's power purchases from affiliates through the Southern Company power pool are included in purchased power, affiliates on their respective statements of income. Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows: Mississippi Southern (in millions) 2023 $ 4 $ 13 2022 4 29 2021 9 15 Georgia Power has entered into several PPAs with Southern Power for capacity and energy. Georgia Power's total expenses associated with these PPAs were $143 million, $151 million, and $132 million in 2023, 2022, and 2021, respectively. Southern Power's total revenues from all PPAs with Georgia Power, included in wholesale revenue affiliates on Southern Power's consolidated statements of income, were $145 million, $154 million, and $139 million for 2023, 2022, and 2021, respectively. Included within these revenues were affiliate PPAs accounted for as operating leases, which totaled $116 million, $116 million, and $112 million for 2023, 2022, and 2021, respectively. See Note 9 for additional information. Also see Note 2 under "Georgia Power – Integrated Resource Plans" for information regarding additional affiliate PPAs commencing in 2024. SCS (as agent for Alabama Power, Georgia Power, and Southern Power) and Southern Company Gas have long-term interstate natural gas transportation agreements with SNG that are governed by the terms and conditions of SNG's natural gas tariff and are subject to FERC regulation. See Note 7 under "Southern Company Gas – Equity Method Investments" for additional information. Transportation costs under these agreements in 2023, 2022, and 2021 were as follows: Alabama Georgia Southern Southern Company Gas (in millions) 2023 $ 12 $ 101 $ 34 $ 28 2022 18 99 37 27 2021 14 108 31 29 SCS, as agent for the traditional electric operating companies and Southern Power, has agreements with certain subsidiaries of Southern Company Gas to purchase natural gas. Natural gas purchases made under these agreements were immaterial for Alabama Power, Georgia Power, and Mississippi Power for all periods presented, immaterial for Southern Power in 2023 and 2022, and $18 million for Southern Power in 2021. Alabama Power and Mississippi Power jointly own Plant Greene County. The companies have an agreement under which Alabama Power operates Plant Greene County and Mississippi Power reimburses Alabama Power for its proportionate share of non-fuel operations and maintenance expenses, which totaled $5 million, $6 million, and $10 million in 2023, 2022, and 2021, respectively. See Note 5 under "Joint Ownership Agreements" for additional information. Alabama Power, Georgia Power, and Mississippi Power each have agreements with PowerSecure for equipment purchases and/or services related to utility infrastructure construction, distributed energy, and energy efficiency projects. Costs under these agreements were immaterial for all periods presented. Southern Company Gas has a $77 million contract with the U.S. General Services Administration to increase energy efficiency at certain federal buildings across Georgia, with completion expected by the end of 2024. Southern Company Gas engaged PowerSecure to provide the majority of the construction services under the contract. During 2023 and 2022, Southern Company Gas paid $29 million and $10 million, respectively, to PowerSecure related to this agreement. See Note 7 under "SEGCO" for information regarding Alabama Power's and Georgia Power's equity method investment in SEGCO and related affiliate purchased power costs, as well as Alabama Power's gas pipeline ownership agreement with SEGCO. Southern Power has several agreements with SCS for transmission services, which are billed to Southern Power based on the Southern Company Open Access Transmission Tariff as filed with the FERC. Transmission services purchased by Southern Power from SCS totaled $33 million, $39 million, and $28 million for 2023, 2022, and 2021, respectively, and were charged to other operations and maintenance expenses in Southern Power's consolidated statements of income. The traditional electric operating companies and Southern Power may jointly enter into various types of wholesale energy, natural gas, and certain other contracts, either directly or through SCS as agent. Each participating company may be jointly and severally liable for the obligations incurred under these agreements. See Note 14 under "Contingent Features" for additional information. Southern Power and the traditional electric operating companies generally settle amounts related to the above transactions on a monthly basis in the month following the performance of such services or the purchase or sale of electricity. See "Revenues – Southern Power" herein for additional information. The traditional electric operating companies, Southern Power, and Southern Company Gas provide incidental services to and receive such services from other Southern Company subsidiaries which are generally minor in duration and amount. Except as described herein, the traditional electric operating companies, Southern Power, and Southern Company Gas neither provided nor received any material services to or from affiliates in any year presented. Regulatory Assets and Liabilities The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process. In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the traditional electric operating company or the natural gas distribution utility would be required to determine if any impairment to other assets, including plant, exists and write down the assets, if impaired, to their fair values. All regulatory assets and liabilities are to be reflected in rates. See Note 2 for additional information including details of regulatory assets and liabilities reflected in the balance sheets for Southern Company, the traditional electric operating companies, and Southern Company Gas. Revenues The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information. Traditional Electric Operating Companies The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are accrued at the end of each fiscal period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies. Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer. For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation. Southern Power Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, normal sale derivatives, or contracts with customers. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease. Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer. Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation. When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements. Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information. Southern Company Gas Gas Distribution Operations Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities. Atlanta Gas Light operates in a deregulated natural gas market wher eby M arketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Company Gas recognizes revenue as the performance obligations are satisfied over time as natural gas is delivered to the customer. The performance obligations related to wholesale gas services are satisfied, and revenue is recognized, at a point in time when natural gas is delivered to the customer. Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage. Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period. The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $20 million, $(5) million, and $11 million in 2023, 2022, and 2021, respectively. These programs are as follows: • Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas; • Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and • Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year. Wholesale Gas Services Prior to the sale of Sequent on July 1, 2021, Southern Company Gas netted revenues from energy and risk management activities with the associated costs. Profits from sales between segments were eliminated and recognized as goods or services sold to end-use customers. Southern Company Gas recorded wholesale gas services' transactions that qualified as derivatives at fair value with changes in fair value recognized in earnings in the period of change and characterized as unrealized gains or losses. Gains and losses on derivatives held for energy trading purposes were presented on a net basis in revenue. See Note 15 under "Southern Company Gas" for additional information on the sale of Sequent. Gas Marketing Services Southern Company Gas recognizes revenues from natural gas sales and transportation services in the same period in which the related volumes are delivered to customers and recognizes sales revenues from residential and certain commercial and industrial customers on the basis of scheduled meter readings. Southern Company Gas also recognizes unbilled revenues for estimated deliveries of gas not yet billed to these customers from the most recent meter reading date to the end of the accounting period. For other commercial and industrial customers and for all wholesale customers, revenues are based on actual deliveries during the period. Southern Company Gas recognizes revenues on 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts. Concentration of Revenue Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer comprises 10% or more of each company's revenues. Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs, which are subject to regulation by the FERC. The contracts with these wholesale customers represented 14.0% of Mississippi Power's total operating revenues in 2023. Fuel Costs Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs. Cost of Natural Gas Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively. Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas and gains and losses associated with certain derivatives. Income Taxes The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production. Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2023 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Current and Deferred Income Taxes – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information. In June 2023, the IRS issued temporary regulations related to the transferability of certain tax credits under the IRA. Southern Company and certain subsidiaries have tax credits that are eligible to be transferred. The discount recorded on transferred credits is booked through income tax expense. Under current tax law, Georgia Power is eligible to generate advanced nuclear PTCs for Plant Vogtle Unit 3, which are recognized as an income tax benefit based on KWH production and are eligible to be transferred. Pursuant to the Global Amendments to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Joint Owner Contracts"), Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Unit 3 from the other Vogtle Owners. The gain recognized on the purchase of the joint owner PTCs is recognized as an income tax benefit. The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information. Other Taxes Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer. Southern Company Gas is taxed on its ga

REGULATORY MATTERS

REGULATORY MATTERS	12 Months Ended
REGULATORY MATTERS	Dec. 31, 2023
Regulated Operations [Abstract]
REGULATORY MATTERS	REGULATORY MATTERS Regulatory Assets and Liabilities Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2023 and 2022 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2023 AROs (a)(w) $ 5,733 $ 1,936 $ 3,505 $ 247 $ — Retiree benefit plans (b)(w) 3,011 815 976 140 146 Remaining net book value of retired assets (c) 1,357 499 841 17 — Deferred income tax charges (d) 897 262 605 28 — Under recovered regulatory clause revenues (e) 413 381 — 12 20 Fuel-hedging (realized and unrealized) losses (f) 270 100 121 49 — Deferred depreciation (g) 270 143 127 — — Environmental remediation (h)(w) 255 — 20 — 235 Loss on reacquired debt (i) 238 35 197 5 1 Vacation pay (j)(w) 217 83 107 11 16 Software and cloud computing costs (k) 150 59 84 2 5 Regulatory clauses (l) 140 112 — — 28 Storm damage (m) 92 — 54 38 — Nuclear outage (n) 83 50 33 — — Long-term debt fair value adjustment (o) 60 — — — 60 Qualifying repairs of natural gas distribution systems (p) 40 — — — 40 Plant Daniel Units 3 and 4 (q) 25 — — 25 — Kemper County energy facility assets, net (r) 7 — — 7 — Other regulatory assets (s) 182 39 33 18 93 Deferred income tax credits (d) (4,686) (1,506) (2,161) (241) (759) Other cost of removal obligations (a) (1,312) 28 617 (186) (1,771) Over recovered regulatory clause revenues (e) (287) (3) (46) — (238) Reliability reserves (t) (179) (143) — (36) — Storm/property damage reserves (t) (120) (76) — (44) — Customer refunds (u) (19) (15) (4) — — Fuel-hedging (realized and unrealized) gains (f) (6) (5) (1) — Other regulatory liabilities (v) (308) (74) (18) (2) (101) Total regulatory assets (liabilities), net $ 6,523 $ 2,720 $ 5,090 $ 90 $ (2,225) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(w) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(w) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (e) 953 788 — 31 134 Deferred income tax charges (d) 866 250 583 30 — Environmental remediation (h)(w) 294 — 25 — 269 Loss on reacquired debt (i) 257 38 213 5 1 Vacation pay (j)(w) 212 82 108 10 12 Regulatory clauses (l) 142 142 — — — Software and cloud computing costs (k) 111 46 59 — 6 Nuclear outage (n) 82 52 30 — — Long-term debt fair value adjustment (o) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (f) 60 15 45 — — Storm damage (m) 44 — — 44 — Plant Daniel Units 3 and 4 (q) 27 — — 27 — Qualifying repairs of natural gas distribution systems (p) 26 — — — 26 Kemper County energy facility assets, net (r) 20 — — 20 — Other regulatory assets (s) 171 36 27 16 92 Deferred income tax credits (d) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (t) (216) (97) (83) (36) — Reliability reserves (t) (191) (166) — (25) — Customer refunds (u) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (f) (83) (38) (21) (24) — Over recovered regulatory clause revenues (e) (64) — (38) — (26) Other regulatory liabilities (v) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power and Mississippi Power and up to 14 years for Georgia Power and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Unit 10 ($451 million at December 31, 2023) being amortized over 14 years (through 2037) and Plant Barry Unit 4 ($39 million at December 31, 2023) being amortized over 11 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2, Plant Hammond Units 1 through 4, and Plant Branch Unit 4 (totaling $488 million, $339 million, and $8 million, respectively, at December 31, 2023) are being amortized over remaining periods between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Deferred income tax charges are recovered and deferred income tax credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2023 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2024 and/or 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts include $145 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 to be recovered over a 10-year period beginning the month after Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. Mississippi Power : Related amounts include retail deferred income tax liabilities ($11 million at December 31, 2023) that are expected to be fully amortized through 2024. Southern Company Gas : Related amounts include deferred income tax liabilities ($1 million at December 31, 2023) being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (e) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to seven years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2023, $12 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (f) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (g) Alabama Power : Represents deferred depreciation expense for Plant Barry Unit 5 ($57 million at December 31, 2023) and Plant Barry common coal assets ($24 million at December 31, 2023) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($62 million at December 31, 2023) to be amortized until 2039 beginning when the assets are retired. Georgia Power : Represents deferred depreciation expense for Plant Scherer Units 1 through 3 ($70 million at December 31, 2023) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($40 million at December 31, 2023) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($17 million at December 31, 2023) to be amortized over a 10-year period beginning the month after Plant Vogtle Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. (h) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (i) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2023, the remaining amortization periods do not exceed 24 years for Alabama Power, 29 years for Georgia Power, 18 years for Mississippi Power, and four years for Southern Company Gas. (j) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (k) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027) and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). (l) Alabama Power : Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. Southern Company Gas : Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years. (m) See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over a seven-year period through 2029. (n) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (o) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 15 years at December 31, 2023. (p) Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years. (q) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2023, consists of the $17 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized through 2035. (r) At December 31, 2023, includes $9 million of regulatory assets (wholesale) expected to be fully amortized by 2035 and $2 million of regulatory liabilities (retail) expected to be fully amortized by 2024. (s) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 20 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 15 years for Southern Company Gas. (t) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (u) Primarily includes approximately $15 million and $62 million at December 31, 2023 and 2022, respectively, for Alabama Power and $119 million at December 31, 2022 for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (v) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 11 years for Alabama Power, nine years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas. (w) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability. Alabama Power Alabama Power's revenues from regulated retail operations are collected through various rate mechanisms subject to the oversight of the Alabama PSC. Alabama Power currently recovers its costs from the regulated retail business primarily through Rate RSE, Rate CNP, Rate ECR, and Rate NDR. In addition, the Alabama PSC issues accounting orders to address current events impacting Alabama Power. Renewable Generation Certificate Through the issuance of a Renewable Generation Certificate (RGC), Alabama Power is authorized by the Alabama PSC to procure renewable capacity and energy and to market the related energy and environmental attributes to customers and other third parties. On April 4, 2023, the Alabama PSC approved two new solar PPAs totaling 160 MWs. Upon approval of these PPAs, Alabama Power had procured solar capacity totaling approximately 490 MWs under the RGC's original 500-MW limit. On June 14, 2023, the Alabama PSC issued an order approving modifications to Alabama Power's RGC. The modifications authorized Alabama Power to procure an additional 2,400 MWs of renewable capacity and energy by June 14, 2029 and to market the related energy and environmental attributes to customers and other third parties. The modifications also increased the size of allowable renewable projects from 80 MWs to 200 MWs and increased the annual approval limit from 160 MWs to 400 MWs. Rate RSE The Alabama PSC has adopted Rate RSE that provides for periodic annual adjustments based upon Alabama Power's projected weighted common equity return (WCER) compared to an allowable range. Rate RSE adjustments are based on forward-looking information for the applicable upcoming calendar year. Rate RSE adjustments for any two-year period, when averaged together, cannot exceed 4.0% and any annual adjustment is limited to 5.0%. When the projected WCER is under the allowed range, there is an adjusting point of 5.98% and eligibility for a performance-based adder of seven basis points, or 0.07%, to the WCER adjusting point if Alabama Power (i) has an "A" credit rating equivalent with at least one of the recognized rating agencies or (ii) is in the top one-third of a designated customer value benchmark survey. Alabama Power continues to reduce growth in total debt by increasing equity, with corresponding reductions in debt issuances, thereby de-leveraging its capital structure. Alabama Power's goal is to achieve an equity ratio of approximately 55% by the end of 2025. At December 31, 2023 and 2022, Alabama Power's equity ratio was approximately 52.3% and 52.2%, respectively. Generally, during a year without a Rate RSE upward adjustment, if Alabama Power's actual WCER is between 6.15% and 7.65%, customers will receive 25% of the amount between 6.15% and 6.65%, 40% of the amount between 6.65% and 7.15%, and 75% of the amount between 7.15% and 7.65%. Customers will receive all amounts in excess of an actual WCER of 7.65%. During a year with a Rate RSE upward adjustment, if Alabama Power's actual WCER exceeds 6.15%, customers receive 50% of the amount between 6.15% and 6.90% and all amounts in excess of an actual WCER of 6.90%. Alabama Power's ability to retain a portion of the revenue that causes the actual WCER for a given year to exceed the allowed range positions Alabama Power to address the pressure on its credit quality, without increasing retail rates under Rate RSE in the near term. There is no provision for additional customer billings should the actual retail return fall below the WCER range. Retail rates under Rate RSE did not change for 2022 or 2023. For the years ended December 31, 2021, 2022, and 2023, Alabama Power's WCER exceeded 6.15%, resulting in Alabama Power establishing a current regulatory liability of $181 million, $62 million, and $15 million, respectively, for Rate RSE refunds. In accordance with an Alabama PSC order issued in February 2022, Alabama Power applied $126 million of the 2021 refund to reduce the Rate ECR under recovered balance and the remaining $55 million was refunded to customers through bill credits in July 2022. In accordance with an Alabama PSC order issued on February 7, 2023, Alabama Power refunded the 2022 amount to customers through bill credits in August 2023. The $15 million regulatory liability at December 31, 2023 will be refunded to customers through bill credits in April 2024. On December 1, 2023, Alabama Power made its required annual Rate RSE submission to the Alabama PSC of projected data for calendar year 2024. Projected earnings were within the specified range; therefore, retail rates under Rate RSE remain unchanged for 2024. Excess Accumulated Deferred Income Tax Accounting Order In December 2022, the Alabama PSC directed Alabama Power to accelerate the amortization of a regulatory liability associated with excess federal accumulated deferred income taxes. Under this order, in 2023, approximately $304 million was returned to customers through bill credits to offset the impact of the rate increase discussed under "Rate CNP Depreciation" herein. On October 3, 2023, the Alabama PSC issued an order modifying its December 2022 order and authorizing Alabama Power to (i) flow back in 2023 approximately $24 million of certain federal excess accumulated deferred income taxes resulting from the Tax Cuts and Jobs Act of 2017 and (ii) make available any remaining balance of excess accumulated deferred income taxes at the end of 2023 for the benefit of customers in 2024 and/or 2025. At December 31, 2023, the remaining balance was $81 million, of which approximately $67 million and $14 million will flow back in 2024 and 2025, respectively, for the benefit of customers. Rate CNP New Plant Rate CNP New Plant allows for recovery of Alabama Power's retail costs associated with newly developed or acquired certificated generating facilities placed into retail service. No adjustments to Rate CNP New Plant occurred during the period January 2021 through October 2022. In July 2022, the Alabama PSC approved a CCN authorizing Alabama Power to complete the acquisition of the Calhoun Generating Station. The transaction closed in September 2022 and, in October 2022, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover the related costs. The filing reflected an increase in annual revenues of $34 million, or 0.6%, effective with November 2022 billings. In 2020, the Alabama PSC approved a CCN authorizing Alabama Power to complete the acquisition of the Central Alabama Generating Station, which occurred in August 2020. Through May 2023, Alabama Power recovered substantially all costs associated with the Central Alabama Generating Station through Rate RSE, offset by revenues from a power sales agreement. Beginning in July 2022, fuel costs associated with Central Alabama Generating Station are being recovered through Rate ECR. On March 24, 2023, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover costs associated with the acquisition of the Central Alabama Generating Station. The filing reflected an annual increase in retail revenues of $78 million, or 1.1%, effective with June 2023 billings. On May 24, 2023, the Central Alabama Generating Station was placed into retail service. The Alabama PSC's 2020 CCN also authorized Alabama Power to construct an approximately 720-MW combined cycle facility at Alabama Power's Plant Barry (Plant Barry Unit 8) and the recovery of estimated in-service costs. On November 1, 2023, the unit was placed in service. On December 1, 2023, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover the related costs. The filing reflected an annual increase in retail revenues of $91 million, or 1.4%, effective with January 2024 billings. Rate CNP PPA Rate CNP PPA allows for the recovery of Alabama Power's retail costs associated with certificated PPAs. Revenues for Rate CNP PPA, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factors will have no significant effect on Southern Company's or Alabama Power's revenues or net income but will affect annual cash flow. No adjustments to Rate CNP PPA occurred during the period 2021 through 2023 and no adjustment is expected for 2024. At December 31, 2023 and 2022, Alabama Power had an under recovered Rate CNP PPA balance of $103 million and $120 million, respectively, of which $18 million and $18 million, respectively, is included in other regulatory assets, current and $85 million and $102 million, respectively, is included in other regulatory assets, deferred on the balance sheet. Rate CNP Compliance Rate CNP Compliance allows for the recovery of Alabama Power's retail costs associated with laws, regulations, and other such mandates directed at the utility industry involving the environment, security, reliability, safety, sustainability, or similar considerations impacting Alabama Power's facilities or operations. Rate CNP Compliance is based on forward-looking information and provides for the recovery of these costs pursuant to factors that are calculated and submitted to the Alabama PSC by December 1 with rates effective for the following calendar year. Compliance costs to be recovered include operations and maintenance expenses, depreciation, and a return on certain invested capital. Revenues for Rate CNP Compliance, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factors will have no significant effect on Southern Company's or Alabama Power's revenues or net income, but will affect annual cash flow. Changes in Rate CNP Compliance-related operations and maintenance expenses and depreciation generally will have no effect on net income. In November 2021, December 2022, and December 2023, Alabama Power submitted calculations to the Alabama PSC associated with its cost of complying with governmental mandates for the following calendar year, as provided under Rate CNP Compliance. The 2021 filing reflected a projected under recovered retail revenue requirement of approximately $59 million. In December 2021, the Alabama PSC issued a consent order that Alabama Power leave the 2021 Rate CNP Compliance factors in effect for 2022, with any prior year under collected amount deemed recovered before any current year amounts are recovered and any remaining under recovery reflected in the 2022 filing. The 2022 filing reflected a $255 million, or 3.7%, annual increase effective with January 2023 billings, primarily due to updated depreciation rates. The 2023 filing reflected a $23 million, or 0.3%, annual decrease effective with January 2024 billings. At December 31, 2023, Alabama Power had an under recovered Rate CNP Compliance balance of $33 million, of which $8 million is included in other regulatory assets, current and $25 million is included in other regulatory assets, deferred on the balances sheet, compared to an under recovered balance at December 31, 2022 of $47 million included in other regulatory assets, current on the balance sheet. Rate CNP Depreciation In December 2022, the Alabama PSC approved Rate CNP Depreciation, which allows Alabama Power to recover changes in depreciation resulting from updates to certain depreciation rates, excluding any depreciation recovered through Rate CNP New Plant, Rate CNP Compliance, or costs associated with the capitalization of asset retirement costs. Rate CNP Depreciation resulted in an annual revenue increase of approximately $318 million, or 4.6%, effective with January 2023 billings. See "Excess Accumulated Deferred Income Tax Accounting Order" herein for information related to 2023 customer bill credits approved by the Alabama PSC. Rate ECR Rate ECR recovers Alabama Power's retail energy costs based on an estimate of future energy costs and the current over or under recovered balance. Revenues recognized under Rate ECR and recorded on the financial statements are adjusted for the difference in actual recoverable fuel costs and amounts billed in current regulated rates. The difference in the recoverable fuel costs and amounts billed gives rise to the over or under recovered amounts recorded as regulatory assets or liabilities. Alabama Power, along with the Alabama PSC, continually monitors the over or under recovered cost balance to determine whether an adjustment to billing rates is required. Changes in the Rate ECR factor have no significant effect on Southern Company's or Alabama Power's net income but will impact the related operating cash flows. The Alabama PSC may approve billing rates under Rate ECR of up to 5.910 cents per KWH. The Alabama PSC approved adjustments to Rate ECR from 1.960 cents per KWH to 2.557 cents per KWH, or approximately $310 million annually, effective with August 2022 billings and from 2.557 cents per KWH to 3.510 cents per KWH, or approximately $500 million annually, effective with December 2022 billings. On November 9, 2023, the Alabama PSC approved a decrease to Rate ECR from 3.510 cents per KWH to 3.270 cents per KWH, or approximately $126 million annually, effective with December 2023 billings. The rate will adjust to 5.910 cents per KWH in January 2025 absent a further order from the Alabama PSC. At December 31, 2023 and 2022, Alabama Power's under recovered fuel costs totaled $246 million and $622 million, respectively, of which $246 million and $102 million, respectively, is included in regulatory assets – under recovered retail fuel clause revenues and $520 million of the December 31, 2022 balance is included in other regulatory assets, deferred on the balance sheets. These classifications are based on estimates, which include such factors as weather, generation availability, energy demand, and the price of energy. A change in any of these factors could have a significant impact on the timing of any recovery or return of fuel costs. Software Accounting Order The Alabama PSC authorizes Alabama Power to establish a regulatory asset for operations and maintenance costs associated with software implementation projects. The regulatory asset is amortized ratably over the life of the related software. At December 31, 2023 and 2022, the regulatory asset balance totaled $59 million and $46 million, respectively, and is included in other regulatory assets, deferred on the balance sheet. Plant Greene County Alabama Power jointly owns Plant Greene County with an affiliate, Mississippi Power. See Note 5 under "Joint Ownership Agreements" for additional information. In 2021, the Mississippi PSC concluded its review of Mississippi Power's 2021 IRP, which included a schedule to retire Mississippi Power's 40% ownership interest in Plant Greene County Units 1 and 2 in December 2025 and 2026, respectively, consistent with each unit's remaining useful life. Alabama Power and Mississippi Power have continued to evaluate operating conditions and business needs relevant to the anticipated retirement of Plant Greene County and now expect the units to remain in service beyond the previously indicated dates. The Plant Greene County unit retirements require the completion by Alabama Power of transmission and system reliability improvements, as well as agreement by Alabama Power. The ultimate outcome of this matter cannot be determined at this time. See "Mississippi Power – Integrated Resource Plan" herein for additional information. Rate NDR Based on an order from the Alabama PSC, Alabama Power maintains a reserve for operations and maintenance expenses to cover the cost of damages from major storms to its transmission and distribution facilities. The order approves a separate monthly Rate NDR charge to customers consisting of two components. The first component is intended to establish and maintain a reserve balance for future storms and is an on-going part of customer billing. When the reserve balance falls below $50 million, a reserve establishment charge will be activated (and the on-going reserve maintenance charge concurrently suspended) until the reserve balance reaches $75 million. The second component of the Rate NDR charge is intended to allow recovery of any existing deferred storm-related operations and maintenance costs and any future reserve deficits over a 48-month period (24-month period prior to modifications approved by the Alabama PSC in July 2022). The Alabama PSC order gives Alabama Power authority to record a deficit balance in the NDR when costs of storm damage exceed any established reserve balance. The maximum total Rate NDR charge was limited to $10.00 per month per non-residential customer account and $5.00 per month per residential customer account through July 12, 2022. Subsequently, modifications approved by the Alabama PSC replaced the maximum total Rate NDR charge with a maximum charge to recover a deficit of $5 per month per non-residential customer account and $2.50 per month per residential customer account. Alabama Power has the authority, based on an order from the Alabama PSC, to accrue certain additional amounts as circumstances warrant, which can be used to offset storm charges. Alabama Power made an additional accrual of $65 million in 2021. Alabama Power collected approximately $12 million, $14 million, and $6 million in 2023, 2022, and 2021, respectively, under Rate NDR. Beginning with August 2022 billings, the reserve establishment charge was suspended and the reserve maintenance charge was activated as a result of the NDR balance exceeding $75 million. Alabama Power expects to collect approximately $12 million annually under Rate NDR unless the NDR balance falls below $50 million. At December 31, 2023 and 2022, the NDR balance was $76 million and $97 million, respectively, and is included in other regulatory liabilities, deferred on the balance sheets. As revenue from the Rate NDR charge is recognized, an equal amount of operations and maintenance expenses related to the NDR will also be recognize

CONTINGENCIES, COMMITMENTS, AND

CONTINGENCIES, COMMITMENTS, AND GUARANTEES	12 Months Ended
CONTINGENCIES, COMMITMENTS, AND GUARANTEES	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES, COMMITMENTS, AND GUARANTEES	CONTINGENCIES, COMMITMENTS, AND GUARANTEES General Litigation Matters The Registrants are involved in various matters being litigated and regulatory matters. The ultimate outcome of such pending or potential litigation or regulatory matters against each Registrant and any subsidiaries cannot be determined at this time; however, for current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, arising from such current proceedings would have a material effect on such Registrant's financial statements. The Registrants intend to dispute the allegations raised in and vigorously defend against the pending legal challenges discussed below; however, the ultimate outcome of these matters cannot be determined at this time. Southern Company and Mississippi Power In 2010, the DOE, through a cooperative agreement with SCS, agreed to fund $270 million of the Kemper County energy facility through the grants awarded to the project by the DOE under the Clean Coal Power Initiative Round 2. In 2016, additional DOE grants in the amount of $137 million were awarded to the Kemper County energy facility. In 2018, Mississippi Power filed with the DOE its request for property closeout certification under the contract related to the $387 million of total grants received. In 2020, Mississippi Power and Southern Company executed an agreement with the DOE completing Mississippi Power's request, which enabled Mississippi Power to proceed with full dismantlement of the abandoned gasifier-related assets and site restoration activities. In connection with the DOE closeout discussions, in 2019, the Civil Division of the Department of Justice informed Southern Company and Mississippi Power of a civil investigation related to the DOE grants. On August 4, 2023, the U.S. District Court for the Northern District of Georgia unsealed a civil action in which defendants Southern Company, SCS, and Mississippi Power are alleged to have violated certain provisions of the False Claims Act by fraudulently inducing the DOE to disburse funds pursuant to the grants. The federal government declined to intervene in the action. On October 30, 2023, the plaintiff, a former SCS employee, filed an amended complaint, again alleging certain violations of the False Claims Act. The plaintiff seeks to recover all damages incurred personally and on behalf of the government caused by the defendants' alleged violations, as well as treble damages and attorneys' fees, among other relief. The ultimate outcome of this matter cannot be determined at this time; however, an adverse outcome could have a material impact on Southern Company's and Mississippi Power's financial statements. Alabama Power In September 2022, Mobile Baykeeper filed a citizen suit in the U.S. District Court for the Southern District of Alabama alleging that Alabama Power's plan to close the Plant Barry ash pond utilizing a closure-in-place methodology violates the Resource Conservation and Recovery Act (RCRA) and regulations governing CCR. Among other relief requested, Mobile Baykeeper sought a declaratory judgment that the RCRA and regulations governing CCR were being violated, preliminary and injunctive relief to prevent implementation of Alabama Power's closure plan and the development of a closure plan that satisfies regulations governing CCR requirements. In December 2022, Alabama Power filed a motion to dismiss the case. On January 4, 2024, the lawsuit was dismissed without prejudice by the U.S. District Court judge. On February 1, 2024, the plaintiff filed a motion to reconsider. On January 31, 2023, the EPA issued a Notice of Potential Violations associated with Alabama Power's plan to close the Plant Barry ash pond. Alabama Power has affirmed to the EPA its position that it is in compliance with CCR requirements. The ultimate outcome of this matter cannot be determined at this time but could have a material impact on Alabama Power's ARO estimates and cash flows. See Note 6 for a discussion of Alabama Power's ARO liabilities. Georgia Power In July 2020, a group of individual plaintiffs filed a complaint, which was amended in December 2022, in the Superior Court of Fulton County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer has impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs seek an unspecified amount of monetary damages including punitive damages, a medical monitoring fund, and injunctive relief. In December 2022, the Superior Court of Fulton County, Georgia granted Georgia Power's motion to transfer the case to the Superior Court of Monroe County, Georgia. On May 9, 2023, the Superior Court of Monroe County, Georgia denied Georgia Power's motion to dismiss the case for lack of subject matter jurisdiction. On July 27, 2023, the Superior Court of Monroe County, Georgia denied the remaining motions to dismiss certain claims and plaintiffs that Georgia Power filed at the outset of the case. In October 2021, February 2022, and January 2023, a total of eight additional complaints were filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that releases from Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs sought an unspecified amount of monetary damages including punitive damages. After Georgia Power removed these cases to the U.S. District Court for the Middle District of Georgia, the plaintiffs voluntarily dismissed their complaints without prejudice in November 2022 and January 2023. On May 12, 2023, the plaintiffs in the cases originally filed in October 2021, February 2022, and January 2023 refiled their eight complaints in the Superior Court of Monroe County, Georgia. Also on May 12, 2023, a new complaint was filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries. The plaintiff seeks an unspecified amount of monetary damages, including punitive damages. On May 18, 2023, Georgia Power removed all of these cases to the U.S. District Court for the Middle District of Georgia. The plaintiffs are requesting the court remand the cases back to the Superior Court of Monroe County, Georgia. The amount of possible loss, if any, from these matters cannot be estimated at this time. Mississippi Power In 2018, Ray C. Turnage and 10 other individual plaintiffs filed a putative class action complaint against Mississippi Power and the three then-serving members of the Mississippi PSC in the U.S. District Court for the Southern District of Mississippi, which was amended in March 2019 to include four additional plaintiffs. Mississippi Power received Mississippi PSC approval in 2013 to charge a mirror CWIP rate premised upon including in its rate base pre-construction and construction costs for the Kemper IGCC prior to placing the Kemper IGCC into service. The Mississippi Supreme Court reversed that approval and ordered Mississippi Power to refund the amounts paid by customers under the previously-approved mirror CWIP rate. The plaintiffs allege that the initial approval process, and the amount approved, were improper and make claims for gross negligence, reckless conduct, and intentional wrongdoing. They also allege that Mississippi Power underpaid customers by up to $23.5 million in the refund process by applying an incorrect interest rate. The plaintiffs seek to recover, on behalf of themselves and their putative class, actual damages, punitive damages, pre-judgment interest, post-judgment interest, attorney's fees, and costs. The district court dismissed the amended complaint; however, in March 2020, the plaintiffs filed a motion seeking to name the new members of the Mississippi PSC, the Mississippi Development Authority, and Southern Company as additional defendants and add a cause of action against all defendants based on a dormant commerce clause theory under the U.S. Constitution. In July 2020, the plaintiffs filed a motion for leave to file a third amended complaint, which included the same federal claims as the proposed second amended complaint, as well as several additional state law claims based on the allegation that Mississippi Power failed to disclose the annual percentage rate of interest applicable to refunds. In November 2020, the district court denied each of the plaintiffs' pending motions and entered final judgment in favor of Mississippi Power. In January 2021, the district court denied further motions by the plaintiffs to vacate the judgment and to file a revised second amended complaint. In February 2021, the plaintiffs filed a notice of appeal with the U.S. Court of Appeals for the Fifth Circuit. In March 2022, the U.S. Court of Appeals for the Fifth Circuit issued an opinion affirming the dismissal of the claims against the Mississippi PSC defendants but reversing the dismissal of the claims against Mississippi Power. In May 2022, the U.S. Court of Appeals for the Fifth Circuit denied a petition by Mississippi Power for a rehearing en banc and remanded the case to the U.S. District Court for the Southern District of Mississippi for further proceedings. In June 2022, Mississippi Power filed with the trial court a motion to dismiss the complaint with prejudice, which was granted on March 15, 2023. On March 28, 2023, the plaintiffs filed a notice of appeal with the U.S. Court of Appeals for the Fifth Circuit. On December 14, 2023, the U.S. Court of Appeals for the Fifth Circuit affirmed the district court's order dismissing the plaintiffs' complaint against Mississippi Power. On December 28, 2023, the plaintiffs filed a petition for panel rehearing, which was denied on January 10, 2024. The plaintiffs have until April 9, 2024 to file a petition for writ of certiorari with the U.S. Supreme Court. The ultimate outcome of this matter cannot be determined at this time. Southern Power In July 2021, Southern Power and certain of its subsidiaries filed an arbitration demand with the American Arbitration Association against First Solar Electric, LLC (First Solar) for defective design of actuators on trackers and inverters installed by First Solar under the engineering, procurement, and construction agreements associated with five solar projects owned by Southern Power and partners and managed by Southern Power. In February 2023, arbitration hearings concluded. In July 2023, an interim award of approximately $36 million was entered in favor of Southern Power and was subsequently received in September 2023. The interim award included $18 million representing recovery of losses associated with replacement costs, penalty payments, and lost revenues previously incurred. This recovery is reflected in Southern Power's 2023 statement of income as an $11 million reduction to other operations and maintenance expense and a $7 million increase in other revenues, with $6 million allocated through noncontrolling interests to Southern Power's partners. The remaining $18 million in award proceeds received in excess of the losses incurred is recognized on the balance sheet at December 31, 2023 as restricted cash and a liability to fund future replacement costs. In November 2023, the final award was issued and Southern Power filed for confirmation of the final award in the Delaware Court of Chancery. In December 2023, First Solar filed a motion to dismiss the confirmation and, in February 2024, filed a petition to vacate the arbitration award in the Supreme Court of New York County, New York. The ultimate outcome of this matter cannot be determined at this time. Environmental Remediation The Southern Company system must comply with environmental laws and regulations governing the handling and disposal of waste and releases of hazardous substances. Under these various laws and regulations, the Southern Company system could incur substantial costs to clean up affected sites. The traditional electric operating companies and the natural gas distribution utilities conduct studies to determine the extent of any required cleanup and have recognized the estimated costs to clean up known impacted sites in the financial statements. A liability for environmental remediation costs is recognized only when a loss is determined to be probable and reasonably estimable and is reduced as expenditures are incurred. The traditional electric operating companies and the natural gas distribution utilities in Illinois and Georgia have each received authority from their respective state PSCs or other applicable state regulatory agencies to recover approved environmental remediation costs through regulatory mechanisms. Any difference between the liabilities accrued and costs recovered through rates is deferred as a regulatory asset or liability. These regulatory mechanisms are adjusted annually or as necessary within limits approved by the state PSCs or other applicable state regulatory agencies. Georgia Power has been designated or identified as a potentially responsible party at sites governed by the Georgia Hazardous Site Response Act and/or by the federal Comprehensive Environmental Response, Compensation, and Liability Act, and assessment and potential cleanup of such sites is expected. For 2023, 2022, and 2021, Georgia Power recovered approximately $5 million, $12 million, and $12 million, respectively, through the ECCR tariff for environmental remediation. Southern Company Gas is subject to environmental remediation liabilities associated with 40 former manufactured gas plant sites in four different states. Southern Company Gas' accrued environmental remediation liability at December 31, 2023 and 2022 was based on the estimated cost of environmental investigation and remediation associated with these sites. At December 31, 2023 and 2022, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power and Mississippi Power did not have environmental remediation liabilities at December 31, 2023 or 2022. Southern Company Georgia Southern Company Gas (in millions) December 31, 2023: Environmental remediation liability: Other current liabilities $ 44 $ 14 $ 30 Accrued environmental remediation 192 — 192 Under recovered environmental remediation costs: Other regulatory assets, current $ 45 $ 5 $ 40 Other regulatory assets, deferred 210 15 195 December 31, 2022: Environmental remediation liability: Other current liabilities $ 65 $ 15 $ 49 Accrued environmental remediation 207 — 207 Under recovered environmental remediation costs: Other regulatory assets, current $ 59 $ 5 $ 54 Other regulatory assets, deferred 235 20 215 The ultimate outcome of these matters cannot be determined at this time; however, as a result of the regulatory treatment for environmental remediation expenses described above, the final disposition of these matters is not expected to have a material impact on the financial statements of the applicable Registrants. Nuclear Fuel Disposal Costs Acting through the DOE and pursuant to the Nuclear Waste Policy Act of 1982, the U.S. government entered into contracts with Alabama Power and Georgia Power that required the DOE to take title to and dispose of spent nuclear fuel generated at Plants Farley, Hatch, and Vogtle Units 1 and 2 beginning no later than January 31, 1998. The DOE has yet to commence performance of its contractual and statutory obligation to dispose of spent nuclear fuel. Consequently, Alabama Power and Georgia Power pursued and continue to pursue legal remedies against the U.S. government for its partial breach of contract. In 2014, Alabama Power and Georgia Power filed their third round of lawsuits against the U.S. government in the Court of Federal Claims, seeking damages for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2011 through December 31, 2013. The damage period was subsequently extended to December 31, 2014. In 2019, the Court of Federal Claims granted Alabama Power's and Georgia Power's motion for summary judgment on damages not disputed by the U.S. government, awarding those undisputed damages to Alabama Power and Georgia Power. However, those undisputed damages are not collectible until the court enters final judgment on the remaining damages. In 2017, Alabama Power and Georgia Power filed their fourth round of lawsuits against the U.S. government in the Court of Federal Claims, seeking damages for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2015 through December 31, 2017. In 2020, Alabama Power and Georgia Power filed amended complaints in those fourth-round lawsuits adding damages incurred from January 1, 2018 to December 31, 2019 to the claim period. The outstanding claims for the period January 1, 2011 through December 31, 2019 total $106 million and $128 million for Alabama Power and Georgia Power (based on its ownership interests), respectively. Damages will continue to accumulate until the issue is resolved, the U.S. government disposes of Alabama Power's and Georgia Power's spent nuclear fuel pursuant to its contractual obligations, or alternative storage is otherwise provided. No amounts have been recognized in the financial statements as of December 31, 2023 for any potential recoveries from the pending lawsuits. The final outcome of these matters cannot be determined at this time. However, Alabama Power and Georgia Power expect to credit any recoveries for the benefit of customers in accordance with direction from their respective PSC; therefore, no material impact on Southern Company's, Alabama Power's, or Georgia Power's net income is expected. On-site dry spent fuel storage facilities are operational at all three plants and can be expanded to accommodate spent fuel through the expected life of each plant. Nuclear Insurance Under the Price-Anderson Amendments Act (Act), Alabama Power and Georgia Power maintain agreements of indemnity with the NRC that, together with private insurance, cover third-party liability arising from any nuclear incident occurring at the companies' nuclear power plants. The Act provides funds up to $16.2 billion for public liability claims that could arise from a single nuclear incident. Each nuclear plant is insured against this liability to a maximum of $450 million by American Nuclear Insurers (ANI), with the remaining coverage provided by a mandatory program of deferred premiums that could be assessed, after a nuclear incident, against all owners of commercial nuclear reactors. A company could be assessed up to $166 million per incident for each licensed reactor it operates but not more than an aggregate of $25 million per incident to be paid in a calendar year for each reactor. Such maximum assessment, excluding any applicable state premium taxes, for Alabama Power and Georgia Power, based on its ownership and buyback interests in all licensed reactors, is $332 million and $473 million, respectively, per incident, but not more than an aggregate of $49 million and $71 million, respectively, to be paid for each incident in any one year. Both the maximum assessment per reactor and the maximum yearly assessment are adjusted for inflation at least every five years. The next scheduled adjustment is due no later than November 1, 2028. See Note 5 under "Joint Ownership Agreements" for additional information on joint ownership agreements. Alabama Power and Georgia Power are members of Nuclear Electric Insurance Limited (NEIL), a mutual insurer established to provide property damage insurance in an amount up to $1.5 billion for members' operating nuclear generating facilities. Additionally, both companies have NEIL policies that currently provide decontamination, excess property insurance, and premature decommissioning coverage up to $1.25 billion for nuclear losses and policies providing coverage up to $750 million for non-nuclear losses in excess of the $1.5 billion primary coverage. NEIL also covers the additional costs that would be incurred in obtaining replacement power during a prolonged accidental outage at a member's nuclear plant. Members can purchase this coverage, subject to a deductible waiting period of up to 26 weeks, with a maximum per occurrence per unit limit of $490 million. After the deductible period, weekly indemnity payments would be received until either the unit is operational or until the limit is exhausted. Alabama Power and Georgia Power each purchase limits based on the projected full cost of replacement power, subject to ownership limitations, and have each elected a 12-week deductible waiting period for each nuclear plant. A builders' risk property insurance policy has been purchased from NEIL for the construction of Plant Vogtle Unit 4. This policy provides the Vogtle Owners up to $2.75 billion for accidental property damage occurring during construction. Under each of the NEIL policies, members are subject to assessments each year if losses exceed the accumulated funds available to the insurer. The maximum annual assessments for Alabama Power and Georgia Power as of December 31, 2023 under the NEIL policies would be $54 million and $89 million, respectively. Claims resulting from terrorist acts and cyber events are covered under both the ANI and NEIL policies (subject to normal policy limits). The maximum aggregate that NEIL will pay for all claims resulting from terrorist acts and cyber events in any 12-month period is $3.2 billion each, plus such additional amounts NEIL can recover through reinsurance, indemnity, or other sources. For all on-site property damage insurance policies for commercial nuclear power plants, the NRC requires that the proceeds of such policies shall be dedicated first for the sole purpose of placing the reactor in a safe and stable condition after an accident. Any remaining proceeds are to be applied next toward the costs of decontamination and debris removal operations ordered by the NRC, and any further remaining proceeds are to be paid either to the applicable company or to its debt trustees as may be appropriate under the policies and applicable trust indentures. In the event of a loss, the amount of insurance available might not be adequate to cover property damage and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered from customers, would be borne by Alabama Power or Georgia Power, as applicable, and could have a material effect on Southern Company's, Alabama Power's, and Georgia Power's financial condition and results of operations. Other Matters Traditional Electric Operating Companies In April 2019, Bellsouth Telecommunications d/b/a AT&T Alabama (AT&T) filed a complaint against Alabama Power with the FCC alleging that the pole rental rate AT&T is required to pay pursuant to the parties' joint use agreement is unjust and unreasonable under federal law. The complaint sought a new rate and approximately $87 million in refunds of alleged overpayments for the preceding six years. In August 2019, the FCC stayed the case in favor of arbitration, which AT&T has not pursued. The joint use agreement remains in effect. The ultimate outcome of this matter cannot be determined at this time, but an adverse outcome could have a material impact on the financial statements of Southern Company and Alabama Power. Georgia Power and Mississippi Power have joint use agreements with other AT&T affiliates. Mississippi Power Kemper County Energy Facility In 2021, 2022, and 2023, Mississippi Power recorded charges to income associated with abandonment and related closure costs and ongoing period costs, net of salvage proceeds, for the mine and gasifier-related assets at the Kemper County energy facility. These charges, including related tax impacts, totaled $11 million pre-tax ($8 million after tax) in 2021, $15 million pre-tax ($12 million after tax) in 2022, and $17 million pre-tax ( $12 million after tax) in 2023. The pre-tax charges are included in other operations and maintenance expenses on the statements of income. Dismantlement of the abandoned gasifier-related assets and site restoration activities are expected to be completed by 2026 . Additional pre-tax period costs associated with dismantlement and site restoration activities, including related costs for compliance and safety, ARO accretion, and property taxes, net of salvage, are estimated to total approximately $15 million annually through 2025 . Mississippi Power owns the lignite mine located around the Kemper County energy facility site. As a result of the abandonment of the Kemper IGCC, final mine reclamation began in 2018 and was substantially completed in 2020, with monitoring expected to continue through 2028. As the mining permit holder, Liberty Fuels Company, LLC, a wholly-owned subsidiary of The North American Coal Corporation, has a legal obligation to perform mine reclamation and Mississippi Power has a contractual obligation to fund all reclamation activities. See Note 6 for additional information. See "General Litigation Matters – Southern Company and Mississippi Power" herein for information regarding litigation associated with the Kemper County energy facility. Plant Daniel In conjunction with Southern Company's 2019 sale of Gulf Power, NextEra Energy held back $75 million of the purchase price pending Mississippi Power and NextEra Energy negotiating a mutually acceptable revised operating agreement for Plant Daniel. In July 2022, the co-owners executed a revised operating agreement and Southern Company subsequently received the remaining $75 million of the purchase price. The dispatch procedures in the revised operating agreement for the two jointly-owned coal units at Plant Daniel resulted in Mississippi Power designating one of the two units as primary and the other as secondary in lieu of each company separately owning 100% of a single generating unit. Mississippi Power did not exercise an option to purchase its co-owner's ownership interest for $1 on January 15, 2024. The revised operating agreement did not have a material impact on Mississippi Power's financial statements. See Note 2 under "M ississippi Power – Integrated Resource Plan" for additional information on Plant Daniel. Commitments To supply a portion of the fuel requirements of the Southern Company system's electric generating plants, the Southern Company system has entered into various long-term commitments not recognized on the balance sheets for the procurement and delivery of fossil fuel and, for Alabama Power and Georgia Power, nuclear fuel. The majority of the Registrants' fuel expense for the periods presented was purchased under long-term commitments. Each Registrant expects that a substantial amount of its future fuel needs will continue to be purchased under long-term commitments. Georgia Power has commitments, in the form of capacity purchases, regarding a portion of a 5% interest in the original cost of Plant Vogtle Units 1 and 2 owned by MEAG Power that are in effect until the later of the retirement of the plant or the latest stated maturity date of MEAG Power's bonds issued to finance such ownership interest. The payments for capacity are required whether or not any capacity is available. Portions of the capacity payments made to MEAG Power for its Plant Vogtle Units 1 and 2 investment relate to costs in excess of Georgia Power's allowed investment for ratemaking purposes. The present value of these portions at the time of the disallowance was written off. Generally, the cost of such capacity is included in purchased power in Southern Company's statements of income and in purchased power, non-affiliates in Georgia Power's statements of income. Georgia Power's capacity payments related to this commitment totaled $3 million, $4 million, and $6 million in 2023, 2022, and 2021, respectively. At December 31, 2023, Georgia Power's estimated long-term obligations related to this commitment totaled $39 million, consisting of $4 million annually for 2024 and 2025, $2 million annually for 2026 through 2028, and $25 million thereafter. See Note 9 for information regarding PPAs accounted for as leases. Southern Company Gas has commitments for pipeline charges, storage capacity, and gas supply, including charges recoverable through natural gas cost recovery mechanisms or, alternatively, billed to marketers selling retail natural gas. Gas supply commitments include amounts for gas commodity purchases associated with Nicor Gas and SouthStar of 38 million mmBtu at floating gas prices calculated using forward natural gas prices at December 31, 2023 and valued at $98 million. Southern Company Gas provides guarantees to certain gas suppliers for certain of its subsidiaries in support of payment obligations. Southern Company Gas' expected future contractual obligations for pipeline charges, storage capacity, and gas supply that are not recognized on the balance sheets at December 31, 2023 were as follows: Pipeline Charges, Storage Capacity, and Gas Supply (in millions) 2024 $ 587 2025 432 2026 231 2027 148 2028 103 Thereafter 785 Total $ 2,286 Guarantees SCS may enter into various types of wholesale energy and natural gas contracts acting as an agent for the traditional electric operating companies and Southern Power. Under these agreements, each of the traditional electric operating companies and Southern Power may be jointly and severally liable. Accordingly, Southern Company has entered into keep-well agreements with each of the traditional electric operating companies to ensure they will not subsidize or be responsible for any costs, losses, liabilities, or damages resulting from the inclusion of Southern Power as a contracting party under these agreements. Alabama Power has guaranteed a $100 million principal amount long-term bank loan SEGCO entered into in 2018 and subsequently extended and amended. Georgia Power has agreed to reimburse Alabama Power for the portion of such obligation corresponding to Georgia Power's proportionate ownership of SEGCO's stock if Alabama Power is called upon to make such payment under its guarantee. At December 31, 2023, the capitalization of SEGCO consisted of $69 million of equity and $100 million of long-term debt that matures in November 2024, on which the annual interest requirement is derived from a variable rate index. SEGCO had no short-term debt outstanding at December 31, 2023. See Note 7 under "SEGCO" for additional information. As discussed in Note 9, Alabama Power and Georgia Power have entered into certain residual value guarantees related to railcar leases.

REVENUE FROM CONTRACTS WITH CUS

REVENUE FROM CONTRACTS WITH CUSTOMERS	12 Months Ended
REVENUE FROM CONTRACTS WITH CUSTOMERS	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
REVENUE FROM CONTRACTS WITH CUSTOMERS	REVENUE FROM CONTRACTS WITH CUSTOMERS The Registrants generate revenues from a variety of sources, some of which are not accounted for as revenue from contracts with customers, such as leases, derivatives, and certain cost recovery mechanisms. See Note 1 under "Revenues" for additional information on the revenue policies of the Registrants. See Notes 9 and 14 for additional information on revenue accounted for under lease and derivative accounting guidance, respectively. The following table disaggregates revenue from contracts with customers for the periods presented: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Operating revenues Retail electric revenues Residential $ 7,309 $ 2,904 $ 4,105 $ 300 $ — $ — Commercial 5,860 1,928 3,624 308 — — Industrial 3,613 1,721 1,558 334 — — Other 112 12 91 9 — — Total retail electric revenues 16,894 6,565 9,378 951 — — Natural gas distribution revenues Residential 1,981 — — — — 1,981 Commercial 505 — — — — 505 Transportation 1,184 — — — — 1,184 Industrial 45 — — — — 45 Other 324 — — — — 324 Total natural gas distribution revenues 4,039 — — — — 4,039 Wholesale electric revenues PPA energy revenues 1,107 234 87 20 790 — PPA capacity revenues 624 156 51 45 376 — Non-PPA revenues 250 65 35 407 409 — Total wholesale electric revenues 1,981 455 173 472 1,575 — Other natural gas revenues Gas marketing services 528 — — — — 528 Other natural gas revenues 31 — — — — 31 Total natural gas revenues 559 — — — — 559 Other revenues 1,355 213 578 39 55 — Total revenue from contracts with customers 24,828 7,233 10,129 1,462 1,630 4,598 Other revenue sources (a) 425 (183) (11) 12 559 104 Total operating revenues $ 25,253 $ 7,050 $ 10,118 $ 1,474 $ 2,189 $ 4,702 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Operating revenues Retail electric revenues Residential $ 6,604 $ 2,638 $ 3,664 $ 302 $ — $ — Commercial 5,369 1,685 3,385 299 — — Industrial 3,764 1,507 1,921 336 — — Other 102 14 79 9 — — Total retail electric revenues 15,839 5,844 9,049 946 — — Natural gas distribution revenues Residential 2,843 — — — — 2,843 Commercial 763 — — — — 763 Transportation 1,186 — — — — 1,186 Industrial 84 — — — — 84 Other 342 — — — — 342 Total natural gas distribution revenues 5,218 — — — — 5,218 Wholesale electric revenues PPA energy revenues 2,274 489 130 16 1,673 — PPA capacity revenues 596 194 47 4 356 — Non-PPA revenues 250 200 30 690 740 — Total wholesale electric revenues 3,120 883 207 710 2,769 — Other natural gas revenues Gas marketing services 636 — — — — 636 Other natural gas revenues 51 — — — — 51 Total other natural gas revenues 687 — — — — 687 Other revenues 1,077 194 446 47 36 — Total revenue from contracts with customers 25,941 6,921 9,702 1,703 2,805 5,905 Other revenue sources (a) 3,338 896 1,882 (9) 564 57 Total operating revenues $ 29,279 $ 7,817 $ 11,584 $ 1,694 $ 3,369 $ 5,962 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2021 Operating revenues Retail electric revenues Residential $ 6,207 $ 2,467 $ 3,471 $ 269 $ — $ — Commercial 4,877 1,600 3,010 267 — — Industrial 3,067 1,386 1,391 290 — — Other 93 17 68 8 — — Total retail electric revenues 14,244 5,470 7,940 834 — — Natural gas distribution revenues Residential 1,799 — — — — 1,799 Commercial 470 — — — — 470 Transportation 1,038 — — — — 1,038 Industrial 49 — — — — 49 Other 269 — — — — 269 Total natural gas distribution revenues 3,625 — — — — 3,625 Wholesale electric revenues PPA energy revenues 1,122 184 95 11 854 — PPA capacity revenues 493 115 55 5 323 — Non-PPA revenues 236 170 21 401 398 — Total wholesale electric revenues 1,851 469 171 417 1,575 — Other natural gas revenues Wholesale gas services 2,168 — — — — 2,168 Gas marketing services 464 — — — — 464 Other natural gas revenues 36 — — — — 36 Total other natural gas revenues 2,668 — — — — 2,668 Other revenues 1,075 202 452 31 30 — Total revenue from contracts with customers 23,463 6,141 8,563 1,282 1,605 6,293 Other revenue sources (a) 3,349 272 697 40 611 1,786 Other adjustments (b) (3,699) — — — — (3,699) Total operating revenues $ 23,113 $ 6,413 $ 9,260 $ 1,322 $ 2,216 $ 4,380 (a) Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues (including those related to fuel costs ) that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies. (b) Other adjustments relate to the cost of Southern Company Gas' energy and risk management activities. Wholesale gas services revenues are presented net of the related costs of those activities on the statement of income. See Notes 15 and 16 under "Southern Company Gas" for information on the sale of Sequent and components of wholesale gas services' operating revenues, respectively. Contract Balances The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2023 and 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At December 31, 2023 $ 2,820 $ 821 $ 1,011 $ 90 $ 122 $ 684 At December 31, 2022 3,123 696 922 92 237 1,107 Contract Assets At December 31, 2023 $ 271 $ 2 $ 121 $ — $ — $ 56 At December 31, 2022 156 2 89 — — — Contract Liabilities At December 31, 2023 $ 116 $ — $ 1 $ — $ 4 $ — At December 31, 2022 45 4 9 — 1 — Contract assets for Georgia Power primarily relate to retail customer fixed bill programs, where the payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over a one-year contract term, and unregulated service agreements, where payment is contingent on project completion. Contract liabilities for Georgia Power primarily relate to cash collections recognized in advance of revenue for unregulated service agreements. Southern Company Gas' contract assets relate to work performed on an energy efficiency enhancement and upgrade contract with the U.S. General Services Administration. Southern Company Gas receives cash advances from a third-party financial institution to fund work performed, of which approximately $59 million had been received at December 31, 2023. These advances have been accounted for as long-term debt on the balance sheets. See Note 1 under "Affiliate Transactions" for additional information regarding the construction contract. At December 31, 2023 and 2022, Southern Company's unregulated distributed generation business had contract assets of $91 million and $65 million, respectively, and contract liabilities of $115 million and $32 million, respectively, for outstanding performance obligations. Revenues recognized in 2023 and 2022, which were included in contract liabilities at December 31, 2023 and 2022, respectively, were $36 million annually for Southern Company and immaterial for the other Registrants. Contract liabilities are primarily classified as current on the balance sheets as the corresponding revenues are generally expected to be recognized within one year. Remaining Performance Obligations The Subsidiary Registrants may enter into long-term contracts with customers in which revenues are recognized as performance obligations are satisfied over the contract term. For the traditional electric operating companies and Southern Power, these contracts primarily relate to PPAs whereby electricity and generation capacity are provided to a customer. The revenue recognized for the delivery of electricity is variable; however, certain PPAs include a fixed payment for fixed generation capacity over the term of the contract. For Southern Company Gas, these contracts primarily relate to the U.S. General Services Administration contract described above. Southern Company's unregulated distributed generation business also has partially satisfied performance obligations related to certain fixed price contracts. Revenues from contracts with customers related to these performance obligations remaining at December 31, 2023 are expected to be recognized as follows: 2024 2025 2026 2027 2028 Thereafter (in millions) Southern Company $ 940 $ 552 $ 338 $ 332 $ 323 $ 2,045 Alabama Power 23 9 — — — — Georgia Power 73 41 14 15 15 9 Mississippi Power 60 63 66 69 73 — Southern Power 379 301 299 306 297 2,041 Southern Company Gas 26 — — — — —

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT	12 Months Ended
PROPERTY, PLANT, AND EQUIPMENT	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT, AND EQUIPMENT	PROPERTY, PLANT, AND EQUIPMENT Property, plant, and equipment is stated at original cost or fair value at acquisition, as appropriate, less any regulatory disallowances and impairments. Original cost may include: materials; labor; minor items of property; appropriate administrative and general costs; payroll-related costs such as taxes, pensions, and other benefits; and the interest capitalized and/or cost of equity funds used during construction. The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2023 and 2022: At December 31, 2023: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 57,325 $ 16,584 $ 22,587 $ 2,909 $ 14,649 $ — Transmission 15,561 6,152 8,402 966 — — Distribution 26,482 9,775 15,380 1,327 — — General/other 6,305 2,918 3,001 321 41 — Electric utilities' plant in service 105,673 35,429 49,370 5,523 14,690 — Southern Company Gas: Natural gas transportation and distribution 17,798 — — — — 17,798 Storage facilities 1,565 — — — — 1,565 Other 1,477 — — — — 1,477 Southern Company Gas plant in service 20,840 — — — — 20,840 Other plant in service 1,915 — — — — — Total plant in service $ 128,428 $ 35,429 $ 49,370 $ 5,523 $ 14,690 $ 20,840 At December 31, 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 51,756 $ 15,920 $ 17,755 $ 2,826 $ 14,619 $ — Transmission 14,201 5,658 7,576 927 — — Distribution 24,200 9,154 13,819 1,228 — — General/other 5,806 2,740 2,729 273 39 — Electric utilities' plant in service 95,963 33,472 41,879 5,254 14,658 — Southern Company Gas: Natural gas transportation and distribution 16,810 — — — — 16,810 Storage facilities 1,553 — — — — 1,553 Other 1,360 — — — — 1,360 Southern Company Gas plant in service 19,723 — — — — 19,723 Other plant in service 1,843 — — — — — Total plant in service $ 117,529 $ 33,472 $ 41,879 $ 5,254 $ 14,658 $ 19,723 The cost of replacements of property, exclusive of minor items of property, is capitalized. The cost of maintenance, repairs, and replacement of minor items of property is charged to other operations and maintenance expenses as incurred or performed with the exception of nuclear refueling costs and certain maintenance costs including those described below. In accordance with orders from their respective state PSCs, Alabama Power and Georgia Power defer nuclear refueling outage operations and maintenance expenses to a regulatory asset when the charges are incurred. Alabama Power amortizes the costs over a subsequent 18-month period with Plant Farley's fall outage cost amortization beginning in January of the following year and spring outage cost amortization beginning in July of the same year. Georgia Power amortizes its costs over each unit's operating cycle, or 18 months for Plant Vogtle Units 1, 2, and 3 and 24 months for Plant Hatch Units 1 and 2. Georgia Power's amortization period begins the month the refueling outage starts. A portion of Mississippi Power's railway track maintenance costs is charged to fuel stock and recovered through Mississippi Power's fuel clause. The portion of Southern Company Gas' non-working gas used to maintain the structural integrity of natural gas storage facilities that is considered to be non-recoverable is depreciated, while the recoverable or retained portion is not depreciated. See Note 9 for information on finance lease right-of-use (ROU) assets, net, which are included in property, plant, and equipment. The Registrants have deferred certain implementation costs related to cloud hosting arrangements. At December 31, 2023 and 2022, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Deferred cloud implementation costs, net: At December 31, 2023 $ 325 $ 85 $ 99 $ 13 $ 15 $ 43 At December 31, 2022 345 81 108 14 18 54 Once a hosted software is placed into service, the related deferred costs are amortized on a straight-line basis over the remaining expected hosting arrangement term, including any renewal options that are reasonably certain of exercise. The amortization is reflected with the associated cloud hosting fees, which are generally reflected in other operations and maintenance expenses on the Registrants' statements of income. In 2023, amortization of deferred cloud implementation costs recognized was $46 million for Southern Company, $11 million for Alabama Power, $19 million for Georgia Power, $8 million for Southern Company Gas, and immaterial for the other Registrants. In 2022, amortization of deferred cloud implementation costs recognized was $29 million for Southern Company, $8 million for Alabama Power, $12 million for Georgia Power, and immaterial for the other Registrants. In 2021, amortization from deferred cloud implementation costs recognized was immaterial for all Registrants. See Note 2 under "Regulatory Assets and Liabilities" and "Alabama Power – Software Accounting Order" for information on deferrals of certain other operations and maintenance costs associated with software and cloud computing projects by the traditional electric operating companies and natural gas distribution utilities, as authorized by their respective state PSCs or applicable state regulatory agencies. Depreciation and Amortization The traditional electric operating companies' and Southern Company Gas' depreciation of the original cost of utility plant in service is provided primarily by using composite straight-line rates. The approximate rates for 2023, 2022, and 2021 are as follows: 2023 2022 2021 Alabama Power 4.1 % 2.7 % 2.7 % Georgia Power 3.8 % 3.3 % 3.3 % Mississippi Power 3.4 % 3.4 % 3.6 % Southern Company Gas 2.7 % 2.7 % 2.8 % Depreciation studies are conducted periodically to update the composite rates. These studies are filed with the respective state PSC and/or other applicable state and federal regulatory agencies for the traditional electric operating companies and the natural gas distribution utilities. Effective January 1, 2023, Alabama Power's and Georgia Power's depreciation rates were revised. See Note 2 for additional information. When property, plant, and equipment subject to composite depreciation is retired or otherwise disposed of in the normal course of business, its original cost, together with the cost of removal, less salvage, is charged to accumulated depreciation. For other property dispositions, the applicable cost and accumulated depreciation are removed from the balance sheet accounts, and a gain or loss is recognized. Minor items of property included in the original cost of the asset are retired when the related property unit is retired. At December 31, 2023 and 2022, accumulated depreciation for Southern Company and Southern Company Gas consisted of utility plant in service totaling $36.6 billion and $34.3 billion, respectively, for Southern Company and $5.3 billion and $5.1 billion, respectively, for Southern Company Gas, as well as other plant in service totaling $1.1 billion and $1.0 billion, respectively, for Southern Company and $210 million and $184 million, respectively, for Southern Company Gas. Other plant in service includes the non-utility assets of Southern Company Gas, as well as, for Southern Company, certain other non-utility subsidiaries. Depreciation of the original cost of other plant in service is provided primarily on a straight-line basis over estimated useful lives. Useful lives for Southern Company Gas's non-utility assets range from five Southern Power Southern Power applies component depreciation, where depreciation is computed principally by the straight-line method over the estimated useful life of the asset. Certain of Southern Power's generation assets related to natural gas-fired facilities are depreciated on a units-of-production basis, using hours or starts, to better match outage and maintenance costs to the usage of, and revenues from, these assets. The primary assets in Southern Power's property, plant, and equipment are generating facilities, which generally have estimated useful lives as follows: Southern Power Generating Facility Useful life Natural gas Up to 50 years Solar Up to 35 years Wind Up to 35 years When Southern Power's depreciable property, plant, and equipment is retired, or otherwise disposed of in the normal course of business, the applicable cost and accumulated depreciation is removed and a gain or loss is recognized in the statements of income. Southern Power reviews its estimated useful lives and salvage values on an ongoing basis. The results of these reviews could result in changes which could have a material impact on Southern Power's net income. Joint Ownership Agreements At December 31, 2023, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows: Facility (Type) Percent Plant in Service Accumulated CWIP (in millions) Alabama Power Greene County (natural gas) Units 1 and 2 60.0 % (a) $ 191 $ 113 $ 1 Plant Miller (coal) Units 1 and 2 91.8 (b) 2,156 778 40 Georgia Power Plant Hatch (nuclear) Units 1 and 2 50.1 % (c) $ 1,446 $ 659 $ 70 Plant Vogtle (nuclear) Units 1 and 2 45.7 (c) 3,664 2,331 62 Plant Vogtle (nuclear) Units 3 and 4 45.7 (c)(d) 4,613 19 3,232 Plant Scherer (coal) Units 1 and 2 8.4 (c) 287 123 2 Plant Scherer (coal) Unit 3 75.0 (c) 1,310 639 10 Rocky Mountain (pumped storage) 25.4 (e) 181 153 — Mississippi Power Greene County (natural gas) Units 1 and 2 40.0 % (a) $ 125 $ 80 $ — Plant Daniel (coal) Units 1 and 2 50.0 (f) 805 281 1 Southern Company Gas Dalton Pipeline (natural gas pipeline) 50.0 % (g) $ 271 $ 27 $ — (a) Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power. (b) Jointly owned with PowerSouth and operated and maintained by Alabama Power. (c) Georgia Power owns undivided interests in Plants Hatch, Vogtle, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and JEA. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third party claims related to these plants. (d) Unit 4 remains under construction. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (e) Jointly owned with OPC, which is the operator of the plant. (f) Jointly owned by FP&L and Mississippi Power. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 3 under "Other Matters – Mississippi Power – Plant Daniel" for additional information. (g) Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff. The Registrants' proportionate share of their jointly-owned facility operating expenses is included in the corresponding operating expenses in the statements of income and each Registrant is responsible for providing its own financing. Assets Subject to Lien Mississippi Power provides retail service to its largest retail customer, Chevron Products Company (Chevron), at its refinery in Pascagoula, Mississippi through at least 2038 in accordance with agreements approved by the Mississippi PSC. The agreements grant Chevron a security interest in the co-generation assets located at the refinery and owned by Mississippi Power, with a lease receivable balance of $147 million at December 31, 2023, that is exercisable upon the occurrence of (i) certain bankruptcy events or (ii) other events of default coupled with specific reductions in steam output at the facility and a downgrade of Mississippi Power's credit rating to below investment grade by two of the three rating agencies. See Note 9 under "Lessor" for additional information. See Note 8 under "Long-term Debt" for information regarding debt secured by certain assets of Georgia Power and Southern Company Gas.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
ASSET RETIREMENT OBLIGATIONS	Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
ASSET RETIREMENT OBLIGATIONS	ASSET RETIREMENT OBLIGATIONS AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets. The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally ash ponds. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle Units 1 through 3). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease. The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO. Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs. Details of the AROs included in the balance sheets are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power () (in millions) Balance at December 31, 2021 $ 11,687 $ 4,334 $ 6,824 $ 190 $ 131 Liabilities incurred 36 — 35 — — Liabilities settled (455) (205) (212) (20) — Accretion expense 406 158 231 6 6 Cash flow revisions (834) — (844) 3 7 Balance at December 31, 2022 $ 10,840 $ 4,287 $ 6,034 $ 179 $ 144 Liabilities incurred 90 — 90 — — Liabilities settled (617) (270) (304) (18) — Accretion expense 403 156 230 5 6 Cash flow revisions (399) (15) (385) 2 — Balance at December 31, 2023 $ 10,317 $ 4,158 $ 5,665 $ 168 $ 150 () Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. In December 2022, Georgia Power recorded a net decrease of approximately $780 million to its AROs related to the CCR Rule and the related state rule resulting from changes in estimates, including lower future inflation rates, higher discount rates, and timing of closure activities, as well as a change in closure methodology for one ash pond as approved in Georgia Power's 2022 IRP. Following initial criticality for Plant Vogtle Unit 3 on March 6, 2023, Georgia Power recorded AROs of approximately $90 million. Subsequent to December 31, 2023, Plant Vogtle Unit 4 achieved initial criticality, which will result in Georgia Power recording AROs of approximately $118 million during the first quarter 2024. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. In September 2023 and November 2023, Georgia Power recorded net decreases of approximately $175 million and $210 million, respectively, to its AROs related to the CCR Rule and the related state rule resulting from changes in estimates, including lower future inflation rates and the timing of closure activities. In June 2023, Alabama Power completed an updated decommissioning cost site study for Plant Farley. The estimated cost of decommissioning based on the study resulted in a decrease in Alabama Power's ARO liability of approximately $15 million. See "Nuclear Decommissioning" herein for additional information. The cost estimates for AROs related to the disposal of CCR are based on information at December 31, 2023 using various assumptions related to closure and post-closure costs, timing of future cash outlays, inflation and discount rates, and the potential methods for complying with the CCR Rule and the related state rules. The traditional electric operating companies have periodically updated, and expect to continue periodically updating, their related cost estimates and ARO liabilities for each CCR unit as additional information related to these assumptions becomes available. Some of these updates have been, and future updates may be, material. The cost estimates for Alabama Power are based on closure-in-place for all ash ponds. The cost estimates for Georgia Power and Mississippi Power are based on a combination of closure-in-place for some ash ponds and closure by removal for others. Additionally, the closure designs and plans in the States of Alabama and Georgia are subject to approval by environmental regulatory agencies. Absent continued recovery of ARO costs through regulated rates, results of operations, cash flows, and financial condition for Southern Company and the traditional electric operating companies could be materially impacted. The ultimate outcome of these matters cannot be determined at this time. See Note 3 under "General Litigation Matters – Alabama Power" for additional information. Nuclear Decommissioning The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers, neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities. Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis. Investment securities in the Funds for December 31, 2023 and 2022 were as follows: Southern Company Alabama Georgia (in millions) At December 31, 2023: Equity securities $ 1,288 $ 796 $ 492 Debt securities 895 277 618 Other securities 239 186 53 Total investment securities in the Funds $ 2,422 $ 1,259 $ 1,163 At December 31, 2022: Equity securities $ 1,095 $ 690 $ 405 Debt securities 838 267 571 Other securities 210 168 42 Total investment securities in the Funds () $ 2,143 $ 1,125 $ 1,018 () For Southern Company and Georgia Power, these amounts include investment securities pledged to creditors and collateral received and excludes payables related to a securities lending program Georgia Power's Funds previously participated in through the managers of the Funds. Under this program, Georgia Power's Funds' investment securities were loaned to institutional investors for a fee. Securities loaned were fully collateralized by cash, letters of credit, and/or securities issued or guaranteed by the U.S. government or its agencies or instrumentalities. At December 31, 2022, approximately $35 million of the fair market value of Georgia Power's Funds' securities were on loan and pledged to creditors under the Funds' managers' securities lending program. At December 31, 2022, the fair value of the collateral received was approximately $36 million and could only be sold by the borrower upon the return of the loaned securities. The collateral received was treated as a non-cash item in the statements of cash flows. These amounts exclude receivables related to investment income and pending investment sales and payables related to pending investment purchases. The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2023, 2022, and 2021 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2023 $ 281 $ 157 $ 124 2022 (360) (171) (189) 2021 274 200 74 Unrealized gains (losses) At December 31, 2023 $ 241 $ 119 $ 122 At December 31, 2022 (391) (204) (187) At December 31, 2021 (27) (30) 3 The investment securities held in the Funds continue to be managed with a long-term focus. Accordingly, all purchases and sales within the Funds are presented separately in the statements of cash flows as investing cash flows, consistent with the nature of the securities and purpose for which the securities were acquired. For Alabama Power, approximately $13 million and $14 million at December 31, 2023 and 2022, respectively, previously recorded in internal reserves is being transferred into the Funds through 2040 as approved by the Alabama PSC. The NRC's minimum external funding requirements are based on a generic estimate of the cost to decommission only the radioactive portions of a nuclear unit based on the size and type of reactor. Alabama Power and Georgia Power have filed plans with the NRC designed to ensure that, over time, the deposits and earnings of the Funds will provide the minimum funding amounts prescribed by the NRC. At December 31, 2023 and 2022, the accumulated provisions for the external decommissioning trust funds were as follows: 2023 2022 (in millions) Alabama Power Plant Farley $ 1,259 $ 1,125 Georgia Power Plant Hatch $ 705 $ 628 Plant Vogtle Units 1 and 2 434 382 Plant Vogtle Units 3 and 4 24 8 Total $ 1,163 $ 1,018 Site study cost is the estimate to decommission a specific facility as of the site study year. The decommissioning cost estimates are based on removal of the plant from service and prompt dismantlement. The actual decommissioning costs may vary from these estimates because of changes in the assumed date of decommissioning, changes in NRC requirements, or changes in the assumptions used in making these estimates. The estimated costs of decommissioning at December 31, 2023 based on the most current studies were as follows: Alabama Power Georgia Power Plant Plant Hatch () Plant Vogtle Units 1 and 2 () Plant Vogtle Unit 3 () Most current study year 2023 2021 2021 2020 Decommissioning periods: Beginning year 2037 2034 2047 2063 Completion year 2087 2075 2079 2074 (in millions) Site study costs: Radiated structures $ 1,402 $ 771 $ 628 $ 284 Spent fuel management 513 186 170 30 Non-radiated structures 133 61 85 33 Total site study costs $ 2,048 $ 1,018 $ 883 $ 347 () Based on Georgia Power's ownership interests. For ratemaking purposes, Alabama Power's decommissioning costs are based on the site study and Georgia Power's decommissioning costs are based on the NRC generic estimate to decommission the radioactive portion of the facilities and the site study estimate for spent fuel management. Significant assumptions used to determine these costs for ratemaking were an estimated inflation rate of 4.5% for Plant Farley, 2.5% for Plants Hatch and Vogtle Units 1 and 2, and 2.4% for Plant Vogtle Unit 3 and an estimated trust earnings rate of 7.0% for Plant Farley, 4.5% for Plants Hatch and Vogtle Units 1 and 2, and 4.4% for Plant Vogtle Unit 3. Amounts previously contributed to the Funds for Plant Farley are currently projected to be adequate to meet the decommissioning obligations. Alabama Power's site-specific estimates of decommissioning costs for Plant Farley are updated every five years. The next site study for Alabama Power is expected to be completed in 2028. Projections of funds are reviewed with the Alabama PSC to ensure that, over time, the deposits and earnings of the Funds will provide adequate funding to cover the site-specific costs. If necessary, Alabama Power would seek the Alabama PSC's approval to address any changes in a manner consistent with NRC and other applicable requirements. Under the 2019 ARP, Georgia Power's annual decommissioning cost for ratemaking in 2021 and 2022 was a total of $4 million for Plant Hatch and Plant Vogtle Units 1 and 2. Effective January 1, 2023, as approved in the 2022 ARP, there is no annual decommissioning cost for ratemaking for Plant Hatch and Plant Vogtle Units 1 and 2. Any funding amount required by the NRC during the period covered by the 2022 ARP will be deferred to a regulatory asset and recovery is expected to be determined in Georgia Power's next base rate case. See Note 2 under "Georgia Power – Rate Plans – 2022 ARP" for additional information. Effective August 1, 2023, as approved under the Plant Vogtle Unit 3 and Common Facilities rate proceeding, Georgia Power's annual decommissioning cost for ratemaking is $8 million for Plant Vogtle Unit 3. See Note 2 under "Georgia Power – Nuclear Construction – Regulatory Matters" for additional information.

CONSOLIDATED ENTITIES AND EQUIT

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	12 Months Ended
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	Dec. 31, 2023
Equity Method Investments and Joint Ventures [Abstract]
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. If a venture is a VIE for which a Registrant is the primary beneficiary, the assets, liabilities, and results of operations of the entity are consolidated. The Registrants reassess the conclusion as to whether an entity is a VIE upon certain occurrences, which are deemed reconsideration events. For entities that are not determined to be VIEs, the Registrants evaluate whether they have control or significant influence over the investee to determine the appropriate consolidation and presentation. Generally, entities under the control of a Registrant are consolidated, and entities over which a Registrant can exert significant influence, but which a Registrant does not control, are accounted for under the equity method of accounting. Investments accounted for under the equity method are recorded within equity investments in unconsolidated subsidiaries in the balance sheets and, for Southern Company and Southern Company Gas, the equity income is recorded within earnings from equity method investments in the statements of income. See "SEGCO" and "Southern Company Gas" herein for additional information. Southern Company At December 31, 2023 and 2022, Southern Holdings had equity method investments totaling $126 million and $112 million, respectively, primarily related to investments in venture capital funds focused on energy and utility investments. Earnings from these investments were immaterial for all periods presented. SEGCO Alabama Power and Georgia Power own equally all of the outstanding capital stock of SEGCO, which owns electric generating units at Plant Gaston with a total rated capacity of 1,020 MWs, as well as associated transmission facilities. Retirement of SEGCO's generating units is currently expected to occur by December 31, 2028. However, Alabama Power, in conjunction with Georgia Power, is evaluating extending the operation of Plant Gaston Units 1 through 4 beyond the indicated retirement date. See Note 2 under "Georgia Power – Integrated Resource Plans" for additional information. Alabama Power and Georgia Power account for SEGCO using the equity method; Southern Company consolidates SEGCO. The capacity of these units is sold equally to Alabama Power and Georgia Power. Alabama Power and Georgia Power make payments sufficient to provide for the operating expenses, taxes, interest expense, and a ROE. The share of purchased power included in purchased power, affiliates in the statements of income totaled $112 million in 2023, $124 million in 2022, and $75 million in 2021 for Alabama Power and $115 million in 2023, $127 million in 2022, and $77 million in 2021 for Georgia Power. SEGCO paid dividends of $25 million in 2023, $14 million in 2022, and $14 million in 2021, one half of which were paid to each of Alabama Power and Georgia Power. In addition, Alabama Power and Georgia Power each recognize 50% of SEGCO's net income. Alabama Power, which owns and operates a generating unit adjacent to the SEGCO generating units, has a joint ownership agreement with SEGCO for the ownership of an associated gas pipeline. Alabama Power owns 14% of the pipeline with the remaining 86% owned by SEGCO. See Note 3 under "Guarantees" for additional information regarding guarantees of Alabama Power and Georgia Power related to SEGCO. Southern Power Variable Interest Entities Southern Power has certain subsidiaries that are determined to be VIEs. Southern Power is considered the primary beneficiary of these VIEs because it controls the most significant activities of the VIEs, including operating and maintaining the respective assets, and has the obligation to absorb expected losses of these VIEs to the extent of its equity interests. SP Solar and SP Wind SP Solar is owned by Southern Power and a limited partner. A wholly-owned subsidiary of Southern Power is the general partner and holds a 1% ownership interest, and another wholly-owned subsidiary of Southern Power owns a 66% ownership interest. The limited partner holds the remaining 33% noncontrolling interest. SP Solar qualifies as a VIE since the arrangement is structured as a limited partnership and the 33% limited partner does not have substantive kick-out rights against the general partner. At December 31, 2023 and 2022, SP Solar had total assets of $5.6 billion and $5.9 billion, respectively, total liabilities of $0.4 billion, and noncontrolling interests of $1.0 billion and $1.1 billion, respectively. Cash distributions from SP Solar are allocated 67% to Southern Power and 33% to the limited partner in accordance with their partnership interest percentage. Under the terms of the limited partnership agreement, distributions without limited partner consent are limited to available cash and SP Solar is obligated to distribute all such available cash to its partners each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. SP Wind is owned by Southern Power and three financial investors. A wholly-owned subsidiary of Southern Power owns 100% of the Class B membership interests and the three financial investors own 100% of the Class A membership interests. SP Wind qualifies as a VIE since the structure of the arrangement is similar to a limited partnership and the Class A members do not have substantive kick-out rights against Southern Power. At December 31, 2023 and 2022, SP Wind had total assets of $2.1 billion and $2.2 billion, respectively, total liabilities of $187 million and $169 million, respectively, and noncontrolling interests of $38 million and $39 million, respectively. Under the terms of the limited liability agreement, distributions without Class A member consent are limited to available cash and SP Wind is obligated to distribute all such available cash to its members each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. Cash distributions from SP Wind are generally allocated 60% to Southern Power and 40% to the three financial investors in accordance with the limited liability agreement. Southern Power consolidates both SP Solar and SP Wind, as the primary beneficiary, since it controls the most significant activities of each entity, including operating and maintaining their assets. Certain transfers and sales of the assets in the VIEs are subject to partner consent and the liabilities are non-recourse to the general credit of Southern Power. Liabilities consist of customary working capital items and do not include any long-term debt. Other Variable Interest Entities Southern Power has other consolidated VIEs that relate to certain subsidiaries that have either sold noncontrolling interests to tax equity investors or acquired less than a 100% interest from facility developers. These entities are considered VIEs because the arrangements are structured similar to a limited partnership and the noncontrolling members do not have substantive kick-out rights. At December 31, 2023 and 2022, the other VIEs had total assets of $1.7 billion and $1.8 billion, respectively, total liabilities of $0.2 billion, and noncontrolling interests of $0.8 billion. Under the terms of the partnership agreements, distributions of all available cash are required each month or quarter and additional distributions require partner consent. Equity Method Investments During 2023 and 2022, Southern Power sold its remaining equity method investments in wind projects and received proceeds totaling $50 million and $38 million, respectively. Earnings (loss) from these investments, including the gains associated with the sales, were immaterial for all periods presented. Southern Company Gas Equity Method Investments The carrying amounts of Southern Company Gas' equity method investments at December 31, 2023 and 2022 and related earnings (loss) from those investments for the years ended December 31, 2023, 2022, and 2021 were as follows: Investment Balance December 31, 2023 December 31, 2022 (in millions) SNG $ 1,202 $ 1,243 Other 33 33 Total $ 1,235 $ 1,276 Earnings (Loss) from Equity Method Investments 2023 2022 2021 (in millions) SNG $ 139 $ 146 $ 127 PennEast Pipeline () — — (81) Other 1 2 4 Total $ 140 $ 148 $ 50 () For 2021, includes pre-tax impairment charges totaling $84 million. See "PennEast Pipeline Project" herein for additional information, including the September 2021 cancellation of the project. PennEast Pipeline Project In 2014, Southern Company Gas entered into a partnership in which it holds a 20% ownership interest in the PennEast Pipeline, an interstate pipeline company formed to develop and operate an approximate 118-mile natural gas pipeline between New Jersey and Pennsylvania. In 2019, an appellate court ruled that the PennEast Pipeline does not have federal eminent domain authority over lands in which a state has property rights interests. In June 2021, the U.S. Supreme Court ruled in favor of PennEast Pipeline following a review of the appellate court decision. Southern Company Gas assesses its equity method investments for impairment whenever events or changes in circumstances indicate that the investment may be impaired. Following the U.S. Supreme Court ruling, during the second quarter 2021, Southern Company Gas management reassessed the project construction timing, including the anticipated timing for receipt of a FERC certificate and all remaining state and local permits, as well as potential challenges thereto, and performed an impairment analysis. The outcome of the analysis resulted in a pre-tax impairment charge of $82 million ($58 million after tax). In September 2021, PennEast Pipeline announced that further development of the project was no longer supported, and, as a result, all further development of the project ceased. During the third quarter 2021, Southern Company Gas recorded an additional pre-tax charge of $2 million ($2 million after tax) related to its share of the project level impairment, as well as $7 million of additional tax expense, resulting in total pre-tax charges of $84 million ($67 million after tax) during 2021 related to the project.

FINANCING

FINANCING	12 Months Ended
FINANCING	Dec. 31, 2023
Debt Disclosure [Abstract]
FINANCING	FINANCING Long-term Debt Details of long-term debt at December 31, 2023 and 2022 are provided in the following table: At December 31, 2023 Balance Outstanding at Maturity Weighted Average 2023 2022 (in millions) Southern Company Senior notes (a) 2024-2073 4.16% $ 40,235 $ 35,683 Junior subordinated notes 2024-2081 4.33% 8,333 8,836 FFB loans (b) 2024-2044 2.88% 4,788 4,874 Revenue bonds (c) 2024-2063 3.77% 3,400 2,844 First mortgage bonds (d) 2025-2063 3.64% 2,500 2,275 Medium-term notes 2026-2027 7.03% 84 84 Other long-term debt 2024-2045 5.44% 234 167 Finance lease obligations (e) 298 314 Unamortized fair value adjustment 302 330 Unamortized debt premium (discount), net (198) (193) Unamortized debt issuance expenses (290) (273) Total long-term debt 59,686 54,941 Less: Amount due within one year 2,476 4,285 Total long-term debt excluding amount due within one year $ 57,210 $ 50,656 Alabama Power Senior notes 2025-2073 3.95% $ 9,875 $ 9,675 Revenue bonds (c) 2024-2063 3.94% 1,321 995 Other long-term debt 2026-2030 7.04% 75 45 Finance lease obligations (e) 5 5 Unamortized debt premium (discount), net (20) (18) Unamortized debt issuance expenses (73) (72) Total long-term debt 11,183 10,630 Less: Amount due within one year 223 301 Total long-term debt excluding amount due within one year $ 10,960 $ 10,329 Georgia Power Senior notes 2024-2052 4.34% $ 9,575 $ 7,925 Junior subordinated notes 2077 5.00% 270 270 FFB loans (b) 2024-2044 2.88% 4,788 4,874 Revenue bonds (c) 2025-2062 3.64% 1,968 1,738 Finance lease obligations (e) 240 238 Unamortized debt premium (discount), net (19) (18) Unamortized debt issuance expenses (122) (117) Total long-term debt 16,700 14,910 Less: Amount due within one year 502 901 Total long-term debt excluding amount due within one year $ 16,198 $ 14,009 At December 31, 2023 Balance Outstanding at Maturity Weighted Average 2023 2022 (in millions) Mississippi Power Senior notes 2024-2051 4.27% $ 1,525 $ 1,425 Revenue bonds (c) 2025-2052 4.08% 111 111 Finance lease obligations (e) 16 17 Unamortized debt premium (discount), net 1 2 Unamortized debt issuance expenses (9) (10) Total long-term debt 1,644 1,545 Less: Amount due within one year 201 1 Total long-term debt excluding amount due within one year $ 1,443 $ 1,544 Southern Power Senior notes (a) 2025-2046 4.05% $ 2,728 $ 2,998 Unamortized debt premium (discount), net (4) (5) Unamortized debt issuance expenses (13) (14) Total long-term debt 2,711 2,979 Less: Amount due within one year — 290 Total long-term debt excluding amount due within one year $ 2,711 $ 2,689 Southern Company Gas Senior notes 2025-2051 4.36% $ 4,930 $ 4,769 First mortgage bonds (d) 2025-2063 3.64% 2,500 2,275 Medium-term notes 2026-2027 7.03% 84 84 Other long-term debt 2024-2045 3.81% 59 22 Unamortized fair value adjustment 302 330 Unamortized debt premium (discount), net (8) (8) Unamortized debt issuance expenses (34) (30) Total long-term debt 7,833 7,442 Less: Amount due within one year — 400 Total long-term debt excluding amount due within one year $ 7,833 $ 7,042 (a) Includes a fair value gain (loss) of $(12) million and $(31) million at December 31, 2023 and 2022, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes. (b) Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred. (d) Secured by substantially all of Nicor Gas' properties. (e) Secured by the underlying lease ROU asset. See Note 9 for additional information. Maturities of long-term debt for the next five years are as follows: Southern Company (a) Alabama Power (b) Georgia Power (c) Mississippi Power Southern Power (d) Southern Company (in millions) 2024 $ 2,480 $ 223 $ 503 $ 201 $ — $ — 2025 4,124 251 849 12 500 300 2026 3,791 46 448 66 964 530 2027 2,075 551 512 10 — 154 2028 2,612 107 864 357 — 150 (a) See notes (b) and (c) below. (b) Alabama Power's 2024 maturities include $200 million aggregate principal amount of Series 2023A Floating Rate Senior Notes due May 15, 2073 that are repayable at the option of the holders at certain dates beginning in 2024. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Alabama Power at December 31, 2023. (c) Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. (d) Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar denominated hedge settlement amount. DOE Loan Guarantee Borrowings Pursuant to the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 (Title XVII Loan Guarantee Program), Georgia Power and the DOE entered into a loan guarantee agreement in 2014 and the Amended and Restated Loan Guarantee Agreement in 2019. Under the Amended and Restated Loan Guarantee Agreement, the DOE agreed to guarantee the obligations of Georgia Power under the FFB Credit Facilities. Under the FFB Credit Facilities, Georgia Power was authorized to make term loan borrowings through the FFB in an amount up to approximately $5.130 billion, provided that total aggregate borrowings under the FFB Credit Facilities could not exceed 70% of (i) Eligible Project Costs minus (ii) approximately $1.492 billion (reflecting the amounts received by Georgia Power under the Guarantee Settlement Agreement less the related customer refunds). In 2021, Georgia Power made the final borrowings under the FFB Credit Facilities and no further borrowings are permitted. During 2023, Georgia Power made principal amortization payments of $86 million under the FFB Credit Facilities. At December 31, 2023 and 2022, Georgia Power had $4.8 billion and $4.9 billion of borrowings outstanding under the FFB Credit Facilities, respectively. All borrowings under the FFB Credit Facilities are full recourse to Georgia Power, and Georgia Power is obligated to reimburse the DOE for any payments the DOE is required to make to the FFB under its guarantee. Georgia Power's reimbursement obligations to the DOE are full recourse and secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. There are no restrictions on Georgia Power's ability to grant liens on other property. The final maturity date for each advance under the FFB Credit Facilities is February 20, 2044. Interest is payable quarterly and principal payments began in 2020. Each borrowing under the FFB Credit Facilities bears interest at a fixed rate equal to the applicable U.S. Treasury rate at the time of the borrowing plus a spread equal to 0.375%. Under the Amended and Restated Loan Guarantee Agreement, Georgia Power is subject to customary borrower affirmative and negative covenants and events of default. In addition, Georgia Power is subject to project-related reporting requirements and other project-specific covenants and events of default. In the event certain mandatory prepayment events occur, Georgia Power will be required to prepay the outstanding principal amount of all borrowings under the FFB Credit Facilities over a period of five years (with level principal amortization). Among other things, these mandatory prepayment events include (i) the termination of the Vogtle Services Agreement or rejection of the Vogtle Services Agreement in any Westinghouse bankruptcy if Georgia Power does not maintain access to intellectual property rights under the related intellectual property licenses; (ii) termination of the Bechtel Agreement by Bechtel or in connection with a cancellation of Plant Vogtle Units 3 and 4, unless the Vogtle Owners enter into a replacement agreement; (iii) cancellation of Plant Vogtle Unit 4 by the Georgia PSC or by Georgia Power; (iv) failure of the holders of 90% of the ownership interests in Plant Vogtle Units 3 and 4 to vote to continue construction following certain schedule extensions; (v) cost disallowances by the Georgia PSC that could have a material adverse effect on completion of Plant Vogtle Unit 4 or Georgia Power's ability to repay the outstanding borrowings under the FFB Credit Facilities; or (vi) loss of or failure to receive necessary regulatory approvals. Under certain circumstances, insurance proceeds and any proceeds from an event of taking must be applied to immediately prepay outstanding borrowings under the FFB Credit Facilities. Georgia Power also may voluntarily prepay outstanding borrowings under the FFB Credit Facilities. Under the FFB Credit Facilities, any prepayment (whether mandatory or optional) will be made with a make-whole premium or discount, as applicable. In connection with any cancellation of Plant Vogtle Unit 4, the DOE may elect to continue construction of Plant Vogtle Unit 4. In such an event, the DOE will have the right to assume Georgia Power's rights and obligations under the principal agreements relating to Plant Vogtle Units 3 and 4 and to acquire all or a portion of Georgia Power's ownership interest in Plant Vogtle Units 3 and 4. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. Secured Debt Each of Southern Company's subsidiaries is organized as a legal entity, separate and apart from Southern Company and its other subsidiaries. There are no agreements or other arrangements among the Southern Company system companies under which the assets of one company have been pledged or otherwise made available to satisfy obligations of Southern Company or any of its other subsidiaries. As discussed under "Long-term Debt" herein, the Registrants had secured debt outstanding at December 31, 2023 and 2022. Each Registrant's senior notes, junior subordinated notes, revenue bond obligations, bank term loans, credit facility borrowings, and notes payable are effectively subordinated to all secured debt of each respective Registrant. Equity Units In May 2022, Southern Company remarketed $862.5 million aggregate principal amount of its Series 2019A Remarketable Junior Subordinated Notes due August 1, 2024 (2019A RSNs) and $862.5 million aggregate principal amount of its Series 2019B Remarketable Junior Subordinated Notes due August 1, 2027 (2019B RSNs), pursuant to the terms of its 2019 Series A Equity Units (Equity Units). In connection with the remarketing, the interest rates on the 2019A RSNs and the 2019B RSNs were reset to 4.475% and 5.113%, respectively, payable on a semi-annual basis. In August 2022, the proceeds were ultimately used to settle the purchase contracts entered into as part of the Equity Units and Southern Company issued approximately 25.2 million shares of common stock and received proceeds of $1.725 billion. At December 31, 2023 and 2022, the 2019A RSNs and the 2019B RSNs are included on Southern Company's consolidated balance sheets in long-term debt or, as applicable, securities due within one year. Convertible Senior Notes In February 2023, Southern Company issued $1.5 billion aggregate principal amount of Series 2023A 3.875% Convertible Senior Notes due December 15, 2025 (Series 2023A Convertible Senior Notes). In March 2023, Southern Company issued an additional $225 million aggregate principal amount of the Series 2023A Convertible Senior Notes upon the exercise by the initial purchasers of their over-allotment option. Interest on the Series 2023A Convertible Senior Notes is payable semiannually, which began on June 15, 2023. The Series 2023A Convertible Senior Notes will mature on December 15, 2025, unless earlier converted or repurchased, but are not redeemable at the option of Southern Company. The Series 2023A Convertible Senior Notes are direct, unsecured, and unsubordinated obligations of Southern Company, ranking equally with all of Southern Company's other unsecured and unsubordinated indebtedness from time to time outstanding, and are effectively subordinated to all secured indebtedness of Southern Company. Holders may convert their Series 2023A Convertible Senior Notes at their option prior to the close of business on the business day preceding September 15, 2025, but only under the following circumstances: • during any calendar quarter (and only during such calendar quarter), if the last reported sale price of Southern Company's common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on, and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day as determined by Southern Company; • during the five business day period after any 10 consecutive trading day period (Measurement Period) in which the trading price per $1,000 principal amount of Series 2023A Convertible Senior Notes for each trading day of the Measurement Period was less than 98% of the product of the last reported sale price of the common stock and the conversion rate on each such trading day; or • upon the occurrence of certain corporate events specified in the indenture governing the Series 2023A Convertible Senior Notes. On or after September 15, 2025, a holder may convert all or any portion of its Series 2023A Convertible Senior Notes at any time prior to the close of business on the second scheduled trading day immediately preceding the maturity date regardless of the foregoing conditions. Southern Company will settle conversions of the Series 2023A Convertible Senior Notes by paying cash up to the aggregate principal amount of the Series 2023A Convertible Senior Notes to be converted and paying or delivering, as the case may be, cash, shares of common stock or a combination of cash and shares of common stock, at Southern Company's election, in respect of the remainder, if any, of Southern Company's conversion obligation in excess of the aggregate principal amount of the Series 2023A Convertible Senior Notes being converted. The Series 2023A Convertible Senior Notes are initially convertible at a rate of 11.8818 shares of common stock per $1,000 principal amount converted, which is approximately equal to $84.16 per share of common stock. The conversion rate will be subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, upon the occurrence of a make-whole fundamental change (as defined in the indenture governing the Series 2023A Convertible Senior Notes), Southern Company will, in certain circumstances, increase the conversion rate by a number of additional shares of common stock for conversions in connection with the make-whole fundamental change. Upon the occurrence of a fundamental change (as defined in the indenture governing the Series 2023A Convertible Senior Notes), holders of the Series 2023A Convertible Senior Notes may require Southern Company to purchase all or a portion of their Series 2023A Convertible Senior Notes, in principal amounts equal to $1,000 or an integral multiple thereof, for cash at a price equal to 100% of the principal amount of the Series 2023A Convertible Senior Notes to be purchased plus any accrued and unpaid interest. Bank Credit Arrangements At December 31, 2023, committed credit arrangements with banks were as follows: Expires Company 2024 2025 2026 2028 Total Unused Expires within One Year (in millions) Southern Company parent (a) $ 150 $ — $ — $ 1,850 $ 2,000 $ 1,998 $ 150 Alabama Power — — 650 700 1,350 1,350 — Georgia Power — — — 1,750 1,750 1,726 — Mississippi Power — 125 150 — 275 275 — Southern Power (a)(b) — — — 600 600 589 — Southern Company Gas (c) 100 — — 1,500 1,600 1,598 100 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 125 $ 800 $ 6,400 $ 7,605 $ 7,566 $ 280 (a) Arrangement expiring in 2028 represents a $2.45 billion combined arrangement for Southern Company and Southern Power as borrowers. Pursuant to the combined facility, the allocations between Southern Company and Southern Power may be adjusted. (b) Does not include Southern Power Company's $75 million and $100 million continuing letter of credit facilities for standby letters of credit, expiring in 2025 and 2026, respectively , of which $8 million and $7 million, respectively, was unused at December 31, 2023. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities. (c) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2028. Southern Company Gas' committed credit arrangement expiring in 2028 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2028, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $100 million credit arrangement expiring in 2024. See "Structural Considerations" herein for additional information. The bank credit arrangements require payment of commitment fees based on the unused portion of the commitments. Commitment fees average less than 1 / 4 of 1% for the Registrants and Nicor Gas. Subject to applicable market conditions, Southern Company and its subsidiaries expect to renew or replace their bank credit arrangements as needed, prior to expiration. In connection therewith, Southern Company and its subsidiaries may extend the maturity dates and/or increase or decrease the lending commitments thereunder. These bank credit arrangements, as well as the term loan arrangements of the Registrants, Nicor Gas, and SEGCO, contain covenants that limit debt levels and contain cross-acceleration provisions to other indebtedness (including guarantee obligations) that are restricted only to the indebtedness of the individual company. The cross-acceleration provisions to other indebtedness would trigger an event of default if the applicable borrower defaulted on indebtedness, the payment of which was then accelerated. Southern Company's, certain of Mississippi Power's, Southern Company Gas', and Nicor Gas' credit arrangements contain covenants that limit debt levels to 70% of total capitalization, as defined in the agreements, and the other subsidiaries' bank credit arrangements contain covenants that limit debt levels to 65% of total capitalization, as defined in the agreements. For purposes of these definitions, debt excludes junior subordinated notes and, in certain arrangements, other hybrid securities. Additionally, for Southern Company and Southern Power, for purposes of these definitions, debt excludes any project debt incurred by certain subsidiaries of Southern Power to the extent such debt is non-recourse to Southern Power and capitalization excludes the capital stock or other equity attributable to such subsidiaries. At December 31, 2023, the Registrants, Nicor Gas, and SEGCO were in compliance with all such covenants. None of the bank credit arrangements contain material adverse change clauses at the time of borrowings. A portion of the unused credit with banks is allocated to provide liquidity support to certain revenue bonds of the traditional electric operating companies and the commercial paper programs of the Registrants, Nicor Gas, and SEGCO. At December 31, 2023, outstanding variable rate demand revenue bonds of the traditional electric operating companies with allocated liquidity support totaled approximately $1.7 billion (comprised of approximately $818 million at Alabama Power, $819 million at Georgia Power, and $69 million at Mississippi Power). In addition, at December 31, 2023, Georgia Power had approximately $325 million of fixed rate revenue bonds outstanding that are required to be remarketed within the next 12 months. The variable rate demand revenue bonds and fixed rate revenue bonds required to be remarketed within the next 12 months are classified as long-term debt on the balance sheets as a result of available long-term committed credit. At both December 31, 2023 and 2022, Southern Power had $106 million of cash collateral posted related to PPA requirements, which is included in other deferred charges and assets on Southern Power's consolidated balance sheets. Notes Payable The Registrants, Nicor Gas, and SEGCO make short-term borrowings primarily through commercial paper programs that have the liquidity support of the committed bank credit arrangements described above under "Bank Credit Arrangements." Southern Power's subsidiaries are not parties or obligors to its commercial paper program. Southern Company Gas maintains commercial paper programs at Southern Company Gas Capital and at Nicor Gas. Nicor Gas' commercial paper program supports working capital needs at Nicor Gas as Nicor Gas is not permitted to make money pool loans to affiliates. All of Southern Company Gas' other subsidiaries benefit from Southern Company Gas Capital's commercial paper program. See "Structural Considerations" herein for additional information. In addition, Southern Company and certain of its subsidiaries have entered into various bank term loan agreements. Unless otherwise stated, the proceeds of these loans were used to repay existing indebtedness and for general corporate purposes, including working capital and, for the subsidiaries, their continuous construction programs. Commercial paper and short-term bank term loans are included in notes payable in the balance sheets. Details of short-term borrowings for the applicable Registrants were as follows: Notes Payable at December 31, 2023 Notes Payable at December 31, 2022 Amount Weighted Average Amount Weighted Average (in millions) (in millions) Southern Company Commercial paper $ 1,794 5.6 % $ 809 4.7 % Short-term bank debt 520 6.4 % 1,800 5.0 % Total $ 2,314 5.7 % $ 2,609 4.9 % Alabama Power Commercial paper $ 40 5.5 % $ — — % Georgia Power Commercial paper $ 809 5.6 % $ — — % Short-term bank debt 520 6.4 % 1,600 5.0 % Total $ 1,329 5.9 % $ 1,600 5.0 % Southern Power Commercial paper $ 138 5.5 % $ 225 4.7 % Southern Company Gas Commercial paper: Southern Company Gas Capital $ 23 5.5 % $ 285 4.8 % Nicor Gas 392 5.5 % 283 4.6 % Short-term bank debt: Nicor Gas — — % 200 4.9 % Total $ 415 5.5 % $ 768 4.7 % See "Bank Credit Arrangements" herein for information on bank term loan covenants that limit debt levels and cross-acceleration or cross-default provisions. Outstanding Classes of Capital Stock Southern Company Common Stock Stock Issued During 2023, Southern Company issued approximately 2.1 million shares of common stock primarily through equity compensation plans and received proceeds of approximately $36 million. Shares Reserved At December 31, 2023, a total of 131 million shares were reserved for issuance pursuant to the Southern Investment Plan, employee savings plans, the Equity and Incentive Compensation Plan (which includes stock options and performance share units as discussed in Note 12), an at-the-market program, and the Series 2023A Convertible Senior Notes (as discussed under "Convertible Senior Notes" herein). Of the shares reserved, 26.9 million shares are available for awards under the Equity and Incentive Compensation Plan at December 31, 2023. Diluted Earnings Per Share For Southern Company, the only difference in computing basic and diluted earnings per share (EPS) is attributable to awards outstanding under stock-based compensation plans and the Series 2023A Convertible Senior Notes. EPS dilution resulting from stock-based compensation plans is determined using the treasury stock method and EPS dilution resulting from the Series 2023A Convertible Senior Notes is determined using the net share settlement method. See Note 12 and "Convertible Senior Notes" herein for additional information. Shares used to compute diluted EPS were as follows: Average Common Stock Shares 2023 2022 2021 (in millions) As reported shares 1,092 1,075 1,061 Effect of stock-based compensation 6 6 7 Diluted shares 1,098 1,081 1,068 For 2023, there were no anti-dilutive shares. For 2022 and 2021, an immaterial number of stock-based compensation awards was excluded from the diluted EPS calculation because the awards were anti-dilutive. For all periods presented, there was no dilution resulting from the Series 2023A Convertible Senior Notes. Preferred Stock of Subsidiaries As discussed further under "Alabama Power" herein, during 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock. Alabama Power Alabama Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding at December 31, 2023. During 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock at the redemption prices per share provided in the table below, plus accrued and unpaid dividends to the redemption date. Preferred Stock Redeemed During 2022 Par Value/Stated Capital Per Share Shares Redemption 4.92% Preferred Stock $100 80,000 $103.23 4.72% Preferred Stock $100 50,000 $102.18 4.64% Preferred Stock $100 60,000 $103.14 4.60% Preferred Stock $100 100,000 $104.20 4.52% Preferred Stock $100 50,000 $102.93 4.20% Preferred Stock $100 135,115 $105.00 5.00% Class A Preferred Stock $25 10,000,000 $25.00 Georgia Power Georgia Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding. Mississippi Power Dividend Restrictions The income of Southern Company is derived primarily from equity in earnings of its subsidiaries. At December 31, 2023, consolidated retained earnings included $5.5 billion of undistributed retained earnings of the subsidiaries. The traditional electric operating companies and Southern Power can only pay dividends to Southern Company out of retained earnings or paid-in-capital. See Note 7 under "Southern Power" for information regarding the distribution requirements for certain Southern Power subsidiaries. By regulation, Nicor Gas is restricted, up to its retained earnings balance, in the amount it can dividend or loan to affiliates and is not permitted to make money pool loans to affiliates. At December 31, 2023, the amount of Southern Company Gas' subsidiary retained earnings available for dividend payment totaled $1.7 billion. Structural Considerations Since Southern Company and Southern Company Gas are holding companies, the right of Southern Company and Southern Company Gas and, hence, the right of creditors of Southern Company or Southern Company Gas to participate in any distribution of the assets of any respective subsidiary of Southern Company or Southern Company Gas, whether upon liquidation, reorganization or otherwise, is subject to prior claims of creditors and preferred stockholders of such subsidiary. Southern Company Gas' 100%-owned subsidiary, Southern Company Gas Capital, was established to provide for certain of Southern Company Gas' ongoing financing needs through a commercial paper program, the issuance of various debt, hybrid securities, and other financing arrangements. Southern Company Gas fully and unconditionally guarantees all debt issued by Southern Company Gas Capital. Nicor Gas is not permitted by regulation to make loans to affiliates or utilize Southern Company Gas Capital for its financing needs. Southern Power Company's senior notes, bank term loan, commercial paper, and bank credit arrangement are unsecured senior indebtedness, which rank equally with all other unsecured and unsubordinated debt of Southern Power Compan y. Southern Power's subsidiaries are not issuers, borrowers, or obligors, as applicable, under any of these unsecured senior debt arrangements, which are effectively subordinated to any future secured debt of Southern Power Company and any potential claims of creditors of Southern Power's subsidiaries.

LEASES

LEASES	12 Months Ended
LEASES	Dec. 31, 2023
Leases [Abstract]
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Electric generating units () $ 670 $ 58 $ 1,028 $ — $ — $ — Real estate/land 871 4 54 2 546 28 Communication towers 123 1 4 — — 23 Railcars 64 32 27 5 — — Other 60 3 2 18 — — Total $ 1,788 $ 98 $ 1,115 $ 25 $ 546 $ 51 At December 31, 2022 Electric generating units () $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 () Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 27 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 17 years. Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2023 and 2022. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Operating Leases Operating lease ROU assets, net $ 1,432 $ 87 $ 884 $ 9 $ 488 $ 47 Operating lease obligations - current $ 183 $ 12 $ 135 $ 3 $ 29 $ 11 Operating lease obligations - non-current 1,307 81 740 6 517 40 Total operating lease obligations () $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance Leases Finance lease ROU assets, net $ 272 $ 5 $ 203 $ 15 $ — $ — Finance lease obligations - current $ 11 $ 2 $ 18 $ 1 $ — $ — Finance lease obligations - non-current 287 3 222 15 — — Total finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations () $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — () Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $566 million, $58 million, and $813 million, respectively, at December 31, 2023 and $652 million, $59 million, and $952 million, respectively, at December 31, 2022. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2023, 2022, and 2021, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease cost Operating lease cost () $ 252 $ 16 $ 192 $ 5 $ 34 $ 12 Finance lease cost: Amortization of ROU assets 24 2 19 1 — — Interest on lease obligations 14 — 17 — — — Total finance lease cost 38 2 36 1 — — Short-term lease costs 40 16 16 — — — Variable lease cost 47 — 74 — 4 — Sublease income — — — — — — Total lease cost $ 377 $ 34 $ 318 $ 6 $ 38 $ 12 2022 Lease cost Operating lease cost () $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost () $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 () Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $112 million, $4 million, and $174 million, respectively, in 2023, $162 million, $48 million, and $180 million, respectively, in 2022, and $165 million, $47 million, and $184 million, respectively, in 2021. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $42 million, $45 million, and $41 million in 2023, 2022, and 2021, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $21 million, and $20 million was included in purchased power, affiliates in 2023, 2022, and 2021, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 253 $ 17 $ 199 $ 5 $ 33 $ 12 Operating cash flows from finance leases 15 — 22 — — — Financing cash flows from finance leases 18 2 16 1 — — ROU assets obtained under operating leases 100 30 26 1 7 7 ROU assets obtained under finance leases 3 3 18 — — — 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2023 Weighted-average remaining lease term in years: Operating leases 17.2 11.1 7.5 4.6 33.1 7.0 Finance leases 16.7 4.3 10.6 11.9 N/A N/A Weighted-average discount rate: Operating leases 4.68 % 5.02 % 4.58 % 3.67 % 4.89 % 3.80 % Finance leases 4.85 % 3.93 % 5.95 % 2.74 % N/A N/A At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 15 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 23 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 18 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 19 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 10 years. Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book value of $39 million was transferred from CWIP to lease receivables. The transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2023 Southern Company Mississippi Power Southern (in millions) 2024 $ 38 $ 23 $ 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 2028 34 19 15 Thereafter 330 145 185 Total undiscounted cash flows $ 510 $ 250 $ 260 Net investment in sales-type lease () 311 148 163 Difference between undiscounted cash flows and discounted cash flows $ 199 $ 102 $ 97 () For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2023 and 2022, respectively) and net investment in sales-type leases ($148 million and $154 million at December 31, 2023 and 2022, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2023 Southern Alabama Southern Southern Company Gas (in millions) 2024 $ 116 $ 7 $ 90 $ 35 2025 107 5 75 29 2026 108 5 73 29 2027 105 4 75 28 2028 104 3 76 28 Thereafter 706 26 91 354 Total $ 1,246 $ 50 $ 480 $ 503 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2023, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of eight years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease. The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 (in millions) Pretax leveraged lease income $ 17 Income tax expense (5) Net leveraged lease income $ 12 In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed on July 14, 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Electric generating units () $ 670 $ 58 $ 1,028 $ — $ — $ — Real estate/land 871 4 54 2 546 28 Communication towers 123 1 4 — — 23 Railcars 64 32 27 5 — — Other 60 3 2 18 — — Total $ 1,788 $ 98 $ 1,115 $ 25 $ 546 $ 51 At December 31, 2022 Electric generating units () $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 () Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 27 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 17 years. Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2023 and 2022. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Operating Leases Operating lease ROU assets, net $ 1,432 $ 87 $ 884 $ 9 $ 488 $ 47 Operating lease obligations - current $ 183 $ 12 $ 135 $ 3 $ 29 $ 11 Operating lease obligations - non-current 1,307 81 740 6 517 40 Total operating lease obligations () $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance Leases Finance lease ROU assets, net $ 272 $ 5 $ 203 $ 15 $ — $ — Finance lease obligations - current $ 11 $ 2 $ 18 $ 1 $ — $ — Finance lease obligations - non-current 287 3 222 15 — — Total finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations () $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — () Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $566 million, $58 million, and $813 million, respectively, at December 31, 2023 and $652 million, $59 million, and $952 million, respectively, at December 31, 2022. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2023, 2022, and 2021, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease cost Operating lease cost () $ 252 $ 16 $ 192 $ 5 $ 34 $ 12 Finance lease cost: Amortization of ROU assets 24 2 19 1 — — Interest on lease obligations 14 — 17 — — — Total finance lease cost 38 2 36 1 — — Short-term lease costs 40 16 16 — — — Variable lease cost 47 — 74 — 4 — Sublease income — — — — — — Total lease cost $ 377 $ 34 $ 318 $ 6 $ 38 $ 12 2022 Lease cost Operating lease cost () $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost () $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 () Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $112 million, $4 million, and $174 million, respectively, in 2023, $162 million, $48 million, and $180 million, respectively, in 2022, and $165 million, $47 million, and $184 million, respectively, in 2021. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $42 million, $45 million, and $41 million in 2023, 2022, and 2021, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $21 million, and $20 million was included in purchased power, affiliates in 2023, 2022, and 2021, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 253 $ 17 $ 199 $ 5 $ 33 $ 12 Operating cash flows from finance leases 15 — 22 — — — Financing cash flows from finance leases 18 2 16 1 — — ROU assets obtained under operating leases 100 30 26 1 7 7 ROU assets obtained under finance leases 3 3 18 — — — 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2023 Weighted-average remaining lease term in years: Operating leases 17.2 11.1 7.5 4.6 33.1 7.0 Finance leases 16.7 4.3 10.6 11.9 N/A N/A Weighted-average discount rate: Operating leases 4.68 % 5.02 % 4.58 % 3.67 % 4.89 % 3.80 % Finance leases 4.85 % 3.93 % 5.95 % 2.74 % N/A N/A At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 15 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 23 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 18 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 19 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 10 years. Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book value of $39 million was transferred from CWIP to lease receivables. The transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2023 Southern Company Mississippi Power Southern (in millions) 2024 $ 38 $ 23 $ 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 2028 34 19 15 Thereafter 330 145 185 Total undiscounted cash flows $ 510 $ 250 $ 260 Net investment in sales-type lease () 311 148 163 Difference between undiscounted cash flows and discounted cash flows $ 199 $ 102 $ 97 () For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2023 and 2022, respectively) and net investment in sales-type leases ($148 million and $154 million at December 31, 2023 and 2022, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2023 Southern Alabama Southern Southern Company Gas (in millions) 2024 $ 116 $ 7 $ 90 $ 35 2025 107 5 75 29 2026 108 5 73 29 2027 105 4 75 28 2028 104 3 76 28 Thereafter 706 26 91 354 Total $ 1,246 $ 50 $ 480 $ 503 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2023, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of eight years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease. The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 (in millions) Pretax leveraged lease income $ 17 Income tax expense (5) Net leveraged lease income $ 12 In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed on July 14, 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Electric generating units () $ 670 $ 58 $ 1,028 $ — $ — $ — Real estate/land 871 4 54 2 546 28 Communication towers 123 1 4 — — 23 Railcars 64 32 27 5 — — Other 60 3 2 18 — — Total $ 1,788 $ 98 $ 1,115 $ 25 $ 546 $ 51 At December 31, 2022 Electric generating units () $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 () Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 27 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 17 years. Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2023 and 2022. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Operating Leases Operating lease ROU assets, net $ 1,432 $ 87 $ 884 $ 9 $ 488 $ 47 Operating lease obligations - current $ 183 $ 12 $ 135 $ 3 $ 29 $ 11 Operating lease obligations - non-current 1,307 81 740 6 517 40 Total operating lease obligations () $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance Leases Finance lease ROU assets, net $ 272 $ 5 $ 203 $ 15 $ — $ — Finance lease obligations - current $ 11 $ 2 $ 18 $ 1 $ — $ — Finance lease obligations - non-current 287 3 222 15 — — Total finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations () $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — () Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $566 million, $58 million, and $813 million, respectively, at December 31, 2023 and $652 million, $59 million, and $952 million, respectively, at December 31, 2022. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2023, 2022, and 2021, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease cost Operating lease cost () $ 252 $ 16 $ 192 $ 5 $ 34 $ 12 Finance lease cost: Amortization of ROU assets 24 2 19 1 — — Interest on lease obligations 14 — 17 — — — Total finance lease cost 38 2 36 1 — — Short-term lease costs 40 16 16 — — — Variable lease cost 47 — 74 — 4 — Sublease income — — — — — — Total lease cost $ 377 $ 34 $ 318 $ 6 $ 38 $ 12 2022 Lease cost Operating lease cost () $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost () $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 () Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $112 million, $4 million, and $174 million, respectively, in 2023, $162 million, $48 million, and $180 million, respectively, in 2022, and $165 million, $47 million, and $184 million, respectively, in 2021. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $42 million, $45 million, and $41 million in 2023, 2022, and 2021, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $21 million, and $20 million was included in purchased power, affiliates in 2023, 2022, and 2021, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 253 $ 17 $ 199 $ 5 $ 33 $ 12 Operating cash flows from finance leases 15 — 22 — — — Financing cash flows from finance leases 18 2 16 1 — — ROU assets obtained under operating leases 100 30 26 1 7 7 ROU assets obtained under finance leases 3 3 18 — — — 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2023 Weighted-average remaining lease term in years: Operating leases 17.2 11.1 7.5 4.6 33.1 7.0 Finance leases 16.7 4.3 10.6 11.9 N/A N/A Weighted-average discount rate: Operating leases 4.68 % 5.02 % 4.58 % 3.67 % 4.89 % 3.80 % Finance leases 4.85 % 3.93 % 5.95 % 2.74 % N/A N/A At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 15 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 23 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 18 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 19 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 10 years. Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book value of $39 million was transferred from CWIP to lease receivables. The transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2023 Southern Company Mississippi Power Southern (in millions) 2024 $ 38 $ 23 $ 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 2028 34 19 15 Thereafter 330 145 185 Total undiscounted cash flows $ 510 $ 250 $ 260 Net investment in sales-type lease () 311 148 163 Difference between undiscounted cash flows and discounted cash flows $ 199 $ 102 $ 97 () For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2023 and 2022, respectively) and net investment in sales-type leases ($148 million and $154 million at December 31, 2023 and 2022, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2023 Southern Alabama Southern Southern Company Gas (in millions) 2024 $ 116 $ 7 $ 90 $ 35 2025 107 5 75 29 2026 108 5 73 29 2027 105 4 75 28 2028 104 3 76 28 Thereafter 706 26 91 354 Total $ 1,246 $ 50 $ 480 $ 503 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2023, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of eight years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease. The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 (in millions) Pretax leveraged lease income $ 17 Income tax expense (5) Net leveraged lease income $ 12 In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed on July 14, 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Electric generating units () $ 670 $ 58 $ 1,028 $ — $ — $ — Real estate/land 871 4 54 2 546 28 Communication towers 123 1 4 — — 23 Railcars 64 32 27 5 — — Other 60 3 2 18 — — Total $ 1,788 $ 98 $ 1,115 $ 25 $ 546 $ 51 At December 31, 2022 Electric generating units () $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 () Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 27 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 17 years. Renewal options exist in many of the leases. The expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease unless it is considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2023 and 2022. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Operating Leases Operating lease ROU assets, net $ 1,432 $ 87 $ 884 $ 9 $ 488 $ 47 Operating lease obligations - current $ 183 $ 12 $ 135 $ 3 $ 29 $ 11 Operating lease obligations - non-current 1,307 81 740 6 517 40 Total operating lease obligations () $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance Leases Finance lease ROU assets, net $ 272 $ 5 $ 203 $ 15 $ — $ — Finance lease obligations - current $ 11 $ 2 $ 18 $ 1 $ — $ — Finance lease obligations - non-current 287 3 222 15 — — Total finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations () $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — () Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $566 million, $58 million, and $813 million, respectively, at December 31, 2023 and $652 million, $59 million, and $952 million, respectively, at December 31, 2022. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2023, 2022, and 2021, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease cost Operating lease cost () $ 252 $ 16 $ 192 $ 5 $ 34 $ 12 Finance lease cost: Amortization of ROU assets 24 2 19 1 — — Interest on lease obligations 14 — 17 — — — Total finance lease cost 38 2 36 1 — — Short-term lease costs 40 16 16 — — — Variable lease cost 47 — 74 — 4 — Sublease income — — — — — — Total lease cost $ 377 $ 34 $ 318 $ 6 $ 38 $ 12 2022 Lease cost Operating lease cost () $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost () $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 () Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $112 million, $4 million, and $174 million, respectively, in 2023, $162 million, $48 million, and $180 million, respectively, in 2022, and $165 million, $47 million, and $184 million, respectively, in 2021. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $42 million, $45 million, and $41 million in 2023, 2022, and 2021, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $21 million, and $20 million was included in purchased power, affiliates in 2023, 2022, and 2021, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 253 $ 17 $ 199 $ 5 $ 33 $ 12 Operating cash flows from finance leases 15 — 22 — — — Financing cash flows from finance leases 18 2 16 1 — — ROU assets obtained under operating leases 100 30 26 1 7 7 ROU assets obtained under finance leases 3 3 18 — — — 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2023 Weighted-average remaining lease term in years: Operating leases 17.2 11.1 7.5 4.6 33.1 7.0 Finance leases 16.7 4.3 10.6 11.9 N/A N/A Weighted-average discount rate: Operating leases 4.68 % 5.02 % 4.58 % 3.67 % 4.89 % 3.80 % Finance leases 4.85 % 3.93 % 5.95 % 2.74 % N/A N/A At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to 10 years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 15 years. For Southern Power, these arrangements consist of PPAs related to electric generating units accounted for as operating leases with remaining terms of up to 23 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 18 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 19 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 10 years. Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income related to PPAs for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book value of $39 million was transferred from CWIP to lease receivables. The transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2023 Southern Company Mississippi Power Southern (in millions) 2024 $ 38 $ 23 $ 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 2028 34 19 15 Thereafter 330 145 185 Total undiscounted cash flows $ 510 $ 250 $ 260 Net investment in sales-type lease () 311 148 163 Difference between undiscounted cash flows and discounted cash flows $ 199 $ 102 $ 97 () For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2023 and 2022, respectively) and net investment in sales-type leases ($148 million and $154 million at December 31, 2023 and 2022, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2023 Southern Alabama Southern Southern Company Gas (in millions) 2024 $ 116 $ 7 $ 90 $ 35 2025 107 5 75 29 2026 108 5 73 29 2027 105 4 75 28 2028 104 3 76 28 Thereafter 706 26 91 354 Total $ 1,246 $ 50 $ 480 $ 503 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2023, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of eight years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020 following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease. The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 (in millions) Pretax leveraged lease income $ 17 Income tax expense (5) Net leveraged lease income $ 12 In June 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. Subsequently, the lessee failed to make the semi-annual lease payment due in December 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease entered into forbearance agreements which suspended the related contractual rights of the parties while they continued restructuring negotiations, during which the termination date for the operating and maintenance agreement was delayed until July 31, 2023. The negotiations were completed on July 14, 2023, resulting in the Southern Holdings subsidiary agreeing to continue operating the plant for the lessee until the lessee's associated power off-take agreement ends in 2032, subject to certain terms and conditions. The restructuring had no material impact on Southern Company's financial statements. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to meet its obligations, including those associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.

INCOME TAXES

INCOME TAXES	12 Months Ended
INCOME TAXES	Dec. 31, 2023
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES Southern Company files a consolidated federal income tax return and the Registrants file various state income tax returns, some of which are combined or unitary. Under a joint consolidated income tax allocation agreement, each Southern Company subsidiary's current and deferred tax expense is computed on a stand-alone basis, and each subsidiary is allocated an amount of tax similar to that which would be paid if it filed a separate income tax return. In accordance with IRS regulations, each company is jointly and severally liable for the federal tax liability. Current and Deferred Income Taxes Details of income tax provisions are as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 54 $ 242 $ 205 $ 49 $ (320) $ 62 Deferred 299 (257) 195 (26) 334 68 Total federal 353 (15) 400 23 14 130 State — Current 41 82 37 1 (1) 24 Deferred 102 14 11 12 (1) 57 Total state 143 96 48 13 (2) 81 Total $ 496 $ 81 $ 448 $ 36 $ 12 $ 211 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 10 $ 54 $ 38 $ 42 $ (43) $ 122 Deferred 455 259 152 (16) 56 (3) Total federal 465 313 190 26 13 119 State — Current 27 14 (21) — 2 42 Deferred 303 96 201 11 5 19 Total state 330 110 180 11 7 61 Total $ 795 $ 423 $ 370 $ 37 $ 20 $ 180 2021 Southern Company Alabama Power Georgia Mississippi Southern Power Southern Company Gas (in millions) Federal — Current $ 50 $ 104 $ 311 $ 25 $ (340) $ 85 Deferred 36 172 (449) (15) 343 35 Total federal 86 276 (138) 10 3 120 State — Current (25) 23 71 — (16) (68) Deferred 206 73 (101) 11 — 223 Total state 181 96 (30) 11 (16) 155 Total $ 267 $ 372 $ (168) $ 21 $ (13) $ 275 Southern Company's and Southern Power's ITCs and PTCs generated in the current tax year and carried forward from prior tax years that cannot be utilized in the current tax year are reclassified from current to deferred taxes in federal income tax expense in the tables above. Southern Power's ITCs and PTCs reclassified in this manner include $5 million for 2023, $17 million for 2022, and $6 million for 2021. Southern Power received $332 million, $49 million, and $289 million of cash related to federal ITCs under renewable energy initiatives in 2023, 2022, and 2021, respectively. See "Deferred Tax Assets and Liabilities" herein for additional information. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. ITCs amortized in 2023, 2022, and 2021 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power: Southern Company Southern Power (in millions) 2023 $ 84 $ 58 2022 83 58 2021 84 58 When Southern Power recognizes tax credits, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs and other state credits, which are recognized in the period in which the credits are generated, reduced Georgia Power's income tax expense by $49 million in 2023, $53 million in 2022, and $66 million in 2021. Southern Power's federal and state PTCs, which are recognized in the period in which the credits are generated, reduced Southern Power's income tax expense by $26 million in 2023, $27 million in 2022, and $16 million in 2021. During the fourth quarter 2023, Southern Power executed an agreement to transfer certain PTCs generated in 2023 and received cash of $12 million. The discount recognized was booked through income tax expense and was immaterial. Pursuant to the Global Amendments to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Joint Owner Contracts"), Georgia Power paid $39 million to the other Vogtle Owners for advanced nuclear PTCs for Plant Vogtle Unit 3. The gain recognized in 2023 was booked through income tax benefit and was immaterial. Effective Tax Rate Southern Company's effective tax rate is typically lower than the statutory rate due to employee stock plans' dividend deduction, non-taxable AFUDC equity at the traditional electric operating companies, flowback of excess deferred income taxes at the regulated utilities, and federal income tax benefits from ITCs and PTCs primarily at Southern Power. In July 2021, Southern Company Gas affiliates completed the sale of Sequent. As a result of the sale, changes in state apportionment rates resulted in $85 million of additional net state tax expense. See Note 15 under "Southern Company Gas" for additional information. A reconciliation of the federal statutory income tax rate to the effective income tax rate is as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 2.6 5.2 1.5 4.9 (0.7) 7.8 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.7 0.7 0.8 0.4 — — Flowback of excess deferred income taxes (9.2) (19.8) (2.6) (10.2) — (2.6) AFUDC-Equity (1.1) (1.2) (1.2) — — — Federal PTCs (1.2) — (1.4) — (7.4) — ITC amortization (1.3) (0.1) (0.1) — (19.0) — Noncontrolling interests 0.6 — — — 11.1 — Other (0.2) (0.2) (0.3) 0.1 0.1 (0.6) Effective income tax (benefit) rate 11.4 % 5.6 % 17.7 % 16.2 % 5.1 % 25.6 % 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 6.2 4.8 6.5 4.4 1.9 6.4 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.6 0.5 0.6 0.3 — — Flowback of excess deferred income taxes (6.6) (1.9) (9.6) (7.8) — (2.5) AFUDC-Equity (1.1) (0.8) (1.5) — — — Federal PTCs — — — — (6.6) — ITC amortization (1.3) (0.1) (0.1) — (17.2) (0.1) Noncontrolling interests 0.5 — — — 8.4 — Other — 0.3 — 0.3 (0.1) (0.9) Effective income tax (benefit) rate 18.8 % 23.8 % 16.9 % 18.2 % 7.4 % 23.9 % 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 5.5 4.6 (5.7) 4.9 (8.0) 15.1 Employee stock plans' dividend deduction (0.9) — — — — — Non-deductible book depreciation 0.9 0.5 3.1 0.4 — — Flowback of excess deferred income taxes (11.7) (2.6) (49.9) (15.2) — (2.8) AFUDC-Equity (1.5) (0.7) (6.4) — — — Federal PTCs — — — — (4.6) — ITC amortization (2.2) (0.1) (0.4) — (29.7) (0.1) Noncontrolling interests 0.8 — — — 13.4 — Leveraged lease impairments and dispositions (1.4) — — — — — Other (0.1) 0.2 (1.9) 0.6 (0.4) 0.6 Effective income tax (benefit) rate 10.4 % 22.9 % (40.2) % 11.7 % (8.3) % 33.8 % Deferred Tax Assets and Liabilities The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows: December 31, 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,683 $ 2,566 $ 3,628 $ 339 $ 1,346 $ 1,576 Property basis differences 2,647 1,444 812 188 — 189 Employee benefit obligations 979 321 446 49 12 74 AROs 833 476 314 — — — Under recovered fuel and natural gas costs 601 80 508 13 — — Regulatory assets – AROs 1,902 667 1,196 39 — — Employee benefit obligations 797 213 260 37 — 11 Remaining book value of retired assets 369 143 221 5 — — Premium on reacquired debt 63 9 53 1 — — Other 700 182 223 43 2 191 Total deferred income tax liabilities 18,574 6,101 7,661 714 1,360 2,041 Deferred tax assets — AROs 2,735 1,143 1,510 39 — — ITC and PTC carryforwards 1,387 12 691 — 481 — Employee benefit obligations 985 224 316 52 10 89 Estimated loss on plants under construction 857 — 857 — — — Estimated loss on regulatory disallowance 26 — — — — 26 Other state deferred tax attributes 363 — 13 231 49 8 Federal effect of net state deferred tax liabilities 418 215 92 — 27 101 Other property basis differences 197 — 83 — 97 — State effect of federal deferred taxes 115 115 — — — — Other partnership basis differences 85 — — — 85 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 34 30 — 3 — — Long-term debt fair value adjustment 79 — — — — 79 Other comprehensive losses 67 4 4 — 6 — Other 538 188 152 57 18 74 Total deferred income tax assets 7,886 1,931 3,718 382 773 377 Valuation allowance (206) — (75) (41) (27) (7) Net deferred income tax assets 7,680 1,931 3,643 341 746 370 Net deferred income taxes (assets)/liabilities $ 10,894 $ 4,170 $ 4,018 $ 373 $ 614 $ 1,671 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (96) $ — $ — $ (96) $ — $ — Accumulated deferred income taxes – liabilities $ 10,990 $ 4,170 $ 4,018 $ 469 $ 614 $ 1,671 December 31, 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,443 $ 2,564 $ 3,447 $ 338 $ 1,351 $ 1,505 Property basis differences 2,350 1,303 693 179 — 150 Employee benefit obligations 888 284 412 43 11 68 AROs 876 499 324 — — — Under recovered fuel and natural gas costs 805 185 548 40 — 32 Regulatory assets – AROs 2,006 679 1,285 42 — — Employee benefit obligations 677 180 226 30 — 15 Remaining book value of retired assets 400 142 253 5 — — Premium on reacquired debt 66 9 57 — — — Other 555 179 181 40 14 82 Total deferred income tax liabilities 18,066 6,024 7,426 717 1,376 1,852 Deferred tax assets — AROs 2,882 1,178 1,609 42 — — ITC and PTC carryforwards 1,685 12 673 — 794 — Employee benefit obligations 890 198 304 47 9 89 Estimated loss on plants under construction 888 — 888 — — — Other state deferred tax attributes 388 — 12 239 51 7 Federal effect of net state deferred tax liabilities 365 175 88 — 28 92 Other property basis differences 207 — 79 — 109 — State effect of federal deferred taxes 136 136 — — — — Other partnership basis differences 111 — — — 111 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 137 127 — 9 — — Long-term debt fair value adjustment 85 — — — — 85 Other comprehensive losses 72 4 5 — 5 — Other 552 213 186 62 17 28 Total deferred income tax assets 8,398 2,043 3,844 399 1,124 301 Valuation allowance (257) — (125) (41) (27) (9) Net deferred income tax assets 8,141 2,043 3,719 358 1,097 292 Net deferred income taxes (assets)/liabilities $ 9,925 $ 3,981 $ 3,707 $ 359 $ 279 $ 1,560 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (111) $ — $ — $ (107) $ — $ — Accumulated deferred income taxes – liabilities $ 10,036 $ 3,981 $ 3,707 $ 466 $ 279 $ 1,560 The traditional electric operating companies and the natural gas distribution utilities have tax-related regulatory assets (deferred income tax charges) and regulatory liabilities (deferred income tax credits). The regulatory assets are primarily attributable to tax benefits flowed through to customers in prior years, deferred taxes previously recognized at rates lower than the current enacted tax law, and taxes applicable to capitalized interest. The regulatory liabilities are primarily attributable to deferred taxes previously recognized at rates higher than the current enacted tax law and to unamortized ITCs. See Note 2 for each Registrant's related balances at December 31, 2023 and 2022. Tax Credit Carryforwards Federal ITC/PTC carryforwards at December 31, 2023 were as follows: Southern Company Alabama Georgia Southern (in millions) Federal ITC/PTC carryforwards $ 829 $ 12 $ 131 $ 481 Tax year in which federal ITC/PTC carryforwards begin expiring 2031 2032 2031 2035 Year by which federal ITC/PTC carryforwards are expected to be utilized 2029 2028 2028 2029 The estimated tax credit utilization reflects the various transactions described in Note 15 and could be impacted by numerous factors, including the acquisition of additional renewable projects, changes in taxable income projections, transfer of eligible credits, potential income tax rate changes, and the ultimate implementation of the natural gas safe harbor method for repairs. In the third quarter 2023, Georgia Power started generating advanced nuclear PTCs for Plant Vogtle Unit 3 beginning on the in-service date of July 31, 2023. In addition, pursuant to the Global Amendments to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Joint Owner Contracts"), Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Unit 3 from the other Vogtle Owners. See Note 2 under "Georgia Power – Nuclear Construction" for additional information on Plant Vogtle Units 3 and 4. At December 31, 2023, Georgia Power also had approximately $452 million in net state investment and other net state tax credit carryforwards for the State of Georgia that will expire between tax years 2023 and 2032 and are not expected to be fully utilized. Georgia Power has a net state valuation allowance of $60 million associated with these carryforwards. The ultimate outcome of these matters cannot be determined at this time. Net Operating Loss Carryforwards At December 31, 2023, the net state income tax benefit of state and local NOL carryforwards for Southern Company's subsidiaries were as follows: Company/Jurisdiction Approximate Net State Income Tax Benefit of NOL Carryforwards Tax Year NOL (in millions) Mississippi Power Mississippi $ 183 2032 Southern Power Oklahoma 26 2035 Florida 10 2034 Other states 2 Various Southern Power Total $ 38 Other () New York 11 2036 New York City 14 2036 Other states 30 Various Southern Company Total $ 276 () Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2023. State NOLs for Mississippi, Oklahoma, and Florida are not expected to be fully utilized prior to expiration. At December 31, 2023, Mississippi Power had a net state valuation allowance of $32 million for the Mississippi NOL, Southern Power had net state valuation allowances of $11 million for the Oklahoma NOL and $10 million for the Florida NOL, and Southern Company had a net valuation allowance of $25 million for the New York and New York City NOLs. The ultimate outcome of these matters cannot be determined at this time. Unrecognized Tax Benefits Changes in unrecognized tax benefits for the periods presented were as follows: Southern Company Georgia Power Southern (in millions) Unrecognized tax benefits at December 31, 2020 $ 44 $ — $ — Tax positions changes – Increase from prior periods 3 — — Unrecognized tax benefits at December 31, 2021 47 — — Tax positions changes – Increase from prior periods 33 — 32 Unrecognized tax benefits at December 31, 2022 80 — 32 Tax positions changes – Increase from prior periods 88 86 2 Statute of limitations expiration (52) (9) — Unrecognized tax benefits at December 31, 2023 $ 116 $ 77 $ 34 The unrecognized tax positions increase from prior periods for 2022 is primarily related to the amendment of certain 2018 state tax filing positions related to Southern Company Gas dispositions. If accepted by the states, these positions would decrease Southern Company's and Southern Company Gas' annual effective tax rates. The ultimate outcome of these unrecognized tax benefits is dependent on acceptance by each state and is not expected to be resolved within the next 12 months. The unrecognized tax positions increase from prior periods for 2023 are primarily related to the amendment of certain 2019 through 2021 state tax filing positions related to tax credit utilization, a portion of which decreased in the fourth quarter 2023 due to a statute of limitations expiration. If effective settlement of the positions is favorable, these positions would decrease Southern Company's and Georgia Power's annual effective tax rates. The ultimate outcome of this unrecognized tax benefit, of which a portion is expected to be resolved within the next 12 months, is dependent on acceptance by the state or expiration of related statute of limitations. The unrecognized tax positions reductions due to statute of limitations expiration for 2023 primarily relates to a 2019 state tax filing position to exclude certain gains from 2019 dispositions from taxation in a certain unitary state. This tax position and related interest was recognized in the fourth quarter 2023 and decreased Southern Company's annual effective tax rate. All of the Registrants classify interest on tax uncertainties as interest expense. Accrued interest for all tax positions was immaterial for all years presented. None of the Registrants accrued any penalties on uncertain tax positions. The IRS has finalized its audits of Southern Company's consolidated federal income tax returns through 2022. Southern Company is a participant in the Compliance Assurance Process of the IRS. The IRS has selected six Southern Power partnership returns for exam for the 2020 and 2021 tax years. The ultimate outcome of this matter cannot be determined at this time. The audits for the Registrants' state income tax returns have either been concluded, or the statute of limitations has expired, for years prior to 2015.

RETIREMENT BENEFITS

RETIREMENT BENEFITS	12 Months Ended
RETIREMENT BENEFITS	Dec. 31, 2023
Retirement Benefits [Abstract]
RETIREMENT BENEFITS	RETIREMENT BENEFITS The Southern Company system has a qualified defined benefit, trusteed pension plan covering substantially all employees, with the exception of PowerSecure employees. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). No contributions to the qualified pension plan were made for the year ended December 31, 2023 and no mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2024. The Southern Company system also provides certain non-qualified defined benefits for a select group of management and highly compensated employees, which are funded on a cash basis. In addition, the Southern Company system provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The traditional electric operating companies fund other postretirement trusts to the extent required by their respective regulatory commissions. Southern Company Gas has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses. For the year ending December 31, 2024, no contributions to any other postretirement trusts are expected. Actuarial Assumptions The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below. 2023 Assumptions used to determine net Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Discount rate – interest costs 5.13 5.14 5.12 5.12 5.19 5.12 Discount rate – service costs 5.36 5.38 5.38 5.37 5.37 5.31 Expected long-term return on plan assets 8.40 8.40 8.40 8.40 8.40 8.40 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Discount rate – interest costs 5.08 5.09 5.07 5.08 5.12 5.07 Discount rate – service costs 5.34 5.35 5.34 5.33 5.33 5.33 Expected long-term return on plan assets 7.67 7.95 7.49 7.43 — 6.59 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2022 Assumptions used to determine net Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Discount rate – interest costs 2.55 2.58 2.51 2.54 2.79 2.53 Discount rate – service costs 3.34 3.36 3.37 3.35 3.36 3.21 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Discount rate – interest costs 2.32 2.38 2.30 2.27 2.55 2.17 Discount rate – service costs 3.26 3.30 3.27 3.26 3.25 3.22 Expected long-term return on plan assets 7.21 7.54 6.88 7.22 — 6.08 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine net periodic costs: Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 2.81 % 2.85 % 2.79 % 2.80 % 2.99 % 2.75 % Discount rate – interest costs 2.13 2.17 2.09 2.12 2.46 2.10 Discount rate – service costs 3.18 3.23 3.21 3.20 3.22 2.97 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.56 % 2.63 % 2.52 % 2.53 % 2.78 % 2.46 % Discount rate – interest costs 1.84 1.91 1.82 1.78 2.12 1.64 Discount rate – service costs 3.07 3.13 3.08 3.06 3.05 3.01 Expected long-term return on plan assets 7.09 7.18 6.84 6.98 — 6.54 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2023 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.07 % 5.08 % 5.06 % 5.06 % 5.14 % 5.05 % Annual salary increase 4.60 4.60 4.60 4.60 4.60 4.60 Other postretirement benefit plans Discount rate 4.99 % 5.01 % 4.98 % 4.98 % 5.06 % 4.98 % Annual salary increase 4.60 4.60 4.60 4.60 4.60 4.60 2022 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 The Registrants estimate the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of the different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio. The Registrants set the expected rate of return assumption using an arithmetic mean which represents the expected simple average return to be earned by the pension plan assets over any one year. The Registrants believe the use of the arithmetic mean is more compatible with the expected rate of return's function of estimating a single year's investment return. An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2023 were as follows: Initial Cost Trend Rate Ultimate Cost Trend Rate Year That Ultimate Rate is Reached Pre-65 7.00 % 4.50 % 2032 Post-65 medical 5.50 4.50 2032 Post-65 prescription 8.50 4.50 2032 Pension Plans The total accumulated benefit obligation for the pension plans at December 31, 2023 and 2022 was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2023 $ 11,991 $ 2,746 $ 3,674 $ 546 $ 145 $ 808 December 31, 2022 11,422 2,601 3,534 520 135 801 An actuarial loss of $0.5 billion and an actuarial gain of $3.9 billion were recorded for the annual remeasurement of the Southern Company system pension plans at December 31, 2023 and 2022, respectively, primarily due to a decrease of 18 basis points and an increase of 216 basis points, respectively, in the overall discount rate used to calculate the benefit obligation as a result of higher market interest rates. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2023 and 2022 were as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 12,602 $ 2,906 $ 3,851 $ 569 $ 163 $ 868 Service cost 275 64 68 11 6 24 Interest cost 626 145 191 28 8 42 Benefits paid (744) (155) (224) (32) (6) (104) Actuarial loss 493 116 123 23 6 52 Balance at end of year 13,252 3,076 4,009 599 177 882 Change in plan assets Fair value of plan assets at beginning of year 14,218 3,427 4,456 649 178 1,002 Actual return on plan assets 1,092 260 331 50 12 79 Employer contributions 52 11 9 2 2 3 Benefits paid (744) (154) (225) (32) (7) (104) Fair value of plan assets at end of year 14,618 3,544 4,571 669 185 980 Accrued asset $ 1,366 $ 468 $ 562 $ 70 $ 8 $ 98 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,382 $ 3,806 $ 5,012 $ 743 $ 222 $ 1,134 Service cost 412 99 103 17 9 34 Interest cost 408 96 123 18 6 28 Benefits paid (692) (144) (226) (30) (5) (75) Actuarial gain (3,908) (951) (1,161) (179) (69) (253) Balance at end of year 12,602 2,906 3,851 569 163 868 Change in plan assets Fair value of plan assets at beginning of year 17,225 4,141 5,415 786 213 1,241 Actual loss on plan assets (2,376) (579) (753) (110) (31) (167) Employer contributions 61 9 20 3 1 3 Benefits paid (692) (144) (226) (30) (5) (75) Fair value of plan assets at end of year 14,218 3,427 4,456 649 178 1,002 Accrued asset $ 1,616 $ 521 $ 605 $ 80 $ 15 $ 134 The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2023 are shown in the following table. All pension plan assets are related to the qualified pension plan. Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Projected benefit obligations: Qualified pension plan $ 12,540 $ 2,959 $ 3,865 $ 569 $ 154 $ 822 Non-qualified pension plan 713 117 145 29 22 60 Amounts recognized in the balance sheets at December 31, 2023 and 2022 related to the Registrants' pension plans consist of the following: Southern Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2023: Prepaid pension costs (a) $ 2,079 $ 585 $ 706 $ 99 $ 31 $ 158 Other regulatory assets, deferred (b) 2,960 821 1,051 152 — 143 Other current liabilities (64) (11) (13) (2) (2) (3) Employee benefit obligations (c) (649) (106) (131) (27) (21) (58) Other regulatory liabilities, deferred (47) — — — — — AOCI 79 — — — 20 (45) December 31, 2022: Prepaid pension costs (a) $ 2,290 $ 629 $ 738 $ 108 $ 37 $ 183 Other regulatory assets, deferred (b) 2,455 679 887 123 — 111 Other current liabilities (56) (10) (12) (2) (2) (3) Employee benefit obligations (c) (618) (98) (121) (26) (20) (42) Other regulatory liabilities, deferred (85) — — — — — AOCI 24 — — — 11 (75) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in regulatory assets at December 31, 2023 and 2022 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2023 Regulatory assets: Prior service cost $ 9 $ 4 $ 6 $ 1 $ (7) Net loss 2,904 817 1,045 151 100 Regulatory amortization — — — — 50 Total regulatory assets () $ 2,913 $ 821 $ 1,051 $ 152 $ 143 Balance at December 31, 2022 Regulatory assets: Prior service cost $ 10 $ 4 $ 7 $ 1 $ (9) Net loss 2,361 675 880 122 66 Regulatory amortization — — — — 54 Total regulatory assets () $ 2,371 $ 679 $ 887 $ 123 $ 111 () Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2023 and 2022 are presented in the following table: Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Regulatory assets (liabilities): () Balance at December 31, 2021 $ 2,801 $ 809 $ 971 $ 146 $ 91 Net (gain) loss (183) (67) (9) (12) 27 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net gain (loss) (246) (62) (74) (11) 1 Amortization of regulatory assets () — — — — (10) Total reclassification adjustments (247) (63) (75) (11) (7) Total change (430) (130) (84) (23) 20 Balance at December 31, 2022 $ 2,371 $ 679 $ 887 $ 123 $ 111 Net loss 576 153 178 31 34 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net loss (33) (10) (13) (2) — Amortization of regulatory assets () — — — — (4) Total reclassification adjustments (34) (11) (14) (2) (2) Total change 542 142 164 29 32 Balance at December 31, 2023 $ 2,913 $ 821 $ 1,051 $ 152 $ 143 () Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. Presented below are the amounts included in AOCI at December 31, 2023 and 2022 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Southern Southern Company (in millions) Balance at December 31, 2023 AOCI: Prior service cost $ (1) $ — $ (2) Net (gain) loss 80 20 (43) Total AOCI $ 79 $ 20 $ (45) Balance at December 31, 2022 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 26 11 (72) Total AOCI $ 24 $ 11 $ (75) The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Southern Southern Company (in millions) AOCI: Balance at December 31, 2021 $ 100 $ 35 $ (45) Net gain (82) (22) (30) Reclassification adjustments: Amortization of net gain (loss) 6 (2) — Total change (76) (24) (30) Balance at December 31, 2022 $ 24 $ 11 $ (75) Net loss 62 9 29 Reclassification adjustments: Amortization of prior service costs 1 — 1 Amortization of net loss (8) — — Total reclassification adjustments (7) — 1 Total change 55 9 30 Balance at December 31, 2023 $ 79 $ 20 $ (45) Components of net periodic pension cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Service cost $ 275 $ 64 $ 68 $ 11 $ 6 $ 24 Interest cost 626 145 191 28 8 42 Expected return on plan assets (1,229) (297) (385) (56) (15) (85) Recognized net (gain) loss 32 9 13 2 — (5) Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (296) $ (78) $ (112) $ (15) $ (1) $ (12) 2022 Service cost $ 412 $ 99 $ 103 $ 17 $ 9 $ 34 Interest cost 408 96 123 18 6 28 Expected return on plan assets (1,265) (306) (399) (57) (15) (91) Recognized net loss 240 62 75 11 2 8 Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (205) $ (48) $ (97) $ (11) $ 2 $ (9) 2021 Service cost $ 434 $ 102 $ 112 $ 18 $ 10 $ 37 Interest cost 346 82 104 16 5 24 Expected return on plan assets (1,191) (287) (375) (55) (14) (86) Recognized net loss 314 82 100 15 3 13 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (96) $ (20) $ (58) $ (6) $ 4 $ — The service cost component of net periodic pension cost is included in operations and maintenance expenses and all other components of net periodic pension cost are included in other income (expense), net in the Registrants' statements of income. Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Registrants have elected to amortize changes in the market value of return-seeking plan assets over five years and to recognize the changes in the market value of liability-hedging plan assets immediately. Given the significant concentration in return-seeking plan assets, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets. Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2023, estimated benefit payments were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit Payments: 2024 $ 748 $ 164 $ 241 $ 33 $ 7 $ 57 2025 776 171 248 34 7 59 2026 801 177 254 36 8 60 2027 822 182 257 37 8 62 2028 840 187 260 38 7 64 2029 to 2033 4,417 988 1,337 201 47 336 Other Postretirement Benefits Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2023 and 2022 were as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,441 $ 344 $ 514 $ 59 $ 9 $ 179 Service cost 15 4 4 1 — 1 Interest cost 70 17 25 3 — 9 Benefits paid (107) (24) (36) (4) (1) (18) Actuarial (gain) loss (33) (12) (18) (2) 1 1 Balance at end of year 1,386 329 489 57 9 172 Change in plan assets Fair value of plan assets at beginning of year 998 372 368 24 — 113 Actual return on plan assets 131 52 51 2 — 19 Employer contributions 73 3 27 3 1 14 Benefits paid (107) (24) (36) (4) (1) (18) Fair value of plan assets at end of year 1,095 403 410 25 — 128 Accrued asset (liability) $ (291) $ 74 $ (79) $ (32) $ (9) $ (44) 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,849 $ 440 $ 656 $ 76 $ 11 $ 237 Service cost 23 6 6 1 — 1 Interest cost 42 10 15 2 — 5 Benefits paid (109) (23) (38) (4) (1) (18) Actuarial gain (365) (89) (125) (16) (1) (46) Retiree drug subsidy 1 — — — — — Balance at end of year 1,441 344 514 59 9 179 Change in plan assets Fair value of plan assets at beginning of year 1,251 489 450 29 — 143 Actual loss on plan assets (218) (98) (71) (4) — (25) Employer contributions 73 4 27 3 1 13 Benefits paid (108) (23) (38) (4) (1) (18) Fair value of plan assets at end of year 998 372 368 24 — 113 Accrued asset (liability) $ (443) $ 28 $ (146) $ (35) $ (9) $ (66) Amounts recognized in the balance sheets at December 31, 2023 and 2022 related to the Registrants' other postretirement benefit plans consist of the following: Southern Company Alabama Power Georgia Mississippi Power Southern Southern Company Gas (in millions) December 31, 2023: Prepaid other postretirement benefit costs (a) $ — $ 74 $ — $ — $ — $ — Other regulatory assets, deferred (b) 23 — 11 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (285) — (79) (32) (8) (44) Other regulatory liabilities, deferred (231) (48) (85) (10) — (68) AOCI (9) — — — 1 (10) December 31, 2022: Prepaid other postretirement benefit costs (a) $ — $ 28 $ — $ — $ — $ — Other regulatory assets, deferred (b) 34 — 19 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (437) — (146) (35) (8) (66) Other regulatory liabilities, deferred (170) (21) (58) (9) — (58) AOCI (4) — — — — (2) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2023 and 2022 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2023: Regulatory assets (liabilities): Prior service cost $ 13 $ 4 $ 5 $ 1 $ — Net gain (216) (52) (79) (11) (64) Regulatory amortization — — — — (4) Total regulatory assets (liabilities) () $ (203) $ (48) $ (74) $ (10) $ (68) Balance at December 31, 2022: Regulatory assets (liabilities): Prior service cost $ 14 $ 4 $ 6 $ 1 $ 1 Net gain (150) (25) (45) (10) (64) Regulatory amortization — — — — 5 Total regulatory assets (liabilities) () $ (136) $ (21) $ (39) $ (9) $ (58) () Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Net regulatory assets (liabilities): () Balance at December 31, 2021 $ (74) $ (62) $ (10) $ 1 $ (34) Net (gain) loss (64) 41 (27) (10) (13) Reclassification adjustments: Amortization of prior service costs 1 — — — — Amortization of net gain (loss) 1 — (2) — — Amortization of regulatory assets () — — — — (11) Total reclassification adjustments 2 — (2) — (11) Total change (62) 41 (29) (10) (24) Balance at December 31, 2022 $ (136) $ (21) $ (39) $ (9) $ (58) Net gain (77) (30) (38) (1) — Reclassification adjustments: Amortization of prior service costs (1) — (1) — — Amortization of net gain 6 3 4 — — Amortization of regulatory assets () — — — — (10) Total reclassification adjustments 5 3 3 — (10) Total change (72) (27) (35) (1) (10) Balance at December 31, 2023 $ (208) $ (48) $ (74) $ (10) $ (68) () Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. Presented below are the amounts included in AOCI at December 31, 2023 and 2022 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Southern Southern Company (in millions) Balance at December 31, 2023 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (10) 1 (10) Total AOCI $ (9) $ 1 $ (10) Balance at December 31, 2022 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (5) — (2) Total AOCI $ (4) $ — $ (2) The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Southern Southern Company Gas (in millions) AOCI: Balance at December 31, 2021 $ — $ 2 $ (5) Net gain (3) (2) — Reclassification adjustments: Amortization of net gain (loss) (1) — 3 Total change (4) (2) 3 Balance at December 31, 2022 $ (4) $ — $ (2) Net (gain) loss (12) 1 — Reclassification adjustments: Amortization of net gain (loss) 7 — (8) Total change (5) 1 (8) Balance at December 31, 2023 $ (9) $ 1 $ (10) Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Service cost $ 15 $ 4 $ 4 $ 1 $ — $ 1 Interest cost 70 17 25 3 — 9 Expected return on plan assets (83) (33) (29) (3) 1 (10) Net amortization (11) (3) (3) — — 6 Net periodic postretirement benefit cost (income) $ (9) $ (15) $ (3) $ 1 $ 1 $ 6 2022 Service cost $ 23 $ 6 $ 6 $ 1 $ — $ 1 Interest cost 42 10 15 2 — 5 Expected return on plan assets (80) (32) (28) (2) 1 (9) Net amortization (1) — 2 — — 6 Net periodic postretirement benefit cost (income) $ (16) $ (16) $ (5) $ 1 $ 1 $ 3 2021 Service cost $ 24 $ 6 $ 7 $ 1 $ — $ 2 Interest cost 35 9 12 1 — 4 Expected return on plan assets (76) (30) (26) (1) 1 (10) Net amortization 2 — 2 — — 6 Net periodic postretirement benefit cost (income) $ (15) $ (15) $ (5) $ 1 $ 1 $ 2 The service cost component of net periodic postretirement benefit cost is included in operations and maintenance expenses and all other components of net periodic postretirement benefit cost are included in other income (expense), net in the Registrants' statements of income. The Registrants' future benefit payments, including prescription drug benefits, are provided in the table below. These amounts reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit payments: 2024 $ 111 $ 24 $ 40 $ 5 $ 1 $ 17 2025 109 24 39 5 1 17 2026 108 24 38 5 1 16 2027 108 24 38 5 1 16 2028 108 25 38 4 1 15 2029 to 2033 523 123 188 21 1 64 Benefit Plan Assets Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code. The Registrants' investment policies for both the pension plans and the other postretirement benefit plans cover a diversified mix of assets as described below. Derivative instruments may be used to gain efficient exposure to the various asset classes and as hedging tools. Additionally, the Registrants minimize the risk of large losses primarily through diversification but also monitor and manage other aspects of risk. The investment strategy for plan assets related to the Southern Company system's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Southern Company system employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices. Management believes the portfolio is well-diversified with no significant concentrations of risk. Investment Strategies and Benefit Plan Asset Fair Values A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below: Description Valuation Methodology Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches. International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches. Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market, but are classified as Level 2. Fixed income: A mix of domestic and international bonds. Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument. Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities. Real estate: Investments in equity or debt of real properties and in publicly traded real estate securities. Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature. Private equity: Investments in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt. Private credit: Investments focused on debt instruments, of which returns are driven by income rather than capital appreciation. Infrastructure: Investments in real assets, typically with long-term, predictable, and stable cash flows and a meaningful income component. Investments in real estate, special situations, private equity, private credit, and infrastructure are typically invested in private partnerships and/or other pooled vehicles (Funds) which are generally classified as Net Asset Value as a Practical Expedient, since the Funds and underlying assets are not publicly traded and/or often have liquidity restrictions. The managers of the Funds value the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The total market value of each of the Funds is determined by aggregating the value of the underlying assets less liabilities. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate. The fair values presented herein exclude cash, receivables related to investment income and pending investment sales, and payables related to pending investment purchases. The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2023 and 2022 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 41 % 40 % Domestic equity $ 1,959 $ 771 $ — $ — $ 2,730 International equity 1,947 1,052 — — 2,999 Fixed income: 30 32 U.S. Treasury, government, and ag

STOCK COMPENSATION

STOCK COMPENSATION	12 Months Ended
STOCK COMPENSATION	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
STOCK COMPENSATION	STOCK COMPENSATION Stock-based compensation primarily in the form of Southern Company performance share units (PSU) and restricted stock units (RSU) may be granted through the Equity and Incentive Compensation Plan to Southern Company system employees ranging from line management to executives. At December 31, 2023, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Number of employees 1,401 191 210 42 40 193 The majority of PSUs and RSUs awarded contain terms where employees become immediately vested in PSUs and RSUs upon retirement. As a result, compensation expense for employees that are retirement eligible at the grant date is recognized immediately, while compensation expense for employees that become retirement eligible during the vesting period is recognized over the period from grant date to the date of retirement eligibility. In addition, the Registrants recognize forfeitures as they occur. All unvested PSUs and RSUs vest immediately upon a change in control where Southern Company is not the surviving corporation. Performance Share Units PSUs granted to employees vest at the end of a three-year performance period. Shares of Southern Company common stock are delivered to employees at the end of the performance period with the number of shares issued ranging from 0% to 200% of the target number of PSUs granted, based on achievement of the performance goals established by the Compensation Committee of the Southern Company Board of Directors. Southern Company has issued two types of PSUs, each with a unique performance goal. These types of PSUs include total shareholder return (TSR) awards based on the TSR for Southern Company common stock during the three The fair value of TSR awards is determined as of the grant date using a Monte Carlo simulation model. In determining the fair value of the TSR awards issued to employees, the expected volatility is based on the historical volatility of Southern Company's stock over a period equal to the performance period. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant that covers the performance period of the awards. The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted: Year Ended December 31 2023 2022 2021 Expected volatility 30.0% 29.6% 30.0% Expected term (in years) 3 3 3 Interest rate 3.8% 1.7% 0.2% Weighted average grant-date fair value $76.83 $79.69 $69.06 The Registrants recognize TSR award compensation expense on a straight-line basis over the three-year performance period without remeasurement. The fair values of ROE awards are based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair value of the ROE awards granted during 2023, 2022, and 2021 was $68.93, $66.87, and $59.49, respectively. Compensation expense for ROE awards is generally recognized ratably over the three-year performance period adjusted for expected changes in ROE performance. Total compensation cost recognized for vested ROE awards reflects final performance metrics. Southern Company had 2.4 million unvested PSUs outstanding at December 31, 2022. In February 2023, the PSUs that vested for the three-year performance period ended December 31, 2022 were converted into 1.8 million shares outstanding at a share price of $67.13. During 2023, Southern Company granted 1.3 million PSUs and 1.3 million PSUs were vested or forfeited, resulting in 2.4 million unvested PSUs outstanding at December 31, 2023. In February 2024, the PSUs that vested for the three-year performance period ended December 31, 2023 were converted into 2.3 million shares outstanding at a weighted average share price of $66.95. Total PSU compensation cost, and the related tax benefit recognized in income, for the years ended December 31, 2023, 2022, and 2021 are as follows: 2023 2022 2021 (in millions) Southern Company Compensation cost recognized in income $ 107 $ 101 $ 112 Tax benefit of compensation cost recognized in income 28 26 29 Southern Company Gas Compensation cost recognized in income $ 14 $ 12 $ 17 Tax benefit of compensation cost recognized in income 4 4 4 Total PSU compensation cost and the related tax benefit recognized in income were immaterial for all periods presented for all other Registrants. The compensation cost related to the grant of Southern Company PSUs to the employees of each Subsidiary Registrant is recognized in each Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company. At December 31, 2023, Southern Company's total unrecognized compensation cost related to PSUs was $32 million and is expected to be recognized over a weighted-average period of approximately 19 months. The total unrecognized compensation cost related to PSUs at December 31, 2023 was immaterial for all other Registrants. Restricted Stock Units The fair value of RSUs is based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair values of RSUs granted during 2023, 2022, and 2021 were $68.95, $67.20, and $59.56, respectively. For most RSU awards, one-third of the RSUs vest each year throughout a three-year service period and compensation cost for RSUs is generally recognized over the corresponding one two Southern Company had 0.9 million RSUs outstanding at December 31, 2022. During 2023, Southern Company granted 0.5 million RSUs and 0.5 million RSUs were vested or forfeited, resulting in 0.9 million unvested RSUs outstanding at December 31, 2023, including RSUs related to employee retention agreements. For the years ended December 31, 2023, 2022, and 2021, Southern Company's total compensation cost for RSUs recognized in income was $30 million, $26 million, and $32 million, respectively. The related tax benefit also recognized in income was $8 million, $7 million, and $8 million for the years ended December 31, 2023, 2022, and 2021, respectively. Total unrecognized compensation cost related to RSUs at December 31, 2023, which is being recognized over a weighted-average period of approximately 17 months, is immaterial for Southern Company. Total RSUs outstanding and total compensation cost and related tax benefit for the RSUs recognized in income for the years ended December 31, 2023, 2022, and 2021, as well as the total unrecognized compensation cost at December 31, 2023, were immaterial for all other Registrants. The compensation cost related to the grant of Southern Company RSUs to the employees of each Subsidiary Registrant is recognized in such Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company. Stock Options In 2015, Southern Company discontinued granting stock options. As of December 31, 2017, all stock option awards were vested and compensation cost fully recognized. Stock options expire no later than 10 years after the grant date and the latest possible exercise will occur by November 2024. At December 31, 2023, the weighted average remaining contractual term for the options outstanding and exercisable was approximately 2 months. Southern Company's activity in the stock option program for 2023 is summarized below: Shares Subject to Option Weighted Average Exercise Price (in millions) Outstanding at December 31, 2022 1.0 $ 42.22 Exercised 0.7 42.54 Outstanding and Exercisable at December 31, 2023 0.3 $ 41.58 Southern Company's cash receipts from issuances related to stock options exercised under the share-based payment arrangements for the years ended December 31, 2023, 2022, and 2021 were $28 million, $75 million, and $66 million, respectively. At December 31, 2023, the aggregate intrinsic value for options outstanding and exercisable was immaterial for all Registrants. Total intrinsic value of options exercised, and the related tax benefit, for the years ended December 31, 2023, 2022, and 2021 are presented below for Southern Company and were immaterial for all other Registrants: Year Ended December 31 2023 2022 2021 (in millions) Southern Company Intrinsic value of options exercised $ 18 $ 49 $ 34 Tax benefit of options exercised 4 12 7

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
FAIR VALUE MEASUREMENTS	Dec. 31, 2023
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement. • Level 1 consists of observable market data in an active market for identical assets or liabilities. • Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable. • Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information. In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported. Net asset value as a practical expedient is the classification used for assets that do not have readily determined fair values. Fund managers value the assets using various inputs and techniques depending on the nature of the underlying investments. At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 6 $ 49 $ — $ — $ 55 Investments in trusts: (b) Domestic equity 764 216 — — 980 Foreign equity 145 171 — — 316 U.S. Treasury and government agency securities — 369 — — 369 Municipal bonds — 48 — — 48 Pooled funds – fixed income — 6 — — 6 Corporate bonds — 389 — — 389 Mortgage and asset backed securities — 89 — — 89 Private equity — — — 169 169 Cash and cash equivalents 3 — — — 3 Other 58 3 — 9 70 Cash equivalents and restricted cash 253 15 — — 268 Other investments 9 27 8 — 44 Total $ 1,238 $ 1,382 $ 8 $ 178 $ 2,806 Liabilities: Energy-related derivatives (a) $ 46 $ 312 $ — $ — $ 358 Interest rate derivatives — 264 — — 264 Foreign currency derivatives — 122 — — 122 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 49 $ 711 $ 16 $ — $ 776 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Nuclear decommissioning trusts: (b) Domestic equity 443 208 — — 651 Foreign equity 145 — — — 145 U.S. Treasury and government agency securities — 20 — — 20 Municipal bonds — 1 — — 1 Corporate bonds — 231 — — 231 Mortgage and asset backed securities — 25 — — 25 Private equity — — — 169 169 Other 8 — — 9 17 Cash equivalents and restricted cash 119 15 — — 134 Other investments — 27 — — 27 Total $ 715 $ 542 $ — $ 178 $ 1,435 Liabilities: Energy-related derivatives $ — $ 110 $ — $ — $ 110 Georgia Power Assets: Energy-related derivatives $ — $ 13 $ — $ — $ 13 Nuclear decommissioning trusts: (b) Domestic equity 321 1 — — 322 Foreign equity — 170 — — 170 U.S. Treasury and government agency securities — 349 — — 349 Municipal bonds — 47 — — 47 Corporate bonds — 158 — — 158 Mortgage and asset backed securities — 64 — — 64 Other 50 3 — — 53 Total $ 371 $ 805 $ — $ — $ 1,176 Liabilities: Energy-related derivatives $ — $ 124 $ — $ — $ 124 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Cash equivalents 17 — — — 17 Total $ 17 $ 15 $ — $ — $ 32 Liabilities: Energy-related derivatives $ — $ 61 $ — $ — $ 61 Southern Power Assets: Energy-related derivatives $ — $ 3 $ — $ — $ 3 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Foreign currency derivatives — 22 — — 22 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 3 $ 40 $ 16 $ — $ 59 Southern Company Gas Assets: Energy-related derivatives (a) $ 6 $ 3 $ — $ — $ 9 Non-qualified deferred compensation trusts: Domestic equity — 7 — — 7 Foreign equity — 1 — — 1 Pooled funds - fixed income — 6 — — 6 Cash and cash equivalents 3 — — — 3 Total $ 9 $ 17 $ — $ — $ 26 Liabilities: Energy-related derivatives (a)(b) $ 46 $ 12 $ — $ — $ 58 Interest rate derivatives — 79 — — 79 Total $ 46 $ 91 $ — $ — $ 137 (a) Excludes cash collateral of $62 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information. Valuation Methodologies The energy-related derivatives primarily consist of exchange-traded and over-the-counter financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard over-the-counter products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used. For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available. The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information. Southern Power has contingent payment obligations related to two of its acquisitions whereby it is primarily obligated to make generation-based payments to the seller, commencing at the commercial operation of each facility and continuing through 2026 and 2035, respectively. The obligations are primarily categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility's generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of contingent consideration reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial. Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments. "Other investments" primarily includes investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds. The fair value measurements of private market investments held in Alabama Power's nuclear decommissioning trusts that are calculated at net asset value per share (or its equivalent) as a practical expedient totaled $178 million and $161 million at December 31, 2023 and 2022, respectively. Unfunded commitments related to the private market investments totaled $87 million and $78 million at December 31, 2023 and 2022, respectively. Private market investments include high-quality private equity funds across several market sectors, funds that invest in real estate assets, and a private credit fund. Private market funds do not have redemption rights. Distributions from these funds will be received as the underlying investments in the funds are liquidated. At December 31, 2023 and 2022, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company () Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas () (in billions) At December 31, 2023: Long-term debt, including securities due within one year: Carrying amount $ 59.4 $ 11.2 $ 16.5 $ 1.6 $ 2.7 $ 7.8 Fair value 55.0 10.1 15.1 1.4 2.6 6.8 At December 31, 2022: Long-term debt, including securities due within one year: Carrying amount $ 54.6 $ 10.6 $ 14.7 $ 1.5 $ 3.0 $ 7.4 Fair value 48.6 9.2 13.0 1.3 2.8 6.5 (*) The carrying amount of Southern Company Gas' long-term debt includes fair value adjustments from the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043. The fair values are determined using Level 2 measurements and are based on quoted market prices for the same or similar issues or on the current rates available to the Registrants.

DERIVATIVES

DERIVATIVES	12 Months Ended
DERIVATIVES	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES	DERIVATIVES The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. For the traditional electric operating companies, Southern Power, and Southern Company Gas' other businesses, each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information. See Note 15 under "Southern Company Gas" for additional information regarding the sale of Sequent. Energy-Related Derivatives The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations. Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in operating revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in operating revenues. Energy-related derivative contracts are accounted for under one of three methods: • Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism. • Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions. • Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered. At December 31, 2023, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows: Net Longest Longest (in millions) Southern Company () 448 2030 2028 Alabama Power 118 2026 — Georgia Power 128 2026 — Mississippi Power 93 2028 — Southern Power 7 2030 2024 Southern Company Gas () 102 2027 2028 () Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 112 million mmBtu and short natural gas positions of 10 million mmBtu at December 31, 2023, which is also included in Southern Company's total volume. In addition to the volumes discussed above, the traditional electric operating companies and Southern Power enter into physical natural gas supply contracts that provide the option to sell back excess natural gas due to operational constraints. The maximum expected volume of natural gas subject to such a feature is 12 million mmBtu for Southern Company, which includes 3 million mmBtu for Alabama Power, 4 million mmBtu for Georgia Power, 2 million mmBtu for Mississippi Power, and 3 million mmBtu for Southern Power. For cash flow hedges of energy-related derivatives, the estimated pre-tax gains (losses) expected to be reclassified from AOCI to earnings for the year ending December 31, 2024 are $(37) million for Southern Company, $(4) million for Southern Power, and $(33) million for Southern Company Gas. Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. At December 31, 2023, the following interest rate derivatives were outstanding: Notional Weighted Average Interest Rate Paid Interest Hedge Fair Value (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 150 4.01% N/A April 2024 $ — Mississippi Power 75 3.84% N/A June 2024 — Mississippi Power 75 4.04% N/A June 2024 — Fair Value Hedges of Existing Debt Southern Company parent 400 1-month SOFR + 0.80% 1.75% March 2028 (46) Southern Company parent 1,000 1-month SOFR + 2.48% 3.70% April 2030 (139) Southern Company Gas 500 1-month SOFR + 0.49% 1.75% January 2031 (79) Southern Company $ 2,200 $ (264) For cash flow hedges of interest rate derivatives, the estimated pre-tax losses expected to be reclassified from AOCI to interest expense for the year ending December 31, 2024 are $19 million for Southern Company and immaterial for the traditional electric operating companies and Southern Company Gas. Deferred gains and losses related to interest rate derivatives are expected to be amortized into earnings through 2054 for Southern Company, Georgia Power, and Mississippi Power, 2052 for Alabama Power, and 2046 for Southern Company Gas. Foreign Currency Derivatives Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI. At December 31, 2023, the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 564 3.78% € 500 1.85% June 2026 $ (22) Fair Value Hedges of Existing Debt Southern Company parent 1,476 3.39% 1,250 1.88% September 2027 (100) Southern Company $ 2,040 € 1,750 $ (122) For cash flow hedges of foreign currency derivatives, the estimated pre-tax losses expected to be reclassified from AOCI to earnings for the year ending December 31, 2024 are $11 million for Southern Power. Derivative Financial Statement Presentation and Amounts The Registrants enter into derivative contracts that may contain certain provisions that permit intra-contract netting of derivative receivables and payables for routine billing and offsets related to events of default and settlements. Southern Company and certain subsidiaries also utilize master netting agreements to mitigate exposure to counterparty credit risk. These agreements may contain provisions that permit netting across product lines and against cash collateral. The fair value amounts of derivative assets and liabilities on the balance sheets are presented net to the extent that there are netting arrangements or similar agreements with the counterparties. The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Company Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Liabilities from risk management activities $ 12 $ 198 $ 123 $ 121 Other deferred charges and assets/Other deferred credits and liabilities 31 117 52 44 Total derivatives designated as hedging instruments for regulatory purposes 43 315 175 165 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities — 29 3 27 Other deferred charges and assets/Other deferred credits and liabilities 3 4 6 4 Interest rate derivatives: Assets from risk management activities/Liabilities from risk management activities — 74 12 62 Other deferred charges and assets/Other deferred credits and liabilities — 190 — 240 Foreign currency derivatives: Assets from risk management activities/Liabilities from risk management activities — 34 — 34 Other deferred charges and assets/Other deferred credits and liabilities — 88 — 182 Total derivatives designated as hedging instruments in cash flow and fair value hedges 3 419 21 549 Energy-related derivatives not designated as hedging instruments Assets from risk management activities/Liabilities from risk management activities 8 8 13 13 Other deferred charges and assets/Other deferred credits and liabilities 1 2 2 1 Total derivatives not designated as hedging instruments 9 10 15 14 Gross amounts recognized 55 744 211 728 Gross amounts offset (a) (23) (85) (70) (111) Net amounts recognized in the Balance Sheets (b) $ 32 $ 659 $ 141 $ 617 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Alabama Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 6 $ 69 $ 42 $ 21 Other deferred charges and assets/Other deferred credits and liabilities 9 41 20 18 Total derivatives designated as hedging instruments for regulatory purposes 15 110 62 39 Gross amounts offset (10) (10) (24) (24) Net amounts recognized in the Balance Sheets $ 5 $ 100 $ 38 $ 15 Georgia Power Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 2 $ 82 $ 36 $ 43 Other deferred charges and assets/Other deferred credits and liabilities 10 42 6 18 Total derivatives designated as hedging instruments for regulatory purposes 12 124 42 61 Energy-related derivatives not designated as hedging instruments Other deferred charges and assets/Other deferred credits and liabilities 1 — — 1 Gross amounts recognized 13 124 42 62 Gross amounts offset (11) (11) (21) (21) Net amounts recognized in the Balance Sheets $ 2 $ 113 $ 21 $ 41 Mississippi Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 3 $ 27 $ 33 $ 24 Other deferred charges and assets/Other deferred credits and liabilities 12 34 26 8 Total derivatives designated as hedging instruments for regulatory purposes 15 61 59 32 Gross amounts offset (14) (14) (17) (17) Net amounts recognized in the Balance Sheets $ 1 $ 47 $ 42 $ 15 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ — $ 5 $ — $ 12 Other deferred charges and assets/Other deferred credits and liabilities 3 — 5 — Foreign currency derivatives: Other current assets/Other current liabilities — 11 — 11 Other deferred charges and assets/Other deferred credits and liabilities — 11 — 36 Total derivatives designated as hedging instruments in cash flow and fair value hedges 3 27 5 59 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities — — 2 — Other deferred charges and assets/Other deferred credits and liabilities — — 1 — Total derivatives not designated as hedging instruments — — 3 — Net amounts recognized in the Balance Sheets $ 3 $ 27 $ 8 $ 59 Southern Company Gas Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 1 $ 20 $ 12 $ 33 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities — 24 3 15 Other deferred charges and assets/Other deferred credits and liabilities — 4 1 4 Interest rate derivatives: Other current assets/Other current liabilities — 20 — 14 Other deferred charges and assets/Other deferred credits and liabilities — 59 — 72 Total derivatives designated as hedging instruments in cash flow and fair value hedges — 107 4 105 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 7 8 11 12 Other deferred charges and assets/Other deferred credits and liabilities 1 2 1 1 Total derivatives not designated as hedging instruments 8 10 12 13 Gross amounts recognized 9 137 28 151 Gross amounts offset (a) 12 (50) — (41) Net amounts recognized in the Balance Sheets (b) $ 21 $ 87 $ 28 $ 110 (a) Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $62 million and $41 million at December 31, 2023 and 2022, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented. (c) Energy-related derivatives not designated as hedging instruments were immaterial at December 31, 2022. There were no such instruments at December 31, 2023. At December 31, 2023 and 2022, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows: Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At December 31, 2023: Energy-related derivatives: Other regulatory assets, current $ (180) $ (67) $ (80) $ (25) $ (8) Other regulatory assets, deferred (87) (32) (33) (22) — Other regulatory liabilities, current 9 4 — 1 4 Other regulatory liabilities, deferred 1 — 1 — — Total energy-related derivative gains (losses) $ (257) $ (95) $ (112) $ (46) $ (4) At December 31, 2022: Energy-related derivatives: Other regulatory assets, current $ (71) $ (8) $ (26) $ (13) $ (24) Other regulatory assets, deferred (23) (7) (14) (2) — Other regulatory liabilities, current 72 29 19 22 2 Other regulatory liabilities, deferred 31 9 2 20 — Total energy-related derivative gains (losses) $ 9 $ 23 $ (19) $ 27 $ (22) For the years ended December 31, 2023, 2022, and 2021, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows: Gain (Loss) From Derivatives Recognized in OCI 2023 2022 2021 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ (81) $ 3 $ 34 Interest rate derivatives (12) 46 5 Foreign currency derivatives 14 (105) (103) Fair value hedges () : Foreign currency derivatives 21 (24) (3) Total $ (58) $ (80) $ (67) Georgia Power Cash flow hedges: Interest rate derivatives $ (2) $ 31 $ — Southern Power Cash flow hedges: Energy-related derivatives $ (18) $ (15) $ 12 Foreign currency derivatives 14 (105) (103) Total $ (4) $ (120) $ (91) Southern Company Gas Cash flow hedges: Energy-related derivatives $ (63) $ 18 $ 22 () Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. The pre-tax effects of interest rate derivatives designated as cash flow hedging instruments on AOCI were immaterial for Alabama Power for all years presented and immaterial for Mississippi Power in 2023. The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2023, 2022, and 2021 were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships 2023 2022 2021 (in millions) Southern Company Total cost of natural gas $ 1,644 $ 3,004 $ 1,619 Gain (loss) on energy-related cash flow hedges (a) (44) 37 17 Total other operations and maintenance 6,093 6,573 5,902 Gain (loss) on energy-related cash flow hedges (a) (2) — — Total depreciation and amortization 4,525 3,663 3,565 Gain (loss) on energy-related cash flow hedges (a) (23) (5) 9 Total interest expense, net of amounts capitalized (2,446) (2,022) (1,837) Gain (loss) on interest rate cash flow hedges (a) (35) (25) (27) Gain (loss) on foreign currency cash flow hedges (a) (11) (19) (24) Gain (loss) on interest rate fair value hedges (b) 37 (291) (30) Total other income (expense), net 553 500 449 Gain (loss) on foreign currency cash flow hedges (a)(c) 19 (83) (104) Gain (loss) on foreign currency fair value hedges 69 (106) (63) Amount excluded from effectiveness testing recognized in earnings (21) 24 3 Southern Power Total depreciation and amortization $ 504 $ 516 $ 517 Gain (loss) on energy-related cash flow hedges (a) (23) (5) 9 Total interest expense, net of amounts capitalized (129) (138) (147) Gain (loss) on foreign currency cash flow hedges (a) (11) (19) (24) Total other income (expense), net 12 7 10 Gain (loss) on foreign currency cash flow hedges (a)(c) 19 (83) (104) Southern Company Gas Total cost of natural gas $ 1,644 $ 3,004 $ 1,619 Gain (loss) on energy-related cash flow hedges (a) (44) 37 17 Total other operations and maintenance 1,194 1,176 1,072 Gain (loss) on energy-related cash flow hedges (a) (2) — — Total interest expense, net of amounts capitalized (310) (263) (238) Gain (loss) on interest rate cash flow hedges (a) (19) (4) — Gain (loss) on interest rate fair value hedges (b) 6 (86) — (a) Reclassified from AOCI into earnings. (b) For fair value hedges, changes in the fair value of the derivative contracts are generally equal to changes in the fair value of the underlying debt and have no material impact on income. (c) The reclassification from AOCI into other income (expense), net completely offsets currency gains and losses arising from changes in the U.S. currency exchange rates used to record the euro-denominated notes. The pre-tax effects of cash flow hedge accounting on income for interest rate derivatives were immaterial for the traditional electric operating companies for all years presented. At December 31, 2023 and 2022, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At December 31, 2023 At December 31, 2022 At December 31, 2023 At December 31, 2022 (in millions) (in millions) Southern Company Long-term debt $ (3,024) $ (2,927) $ 235 $ 282 Southern Company Gas Long-term debt $ (427) $ (415) $ 70 $ 81 The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2023, 2022, and 2021 were as follows: Gain (Loss) Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2023 2022 2021 (in millions) Energy-related derivatives Natural gas revenues () $ — $ (11) $ (117) Cost of natural gas 59 (65) (27) Total derivatives in non-designated hedging relationships $ 59 $ (76) $ (144) (*) Excludes the impact of weather derivatives recorded in natural gas revenues of $15 million and $(7) million for 2023 and 2022, respectively, as they are accounted for based on intrinsic value rather than fair value. There was no weather derivatives impact for 2021. The pre-tax effects of energy-related derivatives not designated as hedging instruments were immaterial for all other Registrants for all years presented. Contingent Features The Registrants do not have any credit arrangements that would require material changes in payment schedules or terminations as a result of a credit rating downgrade. There are certain derivatives that could require collateral, but not accelerated payment, in the event of various credit rating changes of certain Southern Company subsidiaries. Generally, collateral may be provided by a Southern Company guaranty, letter of credit, or cash. At December 31, 2023, the Registrants had no collateral posted with derivative counterparties to satisfy these arrangements. For Southern Company, the fair value of foreign currency derivative liabilities and interest rate derivative liabilities with contingent features, and the maximum potential collateral requirements arising from the credit-risk-related contingent features at a rating below BBB- and/or Baa3, was $52 million at December 31, 2023. For Southern Power, the fair value of foreign currency derivative liabilities with contingent features, and the maximum potential collateral requirements arising from the credit-risk-related contingent features at a rating below BBB- and/or Baa3, was immaterial at December 31, 2023. For the traditional electric operating companies and Southern Power, energy-related derivative liabilities with contingent features and the maximum potential collateral requirements arising from the credit-risk-related contingent features, at a rating below BBB- and/or Baa3, were immaterial a t December 31, 2023. The maximum potential collateral requirements arising from the credit-risk-related contingent features for the traditional electric operating companies and Southern Power include certain agreements that could require collateral in the event that one or more Southern Company power pool participants has a credit rating change to below investment grade. Alabama Power and Southern Power maintain accounts with certain regional transmission organizations to facilitate financial derivative transactions and they may be required to post collateral based on the value of the positions in these accounts and the associated margin requirements. At December 31, 2023, cash collateral posted in these accounts was immaterial for Alabama Power and Southern Power. Southern Company Gas maintains accounts with brokers or the clearing houses of certain exchanges to facilitate financial derivative transactions. Based on the value of the positions in these accounts and the associated margin requirements, Southern Company Gas may be required to deposit cash into these accounts. At December 31, 2023, cash collateral held on deposit in broker margin accounts was $62 million. The Registrants are exposed to losses related to financial instruments in the event of counterparties' nonperformance. The Registrants only enter into agreements and material transactions with counterparties that have investment grade credit ratings by Moody's and S&P or with counterparties who have posted collateral to cover potential credit exposure. The Registrants have also established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk. Southern Company Gas uses established credit policies to determine and monitor the creditworthiness of counterparties, including requirements to post collateral or other credit security, as well as the quality of pledged collateral. Collateral or credit security is most often in the form of cash or letters of credit from an investment-grade financial institution, but may also include cash or U.S. government securities held by a trustee. Prior to entering a physical transaction, Southern Company Gas assigns its counterparties an internal credit rating and credit limit based on the counterparties' Moody's, S&P, and Fitch ratings, commercially available credit reports, and audited financial statements. Southern Company Gas may require counterparties to pledge additional collateral when deemed necessary. Southern Company Gas utilizes netting agreements whenever possible to mitigate exposure to counterparty credit risk. Netting agreements enable Southern Company Gas to net certain assets and liabilities by counterparty across product lines and against cash collateral, provided the netting and cash collateral agreements include such provisions. While the amounts due from, or owed to, counterparties are settled net, they are recorded on a gross basis on the balance sheet as energy marketing receivables and energy marketing payables. The Registrants do not anticipate a material adverse effect on their respective financial statements as a result of counterparty nonperformance.

ACQUISITIONS AND DISPOSITIONS

ACQUISITIONS AND DISPOSITIONS	12 Months Ended
ACQUISITIONS AND DISPOSITIONS	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
ACQUISITIONS AND DISPOSITIONS	ACQUISITIONS AND DISPOSITIONS None of the dispositions discussed herein, both individually and combined, represented a strategic shift in operations for the applicable Registrants that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales have been classified as discontinued operations for any of the periods presented. Southern Power Southern Power's acquisition-related costs for the projects discussed under "Asset Acquisitions" and "Construction Projects" were not material for any of the years presented. There were no asset acquisitions during 2022. Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern Expected/Actual COD PPA Asset Acquisitions During 2023 Millers Branch (a) Solar EDF Renewables Development, Inc. 200 Haskell County, TX 100% Fourth quarter 2025 20 years South Cheyenne Solar Hanwha Q Cells USA Corp. 150 Laramie County, WY 100% Second quarter 2024 20 years Asset Acquisitions During 2021 Deuel Harvest (b) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years (a) The project includes an option to expand capacity up to an additional 300 MWs. Subsequent to December 31, 2023, Southern Power committed to expand the construction of the facility through a second phase adding up to 205 MWs, with commercial operation expected to occur in the second quarter 2026. (b) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest. The aggregate purchase price for the two projects acquired during 2023 was $193 million, which is primarily recorded within construction work in progress on the balance sheet at December 31, 2023. Construction Projects Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years (a) In 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. See Note 9 under "Lessor" for additional information. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility. Development Projects Southern Power purchased wind turbine equipment in 2016 and 2017 for deployment to development and construction projects. All of this equipment has either been deployed to projects that have been completed or has been sold to third parties. Gains on wind turbine equipment contributed to various equity method investments totaled approximately $37 million in 2021. Southern Company Gas Sale of Sequent In July 2021, Southern Company Gas affiliates completed the sale of Sequent to Williams Field Services Group for a total cash purchase price of $159 million, including final working capital adjustments. The pre-tax gain associated with th e transaction was approximately $121 million ($92 million after tax). The sale resulted in $85 million of additional tax expense. Sale of Natural Gas Storage Facilities In September 2022, certain affiliates of Southern Company Gas entered into agreements to sell two natural gas storage facilities located in California and Texas for an aggregate purchase price of $186 million, plus working capital and certain other adjustments. The sale of the Texas facility was completed in November 2022 and the sale of the California facility was completed on September 22, 2023. Both sales resulted in an immaterial loss. Completion of the sale of the Texas facility was subject to release of a Southern Company Gas parent guarantee, which was executed in October 2022 and, as a result, Southern Company Gas recorded pre-tax impairment charges totaling approximately $131 million ($99 million after tax) in the fourth quarter 2022.
ACQUISITIONS AND DISPOSITIONS	ACQUISITIONS AND DISPOSITIONS None of the dispositions discussed herein, both individually and combined, represented a strategic shift in operations for the applicable Registrants that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales have been classified as discontinued operations for any of the periods presented. Southern Company In October 2021, Southern Company completed the sale of a leveraged lease investment to the lessee for $45 million. No gain or loss was recognized on the sale; however, it did result in the recognition of approximately $16 million of additional tax benefits. Prior to the sale, in the second quarter 2021, a charge of $7 million ($6 million after tax) was recorded to reduce the investment to its estimated fair value, less costs to sell. In December 2021, Southern Company completed the termination of its leasehold interest in assets associated with its two international leveraged lease projects and received cash proceeds of approximately $673 million after the accelerated exercise of the lessee's purchase options. The pre-tax gain associated with the transaction was approximately $93 million ($99 million gain after tax). Alabama Power In September 2022, Alabama Power completed its acquisition of the Calhoun Generating Station, which was accounted for as an asset acquisition. The total purchase price was $179 million, of which $171 million was related to net assets recorded within property, plant, and equipment on the balance sheet and reflected in property additions within the investing section of the statement of cash flows. The remainder primarily related to fossil fuel stock and materials and supplies. See Note 2 under "Alabama Power – Rate CNP New Plant" for additional information. Southern Power Southern Power's acquisition-related costs for the projects discussed under "Asset Acquisitions" and "Construction Projects" were not material for any of the years presented. There were no asset acquisitions during 2022. Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern Expected/Actual COD PPA Asset Acquisitions During 2023 Millers Branch (a) Solar EDF Renewables Development, Inc. 200 Haskell County, TX 100% Fourth quarter 2025 20 years South Cheyenne Solar Hanwha Q Cells USA Corp. 150 Laramie County, WY 100% Second quarter 2024 20 years Asset Acquisitions During 2021 Deuel Harvest (b) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years (a) The project includes an option to expand capacity up to an additional 300 MWs. Subsequent to December 31, 2023, Southern Power committed to expand the construction of the facility through a second phase adding up to 205 MWs, with commercial operation expected to occur in the second quarter 2026. (b) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest. The aggregate purchase price for the two projects acquired during 2023 was $193 million, which is primarily recorded within construction work in progress on the balance sheet at December 31, 2023. Construction Projects Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years (a) In 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. See Note 9 under "Lessor" for additional information. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility. Development Projects Southern Power purchased wind turbine equipment in 2016 and 2017 for deployment to development and construction projects. All of this equipment has either been deployed to projects that have been completed or has been sold to third parties. Gains on wind turbine equipment contributed to various equity method investments totaled approximately $37 million in 2021. Southern Company Gas Sale of Sequent In July 2021, Southern Company Gas affiliates completed the sale of Sequent to Williams Field Services Group for a total cash purchase price of $159 million, including final working capital adjustments. The pre-tax gain associated with th e transaction was approximately $121 million ($92 million after tax). The sale resulted in $85 million of additional tax expense. Sale of Natural Gas Storage Facilities In September 2022, certain affiliates of Southern Company Gas entered into agreements to sell two natural gas storage facilities located in California and Texas for an aggregate purchase price of $186 million, plus working capital and certain other adjustments. The sale of the Texas facility was completed in November 2022 and the sale of the California facility was completed on September 22, 2023. Both sales resulted in an immaterial loss. Completion of the sale of the Texas facility was subject to release of a Southern Company Gas parent guarantee, which was executed in October 2022 and, as a result, Southern Company Gas recorded pre-tax impairment charges totaling approximately $131 million ($99 million after tax) in the fourth quarter 2022.

SEGMENT AND RELATED INFORMATION

SEGMENT AND RELATED INFORMATION	12 Months Ended
SEGMENT AND RELATED INFORMATION	Dec. 31, 2023
Segment Reporting [Abstract]
SEGMENT AND RELATED INFORMATION	SEGMENT AND RELATED INFORMATION Southern Company Southern Company's reportable business segments are the sale of electricity by the traditional electric operating companies, the sale of electricity in the competitive wholesale market by Southern Power, and the sale of natural gas and other complementary products and services by Southern Company Gas. Revenues from sales by Southern Power to the traditional electric operating companies were $537 million, $875 million, and $515 million in 2023, 2022, and 2021, respectively. Revenues from sales of natural gas from Southern Company Gas to the traditional electric operating companies were immaterial for all periods presented. Revenues from sales of natural gas from Southern Company Gas (prior to its sale of Sequent) to Southern Power were $18 million in 2021. The "All Other" column includes the Southern Company parent entity, which does not allocate operating expenses to business segments. Also, this category includes segments below the quantitative threshold for separate disclosure. These segments include providing distributed energy and resilience solutions and deploying microgrids for commercial, industrial, governmental, and utility customers, as well as investments in telecommunications. All other inter-segment revenues are not material. Financial data for business segments and products and services for the years ended December 31, 2023, 2022, and 2021 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) 2023 Operating revenues $ 18,358 $ 2,189 $ (549) $ 19,998 $ 4,702 $ 718 $ (165) $ 25,253 Depreciation and amortization 3,361 504 — 3,865 582 78 — 4,525 Interest income 69 7 — 76 9 26 (26) 85 Earnings from equity method investments (1) — — (1) 140 5 — 144 Interest expense 1,145 129 — 1,274 310 879 (17) 2,446 Income taxes (benefit) 571 12 — 583 211 (298) — 496 Segment net income (loss) (a)(b)(c)(d) 3,637 357 — 3,994 615 (635) 2 3,976 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 100,429 12,761 (545) 112,645 25,083 2,446 (843) 139,331 2022 Operating revenues $ 20,408 $ 3,369 $ (904) $ 22,873 $ 5,962 $ 593 $ (149) $ 29,279 Depreciation and amortization 2,513 516 — 3,029 559 75 — 3,663 Interest income 44 3 — 47 3 16 (7) 59 Earnings from equity method investments — — — — 148 3 — 151 Interest expense 929 138 — 1,067 263 694 (2) 2,022 Income taxes (benefit) 828 20 — 848 180 (233) — 795 Segment net income (loss) (a)(b)(e)(f) 3,318 354 — 3,672 572 (711) (9) 3,524 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 95,861 13,081 (659) 108,283 24,621 2,665 (678) 134,891 2021 Operating revenues $ 16,614 $ 2,216 $ (530) $ 18,300 $ 4,380 $ 582 $ (149) $ 23,113 Depreciation and amortization 2,436 517 — 2,953 536 76 — 3,565 Interest income 20 1 — 21 — 4 (3) 22 Earnings from equity method investments 1 — — 1 50 24 1 76 Interest expense 821 147 — 968 238 631 — 1,837 Income taxes (benefit) 232 (13) — 219 275 (227) — 267 Segment net income (loss) (a)(b)(g)(h)(i) 1,981 266 — 2,247 539 (384) (9) 2,393 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes pre-tax charges (credits) to income at Georgia Power for the estimated probable loss associated with the construction of Plant Vogtle Units 3 and 4 of $(68) million ($(50) million after tax) in 2023, $183 million ($137 million after tax) in 2022, and $1.7 billion ($1.3 billion after tax) in 2021. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (c) For Southern Power, includes an $18 million pre-tax loss recovery ($9 million after tax and partnership allocations) related to an arbitration award and a $16 million pre-tax gain ($12 million after tax) on the sale of spare parts. See Note 3 under "General Litigation Matters – Southern Power" for additional information. (d) For Southern Company Gas, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information. (e) For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (f) For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets" for additional information. (g) For Southern Power, includes gains on wind turbine equipment contributed to various equity method investments totaling approximately $37 million pre-tax ($28 million after tax). See Notes 7 and 15 under "Southern Power" for additional information. (h) For Southern Company Gas, includes a pre-tax gain of $121 million ($92 million after tax) related to its sale of Sequent, as well as the resulting $85 million of additional tax expense due to changes in state apportionment rates, and pre-tax impairment charges totaling $84 million ($67 million after tax) related to its equity method investment in the PennEast Pipeline project. See Notes 7 and 15 under "Southern Company Gas" for additional information. (i) For the "All Other" column, includes a pre-tax gain of $93 million ($99 million gain after tax) associated with the termination of two leveraged leases projects. See Note 15 under "Southern Company" for additional information. Products and Services Electric Utilities' Revenues Year Retail Wholesale Other Total (in millions) 2023 $ 16,343 $ 2,467 $ 1,188 $ 19,998 2022 18,197 3,641 1,035 22,873 2021 14,852 2,455 993 18,300 Southern Company Gas' Revenues Year Gas Gas All Other Total (in millions) 2023 $ 4,090 $ 548 $ 64 $ 4,702 2022 5,240 638 84 5,962 2021 3,656 475 249 4,380 Southern Company Gas Southern Company Gas manages its business through three reportable segments – gas distribution operations, gas pipeline investments, and gas marketing services. Prior to the sale of Sequent on July 1, 2021, Southern Company Gas' reportable segments also included wholesale gas services. The non-reportable segments are combined and presented as all other. See Note 15 under "Southern Company Gas" for additional information on the disposition activities described herein. Gas distribution operations is the largest component of Southern Company Gas' business and includes natural gas local distribution utilities that construct, manage, and maintain intrastate natural gas pipelines and gas distribution facilities in four states. Gas pipeline investments consists of joint ventures in natural gas pipeline investments including a 50% interest in SNG and a 50% joint ownership interest in the Dalton Pipeline. These natural gas pipelines enable the provision of diverse sources of natural gas supplies to the customers of Southern Company Gas. See Notes 5 and 7 for additional information. Through July 1, 2021, wholesale gas services provided natural gas asset management and/or related logistics services for each of Southern Company Gas' utilities except Nicor Gas as well as for non-affiliated companies. Additionally, wholesale gas services engaged in natural gas storage and gas pipeline arbitrage and related activities. Gas marketing services provides natural gas marketing to end-use customers primarily in Georgia and Illinois through SouthStar. The all other column includes segments and subsidiaries that fall below the quantitative threshold for separate disclosure, including storage and fuels operations. The all other column included a natural gas storage facility in Texas through its sale in November 2022 and a natural gas storage facility in California through its sale in September 2023. Financial data for business segments for the years ended December 31, 2023, 2022, and 2021 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (a) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) 2023 Operating revenues $ 4,105 $ 32 $ — $ 548 $ 4,685 $ 36 $ (19) $ 4,702 Depreciation and amortization 561 5 — 15 581 1 — 582 Operating income (loss) 804 22 — 130 956 (4) (13) 939 Earnings from equity method investments — 140 — — 140 — — 140 Interest expense 275 32 3 310 — — 310 Income taxes 126 32 — 37 195 16 — 211 Segment net income (loss) (b) 441 98 — 91 630 (15) — 615 Total assets 22,906 1,534 — 1,615 26,055 9,675 (10,647) 25,083 2022 Operating revenues $ 5,267 $ 32 $ — $ 638 $ 5,937 $ 55 $ (30) $ 5,962 Depreciation and amortization 516 5 — 16 537 22 — 559 Operating income (loss) 803 21 — 133 957 (135) (8) 814 Earnings from equity method investments — 148 — — 148 — — 148 Interest expense 229 27 — 3 259 4 — 263 Income taxes (benefit) 145 35 — 37 217 (37) — 180 Segment net income (loss) (c) 470 107 — 94 671 (99) — 572 Total assets 22,040 1,577 — 1,616 25,233 8,943 (9,555) 24,621 2021 Operating revenues $ 3,679 $ 32 $ 188 $ 475 $ 4,374 $ 38 $ (32) $ 4,380 Depreciation and amortization 482 5 — 18 505 31 — 536 Operating income (loss) 708 21 241 125 1,095 (40) — 1,055 Earnings from equity method investments — 50 — — 50 — — 50 Interest expense 207 25 2 3 237 1 — 238 Income taxes 120 27 32 34 213 62 — 275 Segment net income (loss) (d)(e)(f) 412 19 107 88 626 (87) — 539 Total assets 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 (a) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment in 2023 or 2022. Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188 (b) For gas distribution operations, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information. (c) For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (d) For gas pipeline investments, includes pre-tax impairment charges totaling $84 million ($67 million after tax) related to the equity method investment in the PennEast Pipeline project. See Note 7 under "Southern Company Gas" for additional information. (e) For wholesale gas services, includes a pre-tax gain of $121 million ($92 million after tax) related to the sale of Sequent. (f) For the "All Other" column, includes $85 million of additional tax expense as a result of the sale of Sequent.

VALUATION AND QUALIFYING ACCOUN

VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
VALUATION AND QUALIFYING ACCOUNTS	Dec. 31, 2023
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
VALUATION AND QUALIFYING ACCOUNTS	SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2023, 2022, AND 2021 Additions Description Balance at Beginning of Period Charged to Income Charged to Other Accounts Deductions (a) Balance at End of Period (in millions) Provision for uncollectible accounts: Southern Company (b) 2023 $ 71 $ 87 $ 3 $ 93 $ 68 2022 78 71 (1) 77 71 2021 118 51 (23) 68 78 Alabama Power 2023 $ 14 $ 16 $ — $ 14 $ 16 2022 14 10 — 10 14 2021 43 (7) — 22 14 Georgia Power (b) 2023 $ 3 $ 26 $ — $ 25 $ 4 2022 2 21 — 20 3 2021 26 16 (23) 17 2 Mississippi Power 2023 $ 1 $ 2 $ — $ 2 $ 1 2022 1 1 1 2 1 2021 1 1 — 1 1 Southern Power 2023 $ 1 $ — $ — $ — $ 1 2022 5 (2) — 2 1 2021 — 5 — — 5 Southern Company Gas 2023 $ 50 $ 43 $ 3 $ 52 $ 44 2022 39 55 — 44 50 2021 40 26 — 27 39 (a) Deductions represent write-offs of accounts considered to be uncollectible, less recoveries of amounts previously written off. (b) During 2020, Georgia Power recorded $23 million of expected bad debt related to the COVID-19 pandemic to a regulatory asset in accordance with orders from the Georgia PSC. During 2021, based on a review of bad debt amounts under a Georgia PSC-approved methodology, Georgia Power reversed substantially all of the amount recorded in 2020. SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS (CONTINUED) FOR THE YEARS ENDED DECEMBER 31, 2023, 2022, AND 2021 Additions Description Balance at Beginning of Period Charged to Income Charged to Other Accounts Deductions Balance at End of Period (in millions) Tax valuation allowance (net state): Southern Company (a)(b) 2023 $ 207 $ (14) $ (25) $ — $ 168 2022 169 68 (30) — 207 2021 112 57 — — 169 Georgia Power (a) 2023 $ 98 $ (15) $ (23) $ — $ 60 2022 58 70 (30) — 98 2021 28 30 — — 58 Mississippi Power (b) 2023 $ 32 $ — $ — $ — $ 32 2022 32 — — — 32 2021 32 — — — 32 Southern Power (b) 2023 $ 21 $ — $ — $ — $ 21 2022 21 — — — 21 2021 27 (6) — — 21 Southern Company Gas (b) 2023 $ 7 $ — $ (2) $ — $ 5 2022 7 — — — 7 2021 4 3 — — 7 (a) In 2018, Georgia Power established a valuation allowance for certain Georgia state tax credits expected to expire prior to being fully utilized, which has been adjusted in subsequent years as a result of changes in projected state taxable income. (b) Associated with a state net operating loss carryforward expected to expire prior to being fully utilized. See Note 10 to the financial statements in Item 8 herein for additional information.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Dec. 31, 2023
Accounting Policies [Abstract]
General	General Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. Prior to the sale of Sequent on July 1, 2021, these businesses also included wholesale gas services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plant Hatch and Plant Vogtle Units 1 through 3, and is currently managing construction and start-up of Plant Vogtle Unit 4. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers. See Note 15 for information regarding the sale of Sequent. The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in a HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information. The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies. The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04) providing temporary guidance to ease the potential burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which began phasing out on December 31, 2021. The discontinuation date of the overnight 1-, 3-, 6-, and 12-month tenors of LIBOR was June 30, 2023, which was beyond the original effective date of ASU 2020-04; therefore, in December 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 (ASU 2022-06) to defer the sunset date of ASU 2020-04 from December 31, 2022 to December 31, 2024. The amendments were elective and applied to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The guidance (i) simplified accounting analyses under current GAAP for contract modifications; (ii) simplified the assessment of hedge effectiveness and allows hedging relationships affected by reference rate reform to continue; and (iii) allowed a one-time election to sell or transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform. An entity could elect to apply the amendments prospectively from March 12, 2020 through December 31, 2024 by accounting topic. The Registrants elected to apply the amendments to modifications of debt and derivative arrangements that meet the scope of ASU 2020-04 and ASU 2022-06. Certain provisions in PPAs at Southern Power included references to LIBOR. Contract amendments have been executed to change to a SOFR-based interest rate. Southern Power adopted and applied the practical expedients guidance to these PPAs. Additionally, the Registrants referenced LIBOR for certain debt and hedging arrangements. As of July 1, 2023, all of the debt and hedging arrangements of the Registrants had transitioned to a SOFR-based interest rate based on the terms of the agreements. There were no material impacts from the transition to SOFR and no impacts to any existing accounting conclusions. See Note 14 under "Interest Rate Derivatives" for additional information.
Affiliate Transactions	Affiliate Transactions
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process. In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the traditional electric operating company or the natural gas distribution utility would be required to determine if any impairment to other assets, including plant, exists and write down the assets, if impaired, to their fair values. All regulatory assets and liabilities are to be reflected in rates. See Note 2 for additional information including details of regulatory assets and liabilities reflected in the balance sheets for Southern Company, the traditional electric operating companies, and Southern Company Gas.
Revenues	Revenues The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information. Traditional Electric Operating Companies The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are accrued at the end of each fiscal period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies. Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer. For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation. Southern Power Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, normal sale derivatives, or contracts with customers. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease. Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer. Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation. When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements. Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information. Southern Company Gas Gas Distribution Operations Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities. Atlanta Gas Light operates in a deregulated natural gas market wher eby M arketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Company Gas recognizes revenue as the performance obligations are satisfied over time as natural gas is delivered to the customer. The performance obligations related to wholesale gas services are satisfied, and revenue is recognized, at a point in time when natural gas is delivered to the customer. Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage. Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period. The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $20 million, $(5) million, and $11 million in 2023, 2022, and 2021, respectively. These programs are as follows: • Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas; • Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and • Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year. Wholesale Gas Services Prior to the sale of Sequent on July 1, 2021, Southern Company Gas netted revenues from energy and risk management activities with the associated costs. Profits from sales between segments were eliminated and recognized as goods or services sold to end-use customers. Southern Company Gas recorded wholesale gas services' transactions that qualified as derivatives at fair value with changes in fair value recognized in earnings in the period of change and characterized as unrealized gains or losses. Gains and losses on derivatives held for energy trading purposes were presented on a net basis in revenue. See Note 15 under "Southern Company Gas" for additional information on the sale of Sequent. Gas Marketing Services Southern Company Gas recognizes revenues from natural gas sales and transportation services in the same period in which the related volumes are delivered to customers and recognizes sales revenues from residential and certain commercial and industrial customers on the basis of scheduled meter readings. Southern Company Gas also recognizes unbilled revenues for estimated deliveries of gas not yet billed to these customers from the most recent meter reading date to the end of the accounting period. For other commercial and industrial customers and for all wholesale customers, revenues are based on actual deliveries during the period. Southern Company Gas recognizes revenues on 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts. Concentration of Revenue Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer comprises 10% or more of each company's revenues. Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs, which are subject to regulation by the FERC. The contracts with these wholesale customers represented 14.0% of Mississippi Power's total operating revenues in 2023.
Fuel Costs	Fuel Costs Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs.
Cost of Natural Gas	Cost of Natural Gas Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively. Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas and gains and losses associated with certain derivatives.
Income Taxes and Other Taxes	Income Taxes The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production. Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2023 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Current and Deferred Income Taxes – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information. In June 2023, the IRS issued temporary regulations related to the transferability of certain tax credits under the IRA. Southern Company and certain subsidiaries have tax credits that are eligible to be transferred. The discount recorded on transferred credits is booked through income tax expense. Under current tax law, Georgia Power is eligible to generate advanced nuclear PTCs for Plant Vogtle Unit 3, which are recognized as an income tax benefit based on KWH production and are eligible to be transferred. Pursuant to the Global Amendments to the Vogtle Joint Ownership Agreements (as defined in Note 2 under "Georgia Power – Nuclear Construction – Joint Owner Contracts"), Georgia Power is purchasing advanced nuclear PTCs for Plant Vogtle Unit 3 from the other Vogtle Owners. The gain recognized on the purchase of the joint owner PTCs is recognized as an income tax benefit. The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information. Other Taxes Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer. Southern Company Gas is taxed on its gas revenues by various governmental authorities, but is allowed to recover these taxes from its customers. Revenue taxes imposed on the natural gas distribution utilities are recorded at the amount charged to customers, which may include a small administrative fee, as operating revenues, and the related taxes imposed on Southern Company Gas are recorded as operating expenses on the statements of income. Revenue taxes included in operating expenses were $129 million, $158 million, and $119 million in 2023, 2022, and 2021, respectively.
Allowance for Funds Used During Construction and Interest Capitalized	Allowance for Funds Used During Construction and Interest Capitalized The traditional electric operating companies and the natural gas distribution utilities record AFUDC, which represents the estimated debt and equity costs of capital funds that are necessary to finance the construction of new regulated facilities. While cash is not realized currently, AFUDC increases the revenue requirement and is recovered over the service life of the asset through a higher rate base and higher depreciation. The equity component of AFUDC is not taxable. Interest related to financing the construction of new facilities at Southern Power and new facilities not included in the traditional electric operating companies' and Southern Company Gas' regulated rates is capitalized in accordance with standard interest capitalization requirements.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets Southern Power's intangible assets consist primarily of certain PPAs acquired, which are amortized over the term of the respective PPA. Southern Company Gas' goodwill and other intangible assets primarily relate to its 2016 acquisition by Southern Company. In addition to these items, Southern Company's goodwill and other intangible assets also relate to its 2016 acquisition of PowerSecure. For its 2023 and 2022 annual impairment tests, Southern Company Gas management performed the qualitative assessment and determined that it was more likely than not that the fair value of all of its reporting units with goodwill exceeded their carrying amounts, and therefore no quantitative assessment was required. For its 2021 annual impairment test, Southern Company Gas management performed the quantitative assessment and confirmed that the fair values of all of its reporting units with goodwill exceeded their carrying amounts. For its 2023 and 2021 annual impairment tests, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure exceeding its carrying amount. For its 2022 annual impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure being lower than its carrying amount. The fair value was estimated using a discounted cash flow analysis. The decline in fair value primarily resulted from declining macroeconomic conditions, reducing sales growth and estimated cash flows. As a result, a goodwill impairment of $119 million was recorded in the fourth quarter 2022.
Acquisition Accounting	Acquisition Accounting At the time of an acquisition, management will assess whether acquired assets and activities meet the definition of a business. Acquisitions that meet the definition of a business are accounted for under the acquisition method, and operating results from the date of acquisition are included in the acquiring entity's financial statements. Identifiable assets acquired, liabilities assumed, and any noncontrolling interests (including any intangible assets) are recognized and measured at fair value. Assets acquired that do not meet the definition of a business are accounted for as an asset acquisition. The purchase price of each asset acquisition is allocated based on the relative fair value of assets acquired. Determining the fair value of assets acquired and liabilities assumed requires management judgment and management may engage independent valuation experts to assist in this process. Fair values are determined by using market participant assumptions and typically include the timing and amounts of future cash flows, incurred construction costs, the nature of acquired contracts, discount rates, power market prices, and expected asset lives. For potential or successful acquisitions that meet the definition of a business, any due diligence or transaction costs incurred are expensed as incurred. If the acquisition is an asset acquisition, direct and incremental transaction costs can be capitalized as a component of the cost of the assets acquired.
Development Costs	Development Costs For Southern Power, development costs are capitalized once a project is probable of completion, primarily based on a review of its economics and operational feasibility, as well as the status of power off-take agreements and regulatory approvals, if applicable. Southern Power's capitalized development costs are included in CWIP on the balance sheets. All of Southern Power's development costs incurred prior to the determination that a project is probable of completion are expensed as incurred and included in other operations and maintenance expense in the statements of income. If it is determined that a project is no longer probable of completion, any of Southern Power's capitalized development costs are expensed and included in other operations and maintenance expense in the statements of income.
Long-Term Service Agreements	Long-Term Service Agreements The traditional electric operating companies and Southern Power have entered into LTSAs for the purpose of securing maintenance support for certain of their generating facilities. The LTSAs cover all planned inspections on the covered equipment, which generally includes the cost of all labor and materials. The LTSAs also obligate the counterparties to cover the costs of unplanned maintenance on the covered equipment subject to limits and scope specified in each contract. Payments made under the LTSAs for the performance of any planned inspections or unplanned capital maintenance are recorded in the statements of cash flows as investing activities. Receipts of major parts into materials and supplies inventory prior to planned inspections are treated as noncash transactions in the statements of cash flows. Any payments made prior to the work being performed are recorded as prepayments in other current assets and noncurrent assets on the balance sheets. At the time work is performed, an appropriate amount is accrued for future payments or transferred from the prepayment and recorded as property, plant, and equipment or expensed.
Transmission Receivables/Prepayments	Transmission Receivables/Prepayments As a result of Southern Power's acquisition and construction of generating facilities, Southern Power has transmission receivables and/or prepayments representing the portion of interconnection network and transmission upgrades that will be reimbursed to Southern Power. Upon completion of the related project, transmission costs are generally reimbursed by the interconnection provider within a five-year period and the receivable/prepayments are reduced as payments or services are received.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash For purposes of the financial statements, temporary cash investments are considered cash equivalents. Temporary cash investments are securities with original maturities of 90 days or less.
Storm Damage and Reliability Reserves	Storm Damage and Reliability Reserves In accordance with their respective state PSC orders, the traditional electric operating companies accrue certain amounts annually related to storm damage recovery. Each traditional electric operating company maintains a reserve to cover or is allowed to defer and recover the cost of damages from major storms to its transmission and distribution lines and, for Mississippi Power, the cost of uninsured damages to its generation facilities and other property. Alabama Power also has authority from the Alabama PSC to accrue certain additional amounts as circumstances warrant. Alabama Power recorded an additional accrual of $65 million in 2021.
Materials and Supplies	Materials and Supplies Materials and supplies for the traditional electric operating companies generally includes the average cost of transmission, distribution, and generating plant materials. Materials and supplies for Southern Company Gas generally includes propane gas inventory, liquefied natural gas inventory, fleet fuel, and other materials and supplies. Materials and supplies for Southern Power generally includes the average cost of generating plant materials. Materials are recorded to inventory when purchased and then expensed or capitalized to property, plant, and equipment, as appropriate, at weighted average cost when installed. In addition, certain major parts are recorded as inventory when acquired and then capitalized at cost when installed to property, plant, and equipment.
Fuel Inventory	Fuel Inventory Fuel inventory for the traditional electric operating companies includes the average cost of coal, natural gas, oil, transportation, and emissions allowances. Fuel inventory for Southern Power, which is included in other current assets, includes the average cost of oil, natural gas, and emissions allowances. Fuel is recorded to inventory when purchased and then expensed, at weighted average cost, as used. Emissions allowances granted by the EPA are included in inventory at zero cost. The traditional electric operating companies recover fuel expense through fuel cost recovery rates approved by each state PSC or, for wholesale rates, the FERC.
Natural Gas for Sale	Natural Gas for Sale With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a weighted average cost of gas basis. In Georgia's deregulated, competitive environment, Marketers sell natural gas to firm end-use customers at market-based prices. On a monthly basis, Atlanta Gas Light assigns to Marketers the majority of the pipeline storage services that it has under contract, along with a corresponding amount of inventory. Atlanta Gas Light retains and manages a portion of its pipeline storage assets and related natural gas inventories for system balancing and to serve system demand. Nicor Gas' natural gas inventory is carried at cost on a LIFO basis. Inventory decrements occurring during the year that are restored prior to year-end are charged to cost of natural gas at the estimated annual replacement cost. Inventory decrements that are not restored prior to year-end are charged to cost of natural gas at the actual LIFO cost of the inventory layers liquidated. The cost of natural gas, including inventory costs, is recovered from customers under a purchased gas recovery mechanism adjusted for differences between actual costs and amounts billed; therefore, LIFO liquidations have no impact on Southern Company's or Southern Company Gas' net income. At December 31, 2023, the Nicor Gas LIFO inventory balance w as $186 million. Based on the average cost of gas purchased in December 2023, the estimated replacement cost of Nicor Gas' inventory at December 31, 2023 was $268 million.
Provision for Uncollectible Accounts	Provision for Uncollectible Accounts The customers of the traditional electric operating companies and the natural gas distribution utilities are billed monthly. For the majority of receivables, a provision for uncollectible accounts is established based on historical collection experience and other factors. For the remaining receivables, if the company is aware of a specific customer's inability to pay, a provision for uncollectible accounts is recorded to reduce the receivable balance to the amount reasonably expected to be collected. If circumstances change, the estimate of the recoverability of accounts receivable could change as well. Circumstances that could affect this estimate include, but are not limited to, customer credit issues, customer deposits, and general economic conditions. Customers' accounts are written off once they are deemed to be uncollectible. For all periods presented, uncollectible accounts averaged less than 1% of revenues for each Registrant. Credit risk exposure at Nicor Gas is mitigated by a bad debt rider approved by the Illinois Commission. The bad debt rider provides for the recovery from (or refund to) customers of the difference between Nicor Gas' actual bad debt experience on an annual basis and the benchmark bad debt expense used to establish its base rates for the respective year.
Concentration of Credit Risk	Concentration of Credit Risk Concentration of credit risk occurs at Atlanta Gas Light for amounts billed for services and other costs to its customers, which consist of 13 Marketers in Georgia (including SouthStar). The credit risk exposure to the Marketers varies seasonally, with the lowest exposure in the non-peak summer months and the highest exposure in the peak winter months. Marketers are responsible for the retail sale of natural gas to end-use customers in Georgia. The functions of the retail sale of gas include the purchase and sale of natural gas, customer service, billings, and collections. The provisions of Atlanta Gas Light's tariff allow Atlanta Gas Light to obtain credit security support in an amount equal to a minimum of two times a Marketer's highest month's estimated bill from Atlanta Gas Light.
Financial Instruments	Financial Instruments The traditional electric operating companies and Southern Power use derivative financial instruments to limit exposure to fluctuations in interest rates, the prices of certain fuel purchases, electricity purchases and sales, and occasionally foreign currency exchange rates. Southern Company Gas uses derivative financial instruments to limit exposure to fluctuations in natural gas prices, weather, interest rates, and commodity prices. All derivative financial instruments are recognized as either assets or liabilities on the balance sheets (included in "Other" or shown separately as "Risk Management Activities") and are measured at fair value. See Note 13 for additional information regarding fair value. Substantially all of the traditional electric operating companies' and Southern Power's bulk energy purchases and sales contracts that meet the definition of a derivative are excluded from fair value accounting requirements because they qualify for the "normal" scope exception, and are accounted for under the accrual method. Derivative contracts that qualify as cash flow hedges of anticipated transactions or are recoverable through the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs result in the deferral of related gains and losses in AOCI or regulatory assets and liabilities, respectively, until the hedged transactions occur. Other derivative contracts that qualify as fair value hedges are marked to market through current period income and are recorded on a net basis in the statements of income. Cash flows from derivatives are classified on the statements of cash flows in the same category as the hedged item. See Note 14 for additional information regarding derivatives. The Registrants offset fair value amounts recognized for multiple derivative instruments executed with the same counterparty under netting arrangements. The Registrants had no outstanding collateral repayment obligations or rights to reclaim collateral arising from derivative instruments recognized at December 31, 2023. The Registrants are exposed to potential losses related to financial instruments in the event of counterparties' nonperformance. The Registrants have established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk. Southern Company Gas Southern Company Gas enters into weather derivative contracts as economic hedges of natural gas revenues in the event of warmer-than-normal weather in the Heating Season. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are also reflected in natural gas revenues in the statements of income. Southern Company Gas enters into transactions to secure transportation capacity between delivery points in order to serve its customers and various markets. NYMEX futures and OTC contracts are used to capture the price differential or spread between the locations served by the capacity to substantially protect the natural gas revenues that will ultimately be realized when the physical flow of natural gas between delivery points occurs. These contracts generally meet the definition of derivatives and are carried at fair value on the balance sheets, with changes in fair value included in earnings in the period of change. These contracts are not designated as hedges for accounting purposes. The purchase, transportation, storage, and sale of natural gas are accounted for on a weighted average cost or accrual basis, as appropriate, rather than on the fair value basis utilized for the derivatives used to mitigate the natural gas price risk associated with the storage and transportation portfolio. Monthly demand charges are incurred for the contracted storage and transportation capacity and payments associated with asset management agreements, and these demand charges and payments are recognized on the statements of income in the period they are incurred. This difference in accounting methods can result in volatility in reported earnings, even though the economic margin is substantially unchanged from the dates the transactions were consummated. The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. For the traditional electric operating companies, Southern Power, and Southern Company Gas' other businesses, each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information. See Note 15 under "Southern Company Gas" for additional information regarding the sale of Sequent. Energy-Related Derivatives The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations. Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in operating revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in operating revenues. Energy-related derivative contracts are accounted for under one of three methods: • Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism. • Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions. • Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered. Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Foreign Currency Derivatives Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI.
Comprehensive Income	Comprehensive Income The objective of comprehensive income is to report a measure of all changes in common stock equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners. Comprehensive income consists of net income attributable to the Registrant, changes in the fair value of qualifying cash flow hedges, and reclassifications for amounts included in net income. Comprehensive income also consists of certain changes in pension and other postretirement benefit plans for Southern Company, Southern Power, and Southern Company Gas.
Variable Interest Entities	Variable Interest Entities The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. The primary beneficiary of a VIE is required to consolidate the VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. See Note 7 for additional information regarding VIEs.
Asset Retirement Obligations	AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets. The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally ash ponds. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle Units 1 through 3). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease. The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO. Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs.
Nuclear Decommissioning	Nuclear Decommissioning The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers, neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities. Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis.
Fair Value Measurement	Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement. • Level 1 consists of observable market data in an active market for identical assets or liabilities. • Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable. • Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information. In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported. Valuation Methodologies The energy-related derivatives primarily consist of exchange-traded and over-the-counter financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard over-the-counter products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used. For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available. The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information. Southern Power has contingent payment obligations related to two of its acquisitions whereby it is primarily obligated to make generation-based payments to the seller, commencing at the commercial operation of each facility and continuing through 2026 and 2035, respectively. The obligations are primarily categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility's generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of contingent consideration reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial. Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments. "Other investments" primarily includes investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of costs for affiliate transactions	Costs for these services from SCS in 2023, 2022, and 2021 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2023 $ 611 $ 857 $ 113 $ 86 $ 261 2022 549 762 115 86 262 2021 504 663 120 89 239 Mississippi Southern (in millions) 2023 $ 4 $ 13 2022 4 29 2021 9 15 Alabama Georgia Southern Southern Company Gas (in millions) 2023 $ 12 $ 101 $ 34 $ 28 2022 18 99 37 27 2021 14 108 31 29 2023 2022 2021 Alabama Power 4.1 % 2.7 % 2.7 % Georgia Power 3.8 % 3.3 % 3.3 % Mississippi Power 3.4 % 3.4 % 3.6 % Southern Company Gas 2.7 % 2.7 % 2.8 %
Schedule of total AFUDC and interest capitalized	Total AFUDC and interest capitalized for the applicable Registrants in 2023, 2022, and 2021 was as follows: Southern Company Alabama Georgia () Southern Southern Company Gas (in millions) 2023 $ 400 $ 109 $ 251 $ 3 $ 37 2022 327 90 213 — 24 2021 282 68 190 6 18 () See Note 2 under "Georgia Power – Nuclear Construction" for information on the inclusion of a portion of construction costs related to Plant Vogtle Unit 4 in Georgia Power's rate base.
Schedule of average AFUDC composite rates	The average AFUDC composite rates for 2023, 2022, and 2021 for the traditional electric operating companies and the natural gas distribution utilities were as follows: 2023 2022 2021 Alabama Power 8.1 % 7.9 % 7.9 % Georgia Power (a) 7.6 % 7.3 % 7.2 % Mississippi Power (b) — % 5.3 % 2.5 % Southern Company Gas: Atlanta Gas Light 7.4 % 7.6 % 7.7 % Chattanooga Gas 7.1 % 7.1 % 7.1 % Nicor Gas 4.6 % 2.0 % 0.1 % (a) Excludes AFUDC related to the construction of Plant Vogtle Units 3 and 4. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (b) Mississippi Power's AFUDC was immaterial in 2023.
Schedule of goodwill balances	At December 31, 2023 and 2022, goodwill was as follows: At December 31, 2023 At December 31, 2022 (in millions) Southern Company $ 5,161 $ 5,161 Southern Company Gas: Gas distribution operations $ 4,034 $ 4,034 Gas marketing services 981 981 Southern Company Gas total $ 5,015 $ 5,015
Schedule of intangible assets subject to amortization	At December 31, 2023 and 2022, other intangible assets were as follows: At December 31, 2023 At December 31, 2022 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Subject to amortization: Customer relationships $ 212 $ (172) $ 40 $ 212 $ (162) $ 50 Trade names 64 (53) 11 64 (44) 20 PPA fair value adjustments 390 (148) 242 390 (129) 261 Other 3 (3) — 5 (5) — Total subject to amortization $ 669 $ (376) $ 293 $ 671 $ (340) $ 331 Not subject to amortization: FCC licenses 75 — 75 75 — 75 Total other intangible assets $ 744 $ (376) $ 368 $ 746 $ (340) $ 406 Southern Power () PPA fair value adjustments $ 390 $ (148) $ 242 $ 390 $ (129) $ 261 Southern Company Gas () Gas marketing services Customer relationships $ 156 $ (145) $ 11 $ 156 $ (139) $ 17 Trade names 26 (21) 5 26 (17) 9 Total other intangible assets $ 182 $ (166) $ 16 $ 182 $ (156) $ 26 (*) All subject to amortization.
Schedule of intangible assets not subject to amortization	At December 31, 2023 and 2022, other intangible assets were as follows: At December 31, 2023 At December 31, 2022 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Subject to amortization: Customer relationships $ 212 $ (172) $ 40 $ 212 $ (162) $ 50 Trade names 64 (53) 11 64 (44) 20 PPA fair value adjustments 390 (148) 242 390 (129) 261 Other 3 (3) — 5 (5) — Total subject to amortization $ 669 $ (376) $ 293 $ 671 $ (340) $ 331 Not subject to amortization: FCC licenses 75 — 75 75 — 75 Total other intangible assets $ 744 $ (376) $ 368 $ 746 $ (340) $ 406 Southern Power () PPA fair value adjustments $ 390 $ (148) $ 242 $ 390 $ (129) $ 261 Southern Company Gas () Gas marketing services Customer relationships $ 156 $ (145) $ 11 $ 156 $ (139) $ 17 Trade names 26 (21) 5 26 (17) 9 Total other intangible assets $ 182 $ (166) $ 16 $ 182 $ (156) $ 26 (*) All subject to amortization.
Schedule of amortization associated with other intangible assets	Amortization associated with other intangible assets in 2023, 2022, and 2021 was as follows: 2023 2022 2021 (in millions) Southern Company (a) $ 38 $ 39 $ 44 Southern Power (b) 20 20 20 Southern Company Gas: Gas marketing services 10 11 15 (a) Includes $20 million annually recorded as a reduction to operating revenues. (b) Recorded as a reduction to operating revenues.
Schedule of estimated future amortization of other intangible assets	At December 31, 2023, the estimated amortization associated with other intangible assets for the next five years is as follows: 2024 2025 2026 2027 2028 (in millions) Southern Company $ 35 $ 32 $ 27 $ 24 $ 24 Southern Power 20 20 20 20 20 Southern Company Gas 7 6 3 — —
Schedule of cash, cash equivalents, and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants: Southern Alabama Power Georgia Southern Southern (in millions) At December 31, 2023 Cash and cash equivalents $ 748 $ 324 $ 9 $ 124 $ 33 Restricted cash (a) : Other current assets 141 85 37 17 2 Other deferred charges and assets 31 — 29 3 — Total cash, cash equivalents, and restricted cash (b) $ 921 $ 409 $ 75 $ 144 $ 35 At December 31, 2022 Cash and cash equivalents $ 1,917 $ 687 $ 364 $ 131 $ 81 Restricted cash (a) : Other current assets 62 — 60 — 2 Other deferred charges and assets 58 — 56 3 — Total cash, cash equivalents, and restricted cash (b) $ 2,037 $ 687 $ 480 $ 133 $ 83 (a) For Alabama Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2023 . For Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2022. See Note 8 under "Long-term Debt" for additional information. For Southern Power, reflects $17 million at December 31, 2023 resulting from an arbitration award held to fund future replacement costs and $3 million at both December 31, 2023 and 2022 held to fund estimated construction completion costs at the Deuel Harvest wind facility. See Note 3 under "General Litigation Matters – Southern Power" and Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.
Reconciliation of restricted cash and cash equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants: Southern Alabama Power Georgia Southern Southern (in millions) At December 31, 2023 Cash and cash equivalents $ 748 $ 324 $ 9 $ 124 $ 33 Restricted cash (a) : Other current assets 141 85 37 17 2 Other deferred charges and assets 31 — 29 3 — Total cash, cash equivalents, and restricted cash (b) $ 921 $ 409 $ 75 $ 144 $ 35 At December 31, 2022 Cash and cash equivalents $ 1,917 $ 687 $ 364 $ 131 $ 81 Restricted cash (a) : Other current assets 62 — 60 — 2 Other deferred charges and assets 58 — 56 3 — Total cash, cash equivalents, and restricted cash (b) $ 2,037 $ 687 $ 480 $ 133 $ 83 (a) For Alabama Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2023 . For Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds in 2022. See Note 8 under "Long-term Debt" for additional information. For Southern Power, reflects $17 million at December 31, 2023 resulting from an arbitration award held to fund future replacement costs and $3 million at both December 31, 2023 and 2022 held to fund estimated construction completion costs at the Deuel Harvest wind facility. See Note 3 under "General Litigation Matters – Southern Power" and Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.
Schedule of storm damage reserves	Storm damage reserve activity for the traditional electric operating companies during 2023 was as follows: Southern Company Alabama Power Georgia Power Mississippi (in millions) Balance at December 31, 2022 $ 216 $ 97 $ 83 $ 36 Accrual 61 18 31 12 Weather-related damages (211) (39) (168) (4) Balance at December 31, 2023 $ 66 $ 76 $ (54) $ 44 The traditional electric operating companies accrued the following amounts related to storm damage recovery in 2022 and 2021: Southern Company (a)(b) Alabama (a) Georgia Mississippi Power (b) (in millions) 2022 $ 239 $ 19 $ 213 $ 7 2021 286 75 213 (2) (a) Alabama Power's 2021 amount includes the $65 million additional accrual discussed above. (b) Mississippi Power's net accrual includes carrying costs, as well as amortization of related excess deferred income tax benefits. Southern Alabama Mississippi (in millions) 2023 $ 63 $ 52 $ 11 2022 191 166 25
Schedule of AOCI (loss) balances, net of tax effects	AOCI (loss) balances, net of tax effects, for Southern Company, Southern Power, and Southern Company Gas were as follows: Qualifying Pension and Other Accumulated Other Comprehensive Income (Loss) () (in millions) Southern Company Balance at December 31, 2022 $ (149) $ (18) $ (167) Current period change 28 (38) (10) Balance at December 31, 2023 $ (121) $ (56) $ (177) Southern Power Balance at December 31, 2022 $ (9) $ (9) $ (18) Current period change 8 (7) 1 Balance at December 31, 2023 $ (1) $ (16) $ (17) Southern Company Gas Balance at December 31, 2022 $ (25) $ 56 $ 31 Current period change 1 (16) (15) Balance at December 31, 2023 $ (24) $ 40 $ 16 () May not add due to rounding.

REGULATORY MATTERS (Tables)

REGULATORY MATTERS (Tables)	12 Months Ended
REGULATORY MATTERS (Tables)	Dec. 31, 2023
Regulated Operations [Abstract]
Schedule of regulatory assets	Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2023 and 2022 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2023 AROs (a)(w) $ 5,733 $ 1,936 $ 3,505 $ 247 $ — Retiree benefit plans (b)(w) 3,011 815 976 140 146 Remaining net book value of retired assets (c) 1,357 499 841 17 — Deferred income tax charges (d) 897 262 605 28 — Under recovered regulatory clause revenues (e) 413 381 — 12 20 Fuel-hedging (realized and unrealized) losses (f) 270 100 121 49 — Deferred depreciation (g) 270 143 127 — — Environmental remediation (h)(w) 255 — 20 — 235 Loss on reacquired debt (i) 238 35 197 5 1 Vacation pay (j)(w) 217 83 107 11 16 Software and cloud computing costs (k) 150 59 84 2 5 Regulatory clauses (l) 140 112 — — 28 Storm damage (m) 92 — 54 38 — Nuclear outage (n) 83 50 33 — — Long-term debt fair value adjustment (o) 60 — — — 60 Qualifying repairs of natural gas distribution systems (p) 40 — — — 40 Plant Daniel Units 3 and 4 (q) 25 — — 25 — Kemper County energy facility assets, net (r) 7 — — 7 — Other regulatory assets (s) 182 39 33 18 93 Deferred income tax credits (d) (4,686) (1,506) (2,161) (241) (759) Other cost of removal obligations (a) (1,312) 28 617 (186) (1,771) Over recovered regulatory clause revenues (e) (287) (3) (46) — (238) Reliability reserves (t) (179) (143) — (36) — Storm/property damage reserves (t) (120) (76) — (44) — Customer refunds (u) (19) (15) (4) — — Fuel-hedging (realized and unrealized) gains (f) (6) (5) (1) — Other regulatory liabilities (v) (308) (74) (18) (2) (101) Total regulatory assets (liabilities), net $ 6,523 $ 2,720 $ 5,090 $ 90 $ (2,225) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(w) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(w) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (e) 953 788 — 31 134 Deferred income tax charges (d) 866 250 583 30 — Environmental remediation (h)(w) 294 — 25 — 269 Loss on reacquired debt (i) 257 38 213 5 1 Vacation pay (j)(w) 212 82 108 10 12 Regulatory clauses (l) 142 142 — — — Software and cloud computing costs (k) 111 46 59 — 6 Nuclear outage (n) 82 52 30 — — Long-term debt fair value adjustment (o) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (f) 60 15 45 — — Storm damage (m) 44 — — 44 — Plant Daniel Units 3 and 4 (q) 27 — — 27 — Qualifying repairs of natural gas distribution systems (p) 26 — — — 26 Kemper County energy facility assets, net (r) 20 — — 20 — Other regulatory assets (s) 171 36 27 16 92 Deferred income tax credits (d) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (t) (216) (97) (83) (36) — Reliability reserves (t) (191) (166) — (25) — Customer refunds (u) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (f) (83) (38) (21) (24) — Over recovered regulatory clause revenues (e) (64) — (38) — (26) Other regulatory liabilities (v) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power and Mississippi Power and up to 14 years for Georgia Power and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Unit 10 ($451 million at December 31, 2023) being amortized over 14 years (through 2037) and Plant Barry Unit 4 ($39 million at December 31, 2023) being amortized over 11 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2, Plant Hammond Units 1 through 4, and Plant Branch Unit 4 (totaling $488 million, $339 million, and $8 million, respectively, at December 31, 2023) are being amortized over remaining periods between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Deferred income tax charges are recovered and deferred income tax credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2023 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2024 and/or 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts include $145 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 to be recovered over a 10-year period beginning the month after Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. Mississippi Power : Related amounts include retail deferred income tax liabilities ($11 million at December 31, 2023) that are expected to be fully amortized through 2024. Southern Company Gas : Related amounts include deferred income tax liabilities ($1 million at December 31, 2023) being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (e) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to seven years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2023, $12 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (f) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (g) Alabama Power : Represents deferred depreciation expense for Plant Barry Unit 5 ($57 million at December 31, 2023) and Plant Barry common coal assets ($24 million at December 31, 2023) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($62 million at December 31, 2023) to be amortized until 2039 beginning when the assets are retired. Georgia Power : Represents deferred depreciation expense for Plant Scherer Units 1 through 3 ($70 million at December 31, 2023) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($40 million at December 31, 2023) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($17 million at December 31, 2023) to be amortized over a 10-year period beginning the month after Plant Vogtle Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. (h) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (i) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2023, the remaining amortization periods do not exceed 24 years for Alabama Power, 29 years for Georgia Power, 18 years for Mississippi Power, and four years for Southern Company Gas. (j) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (k) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027) and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). (l) Alabama Power : Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. Southern Company Gas : Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years. (m) See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over a seven-year period through 2029. (n) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (o) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 15 years at December 31, 2023. (p) Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years. (q) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2023, consists of the $17 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized through 2035. (r) At December 31, 2023, includes $9 million of regulatory assets (wholesale) expected to be fully amortized by 2035 and $2 million of regulatory liabilities (retail) expected to be fully amortized by 2024. (s) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 20 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 15 years for Southern Company Gas. (t) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (u) Primarily includes approximately $15 million and $62 million at December 31, 2023 and 2022, respectively, for Alabama Power and $119 million at December 31, 2022 for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (v) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 11 years for Alabama Power, nine years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas. (w) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability. The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily comprised of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025. December 31, 2023 December 31, 2022 (in millions) Atlanta Gas Light $ 23 $ 35 Virginia Natural Gas 10 10 Chattanooga Gas 7 2 Nicor Gas 3 3 Total $ 43 $ 50
Schedule of regulatory liabilities	Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2023 and 2022 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2023 AROs (a)(w) $ 5,733 $ 1,936 $ 3,505 $ 247 $ — Retiree benefit plans (b)(w) 3,011 815 976 140 146 Remaining net book value of retired assets (c) 1,357 499 841 17 — Deferred income tax charges (d) 897 262 605 28 — Under recovered regulatory clause revenues (e) 413 381 — 12 20 Fuel-hedging (realized and unrealized) losses (f) 270 100 121 49 — Deferred depreciation (g) 270 143 127 — — Environmental remediation (h)(w) 255 — 20 — 235 Loss on reacquired debt (i) 238 35 197 5 1 Vacation pay (j)(w) 217 83 107 11 16 Software and cloud computing costs (k) 150 59 84 2 5 Regulatory clauses (l) 140 112 — — 28 Storm damage (m) 92 — 54 38 — Nuclear outage (n) 83 50 33 — — Long-term debt fair value adjustment (o) 60 — — — 60 Qualifying repairs of natural gas distribution systems (p) 40 — — — 40 Plant Daniel Units 3 and 4 (q) 25 — — 25 — Kemper County energy facility assets, net (r) 7 — — 7 — Other regulatory assets (s) 182 39 33 18 93 Deferred income tax credits (d) (4,686) (1,506) (2,161) (241) (759) Other cost of removal obligations (a) (1,312) 28 617 (186) (1,771) Over recovered regulatory clause revenues (e) (287) (3) (46) — (238) Reliability reserves (t) (179) (143) — (36) — Storm/property damage reserves (t) (120) (76) — (44) — Customer refunds (u) (19) (15) (4) — — Fuel-hedging (realized and unrealized) gains (f) (6) (5) (1) — Other regulatory liabilities (v) (308) (74) (18) (2) (101) Total regulatory assets (liabilities), net $ 6,523 $ 2,720 $ 5,090 $ 90 $ (2,225) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(w) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(w) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (e) 953 788 — 31 134 Deferred income tax charges (d) 866 250 583 30 — Environmental remediation (h)(w) 294 — 25 — 269 Loss on reacquired debt (i) 257 38 213 5 1 Vacation pay (j)(w) 212 82 108 10 12 Regulatory clauses (l) 142 142 — — — Software and cloud computing costs (k) 111 46 59 — 6 Nuclear outage (n) 82 52 30 — — Long-term debt fair value adjustment (o) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (f) 60 15 45 — — Storm damage (m) 44 — — 44 — Plant Daniel Units 3 and 4 (q) 27 — — 27 — Qualifying repairs of natural gas distribution systems (p) 26 — — — 26 Kemper County energy facility assets, net (r) 20 — — 20 — Other regulatory assets (s) 171 36 27 16 92 Deferred income tax credits (d) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (t) (216) (97) (83) (36) — Reliability reserves (t) (191) (166) — (25) — Customer refunds (u) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (f) (83) (38) (21) (24) — Over recovered regulatory clause revenues (e) (64) — (38) — (26) Other regulatory liabilities (v) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power and Mississippi Power and up to 14 years for Georgia Power and Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Unit 10 ($451 million at December 31, 2023) being amortized over 14 years (through 2037) and Plant Barry Unit 4 ($39 million at December 31, 2023) being amortized over 11 years (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2, Plant Hammond Units 1 through 4, and Plant Branch Unit 4 (totaling $488 million, $339 million, and $8 million, respectively, at December 31, 2023) are being amortized over remaining periods between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Deferred income tax charges are recovered and deferred income tax credits are primarily amortized over the related property lives, which may range up to 64 years for Alabama Power, 56 years for Georgia Power, 55 years for Mississippi Power, and 85 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2023 include excess federal deferred income tax liabilities that are available for the benefit of customers in 2024 and/or 2025, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts include $145 million of deferred income tax assets related to construction costs for Plant Vogtle Units 3 and 4 to be recovered over a 10-year period beginning the month after Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. Mississippi Power : Related amounts include retail deferred income tax liabilities ($11 million at December 31, 2023) that are expected to be fully amortized through 2024. Southern Company Gas : Related amounts include deferred income tax liabilities ($1 million at December 31, 2023) being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (e) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to seven years, with the majority expected to be recovered within one year. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2023, $12 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (f) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (g) Alabama Power : Represents deferred depreciation expense for Plant Barry Unit 5 ($57 million at December 31, 2023) and Plant Barry common coal assets ($24 million at December 31, 2023) to be amortized until 2036 beginning when Plant Barry Unit 5 is retired and Plant Gaston Unit 5 coal assets ($62 million at December 31, 2023) to be amortized until 2039 beginning when the assets are retired. Georgia Power : Represents deferred depreciation expense for Plant Scherer Units 1 through 3 ($70 million at December 31, 2023) to be amortized over six years beginning in 2029 and Plant Bowen Units 1 and 2 ($40 million at December 31, 2023) to be amortized over four years beginning in 2031, both as approved under Georgia Power's 2022 ARP, and Plant Vogtle Unit 3 and common facilities ($17 million at December 31, 2023) to be amortized over a 10-year period beginning the month after Plant Vogtle Unit 4 achieves commercial operation. See "Georgia Power – Nuclear Construction – Regulatory Matters" herein for additional information on recovery of costs related to Plant Vogtle Units 3 and 4. (h) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (i) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2023, the remaining amortization periods do not exceed 24 years for Alabama Power, 29 years for Georgia Power, 18 years for Mississippi Power, and four years for Southern Company Gas. (j) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (k) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 are being amortized over five years (through 2027) and the recovery period for costs incurred after 2022 will be determined in its next base rate case. For Mississippi Power, the recovery period will be determined in Mississippi Power's annual PEP filing process. For Southern Company Gas, costs are being amortized ratably over the life of the related software, which ranges up to 10 years (through 2034). (l) Alabama Power : Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. Southern Company Gas : Represents amounts related to Nicor Gas' volume balancing adjustment rider expected to be recovered over a period of less than two years. (m) See "Georgia Power – Storm Damage Recovery" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over a seven-year period through 2029. (n) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (o) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 15 years at December 31, 2023. (p) Represents deferred costs of certain repairs at Atlanta Gas Light being amortized over 20 years. (q) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2023, consists of the $17 million retail portion being amortized through 2039 over the remaining life of the related property and the $8 million wholesale portion being amortized through 2035. (r) At December 31, 2023, includes $9 million of regulatory assets (wholesale) expected to be fully amortized by 2035 and $2 million of regulatory liabilities (retail) expected to be fully amortized by 2024. (s) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 20 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 15 years for Southern Company Gas. (t) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (u) Primarily includes approximately $15 million and $62 million at December 31, 2023 and 2022, respectively, for Alabama Power and $119 million at December 31, 2022 for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (v) Comprised of numerous immaterial components with remaining amortization periods at December 31, 2023 generally not exceeding 11 years for Alabama Power, nine years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas. (w) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Public utilities general disclosures	Details of tariff adjustments are provided in the following table: Tariff 2023 2024 (in millions) Traditional base $ 194 $ 275 ECCR (21) (99) DSM 37 10 MFF 6 5 Total $ 216 $ 191 The Georgia PSC approved the following tariff adjustments under the 2019 ARP effective January 1 2022: Tariff 2022 (in millions) Traditional base $ 192 ECCR (12) DSM (25) MFF 2 Total $ 157 The following table provides regulatory information for Southern Company Gas' natural gas distribution utilities: Nicor Gas Atlanta Gas Light Virginia Natural Gas Chattanooga Gas Authorized ROE at December 31, 2023 9.51% 10.25% 9.70% 9.80% Weather normalization mechanisms (a) ü ü Decoupled, including straight-fixed-variable rates (b) ü ü ü Regulatory infrastructure program rate (c) ü ü ü ü Bad debt rider (d) ü ü ü Energy efficiency plan (e) ü ü Annual base rate adjustment mechanism (f) ü ü Year of last base rate case decision 2023 2019 2023 2018 (a) Designed to help stabilize operating results by allowing recovery of costs in the event of unseasonal weather, but are not direct offsets to the potential impacts on earnings of weather and customer consumption. (b) Allows for recovery of fixed customer service costs separately from assumed natural gas volumes used by customers and provides a benchmark level of revenue for recovery. (c) See "Infrastructure Replacement Programs and Capital Projects" herein for additional information. Chattanooga Gas' pipeline replacement program costs are recovered through its annual base rate review mechanism. (d) The recovery (refund) of bad debt expense over (under) an established benchmark expense. The gas portion of bad debt expense is recovered through purchased gas adjustment mechanisms. Nicor Gas also has a rider to recover the non-gas portion of bad debt expense. (e) Recovery of costs associated with plans to achieve specified energy savings goals. (f) Regulatory mechanism allowing annual adjustments to base rates up or down based on authorized ROE and/or ROE range. The following table and discussions provide updates on the infrastructure replacement programs and capital projects at the natural gas distribution utilities at December 31, 2023. These programs are risk-based and designed to update and replace cast iron, bare steel, and mid-vintage plastic materials or expand Southern Company Gas' distribution systems to improve reliability and meet operational flexibility and growth. Utility Program Recovery Capital Expenditures in 2023 Capital Expenditures Since Project Inception Pipe Scope of Program Duration Last (in millions) (miles) (miles) (years) Nicor Gas Investing in Illinois Qualifying Infrastructure Plant () Rider $ 365 $ 3,228 1,367 1,367 9 2023 Virginia Natural Gas SAVE Rider 75 486 567 695 13 2024 Atlanta Gas Light System Reinforcement Rider Rider 104 180 20 N/A 3 2024 Chattanooga Gas Pipeline Replacement Program Rate Base 9 16 15 73 7 2027 Total $ 553 $ 3,910 1,969 2,135 () Included replacement of pipes, compressors, and transmission mains along with other improvements such as new meters. This program ended November 30, 2023 with all expenditures placed in service. Recovery of program costs is described under "Nicor Gas" herein. The following table provides a summary of QIP capital investments during the nine-year program: Year Status of QIP Annual Review Proceeding Capital Investments Disallowed Month of Disallowance (in millions) 2015 – 2018 Complete $ 1,246 $ — 2019 Complete (a) 415 32 June 2023 2020 Filed March 2021 402 (b) 2021 Filed March 2022 392 (b) 2022 Filed March 2023 408 (b) 6 (a)(c) November 2023 2023 To be filed by March 20, 2024 365 (b) 25 (a)(c) November 2023 $ 3,228 $ 63 (a) Appealed to the Illinois Appellate Court. (b) Capital investments are subject to the required QIP annual review proceeding; years 2020 through 2022 are pending with the Illinois Commission. (c) Disallowed in Nicor Gas' 2023 general base rate case proceeding. See "Rate Proceedings – Nicor Gas" herein for additional information regarding the Illinois Commission's disallowance of certain capital investments.
Schedule of revised cost and schedule	Georgia Power's approximate proportionate share of the remaining estimated capital cost to complete Plant Vogtle Units 3 and 4, including contingency, through the second quarter 2024 is as follows: (in millions) Base project capital cost forecast (a)(b) $ 10,717 Construction contingency estimate 36 Total project capital cost forecast (a)(b) 10,753 Net investment at December 31, 2023 (b) (10,564) Remaining estimate to complete $ 189 (a) Includes approximately $610 million of costs that are not shared with the other Vogtle Owners, including $33 million of construction monitoring costs, and approximately $567 million of incremental costs under the cost-sharing provisions of the joint ownership agreements described below. Excludes financing costs expected to be capitalized through AFUDC of approximately $440 million, of which $417 million had been accrued through December 31, 2023. (b) Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.

CONTINGENCIES, COMMITMENTS, A_2

CONTINGENCIES, COMMITMENTS, AND GUARANTEES (Tables)	12 Months Ended
CONTINGENCIES, COMMITMENTS, AND GUARANTEES (Tables)	Dec. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Schedule of regulatory assets and liabilities	At December 31, 2023 and 2022, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power and Mississippi Power did not have environmental remediation liabilities at December 31, 2023 or 2022. Southern Company Georgia Southern Company Gas (in millions) December 31, 2023: Environmental remediation liability: Other current liabilities $ 44 $ 14 $ 30 Accrued environmental remediation 192 — 192 Under recovered environmental remediation costs: Other regulatory assets, current $ 45 $ 5 $ 40 Other regulatory assets, deferred 210 15 195 December 31, 2022: Environmental remediation liability: Other current liabilities $ 65 $ 15 $ 49 Accrued environmental remediation 207 — 207 Under recovered environmental remediation costs: Other regulatory assets, current $ 59 $ 5 $ 54 Other regulatory assets, deferred 235 20 215
Expected future contractual obligations	Southern Company Gas' expected future contractual obligations for pipeline charges, storage capacity, and gas supply that are not recognized on the balance sheets at December 31, 2023 were as follows: Pipeline Charges, Storage Capacity, and Gas Supply (in millions) 2024 $ 587 2025 432 2026 231 2027 148 2028 103 Thereafter 785 Total $ 2,286

REVENUE FROM CONTRACTS WITH C_2

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	12 Months Ended
REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Disaggregation of revenue	The following table disaggregates revenue from contracts with customers for the periods presented: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Operating revenues Retail electric revenues Residential $ 7,309 $ 2,904 $ 4,105 $ 300 $ — $ — Commercial 5,860 1,928 3,624 308 — — Industrial 3,613 1,721 1,558 334 — — Other 112 12 91 9 — — Total retail electric revenues 16,894 6,565 9,378 951 — — Natural gas distribution revenues Residential 1,981 — — — — 1,981 Commercial 505 — — — — 505 Transportation 1,184 — — — — 1,184 Industrial 45 — — — — 45 Other 324 — — — — 324 Total natural gas distribution revenues 4,039 — — — — 4,039 Wholesale electric revenues PPA energy revenues 1,107 234 87 20 790 — PPA capacity revenues 624 156 51 45 376 — Non-PPA revenues 250 65 35 407 409 — Total wholesale electric revenues 1,981 455 173 472 1,575 — Other natural gas revenues Gas marketing services 528 — — — — 528 Other natural gas revenues 31 — — — — 31 Total natural gas revenues 559 — — — — 559 Other revenues 1,355 213 578 39 55 — Total revenue from contracts with customers 24,828 7,233 10,129 1,462 1,630 4,598 Other revenue sources (a) 425 (183) (11) 12 559 104 Total operating revenues $ 25,253 $ 7,050 $ 10,118 $ 1,474 $ 2,189 $ 4,702 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Operating revenues Retail electric revenues Residential $ 6,604 $ 2,638 $ 3,664 $ 302 $ — $ — Commercial 5,369 1,685 3,385 299 — — Industrial 3,764 1,507 1,921 336 — — Other 102 14 79 9 — — Total retail electric revenues 15,839 5,844 9,049 946 — — Natural gas distribution revenues Residential 2,843 — — — — 2,843 Commercial 763 — — — — 763 Transportation 1,186 — — — — 1,186 Industrial 84 — — — — 84 Other 342 — — — — 342 Total natural gas distribution revenues 5,218 — — — — 5,218 Wholesale electric revenues PPA energy revenues 2,274 489 130 16 1,673 — PPA capacity revenues 596 194 47 4 356 — Non-PPA revenues 250 200 30 690 740 — Total wholesale electric revenues 3,120 883 207 710 2,769 — Other natural gas revenues Gas marketing services 636 — — — — 636 Other natural gas revenues 51 — — — — 51 Total other natural gas revenues 687 — — — — 687 Other revenues 1,077 194 446 47 36 — Total revenue from contracts with customers 25,941 6,921 9,702 1,703 2,805 5,905 Other revenue sources (a) 3,338 896 1,882 (9) 564 57 Total operating revenues $ 29,279 $ 7,817 $ 11,584 $ 1,694 $ 3,369 $ 5,962 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2021 Operating revenues Retail electric revenues Residential $ 6,207 $ 2,467 $ 3,471 $ 269 $ — $ — Commercial 4,877 1,600 3,010 267 — — Industrial 3,067 1,386 1,391 290 — — Other 93 17 68 8 — — Total retail electric revenues 14,244 5,470 7,940 834 — — Natural gas distribution revenues Residential 1,799 — — — — 1,799 Commercial 470 — — — — 470 Transportation 1,038 — — — — 1,038 Industrial 49 — — — — 49 Other 269 — — — — 269 Total natural gas distribution revenues 3,625 — — — — 3,625 Wholesale electric revenues PPA energy revenues 1,122 184 95 11 854 — PPA capacity revenues 493 115 55 5 323 — Non-PPA revenues 236 170 21 401 398 — Total wholesale electric revenues 1,851 469 171 417 1,575 — Other natural gas revenues Wholesale gas services 2,168 — — — — 2,168 Gas marketing services 464 — — — — 464 Other natural gas revenues 36 — — — — 36 Total other natural gas revenues 2,668 — — — — 2,668 Other revenues 1,075 202 452 31 30 — Total revenue from contracts with customers 23,463 6,141 8,563 1,282 1,605 6,293 Other revenue sources (a) 3,349 272 697 40 611 1,786 Other adjustments (b) (3,699) — — — — (3,699) Total operating revenues $ 23,113 $ 6,413 $ 9,260 $ 1,322 $ 2,216 $ 4,380 (a) Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues (including those related to fuel costs ) that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies. (b) Other adjustments relate to the cost of Southern Company Gas' energy and risk management activities. Wholesale gas services revenues are presented net of the related costs of those activities on the statement of income. See Notes 15 and 16 under "Southern Company Gas" for information on the sale of Sequent and components of wholesale gas services' operating revenues, respectively.
Contract with customer, asset and liability	The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2023 and 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At December 31, 2023 $ 2,820 $ 821 $ 1,011 $ 90 $ 122 $ 684 At December 31, 2022 3,123 696 922 92 237 1,107 Contract Assets At December 31, 2023 $ 271 $ 2 $ 121 $ — $ — $ 56 At December 31, 2022 156 2 89 — — — Contract Liabilities At December 31, 2023 $ 116 $ — $ 1 $ — $ 4 $ — At December 31, 2022 45 4 9 — 1 —
Revenue, remaining performance obligation, expected timing of satisfaction	Revenues from contracts with customers related to these performance obligations remaining at December 31, 2023 are expected to be recognized as follows: 2024 2025 2026 2027 2028 Thereafter (in millions) Southern Company $ 940 $ 552 $ 338 $ 332 $ 323 $ 2,045 Alabama Power 23 9 — — — — Georgia Power 73 41 14 15 15 9 Mississippi Power 60 63 66 69 73 — Southern Power 379 301 299 306 297 2,041 Southern Company Gas 26 — — — — —

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT (Tables)	12 Months Ended
PROPERTY, PLANT, AND EQUIPMENT (Tables)	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Property, plant and equipment	The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2023 and 2022: At December 31, 2023: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 57,325 $ 16,584 $ 22,587 $ 2,909 $ 14,649 $ — Transmission 15,561 6,152 8,402 966 — — Distribution 26,482 9,775 15,380 1,327 — — General/other 6,305 2,918 3,001 321 41 — Electric utilities' plant in service 105,673 35,429 49,370 5,523 14,690 — Southern Company Gas: Natural gas transportation and distribution 17,798 — — — — 17,798 Storage facilities 1,565 — — — — 1,565 Other 1,477 — — — — 1,477 Southern Company Gas plant in service 20,840 — — — — 20,840 Other plant in service 1,915 — — — — — Total plant in service $ 128,428 $ 35,429 $ 49,370 $ 5,523 $ 14,690 $ 20,840 At December 31, 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 51,756 $ 15,920 $ 17,755 $ 2,826 $ 14,619 $ — Transmission 14,201 5,658 7,576 927 — — Distribution 24,200 9,154 13,819 1,228 — — General/other 5,806 2,740 2,729 273 39 — Electric utilities' plant in service 95,963 33,472 41,879 5,254 14,658 — Southern Company Gas: Natural gas transportation and distribution 16,810 — — — — 16,810 Storage facilities 1,553 — — — — 1,553 Other 1,360 — — — — 1,360 Southern Company Gas plant in service 19,723 — — — — 19,723 Other plant in service 1,843 — — — — — Total plant in service $ 117,529 $ 33,472 $ 41,879 $ 5,254 $ 14,658 $ 19,723 Southern Power Generating Facility Useful life Natural gas Up to 50 years Solar Up to 35 years Wind Up to 35 years
Deferred cloud implementation costs	At December 31, 2023 and 2022, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Deferred cloud implementation costs, net: At December 31, 2023 $ 325 $ 85 $ 99 $ 13 $ 15 $ 43 At December 31, 2022 345 81 108 14 18 54
Composite straight-line rates	Costs for these services from SCS in 2023, 2022, and 2021 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2023 $ 611 $ 857 $ 113 $ 86 $ 261 2022 549 762 115 86 262 2021 504 663 120 89 239 Mississippi Southern (in millions) 2023 $ 4 $ 13 2022 4 29 2021 9 15 Alabama Georgia Southern Southern Company Gas (in millions) 2023 $ 12 $ 101 $ 34 $ 28 2022 18 99 37 27 2021 14 108 31 29 2023 2022 2021 Alabama Power 4.1 % 2.7 % 2.7 % Georgia Power 3.8 % 3.3 % 3.3 % Mississippi Power 3.4 % 3.4 % 3.6 % Southern Company Gas 2.7 % 2.7 % 2.8 %
Ownership and investment in jointly-owned facilities	At December 31, 2023, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows: Facility (Type) Percent Plant in Service Accumulated CWIP (in millions) Alabama Power Greene County (natural gas) Units 1 and 2 60.0 % (a) $ 191 $ 113 $ 1 Plant Miller (coal) Units 1 and 2 91.8 (b) 2,156 778 40 Georgia Power Plant Hatch (nuclear) Units 1 and 2 50.1 % (c) $ 1,446 $ 659 $ 70 Plant Vogtle (nuclear) Units 1 and 2 45.7 (c) 3,664 2,331 62 Plant Vogtle (nuclear) Units 3 and 4 45.7 (c)(d) 4,613 19 3,232 Plant Scherer (coal) Units 1 and 2 8.4 (c) 287 123 2 Plant Scherer (coal) Unit 3 75.0 (c) 1,310 639 10 Rocky Mountain (pumped storage) 25.4 (e) 181 153 — Mississippi Power Greene County (natural gas) Units 1 and 2 40.0 % (a) $ 125 $ 80 $ — Plant Daniel (coal) Units 1 and 2 50.0 (f) 805 281 1 Southern Company Gas Dalton Pipeline (natural gas pipeline) 50.0 % (g) $ 271 $ 27 $ — (a) Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power. (b) Jointly owned with PowerSouth and operated and maintained by Alabama Power. (c) Georgia Power owns undivided interests in Plants Hatch, Vogtle, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and JEA. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third party claims related to these plants. (d) Unit 4 remains under construction. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (e) Jointly owned with OPC, which is the operator of the plant. (f) Jointly owned by FP&L and Mississippi Power. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 3 under "Other Matters – Mississippi Power – Plant Daniel" for additional information. (g) Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff.

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
ASSET RETIREMENT OBLIGATIONS (Tables)	Dec. 31, 2023
Asset Retirement Obligation Disclosure [Abstract]
Details of AROs included in the balance sheets	Details of the AROs included in the balance sheets are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power () (in millions) Balance at December 31, 2021 $ 11,687 $ 4,334 $ 6,824 $ 190 $ 131 Liabilities incurred 36 — 35 — — Liabilities settled (455) (205) (212) (20) — Accretion expense 406 158 231 6 6 Cash flow revisions (834) — (844) 3 7 Balance at December 31, 2022 $ 10,840 $ 4,287 $ 6,034 $ 179 $ 144 Liabilities incurred 90 — 90 — — Liabilities settled (617) (270) (304) (18) — Accretion expense 403 156 230 5 6 Cash flow revisions (399) (15) (385) 2 — Balance at December 31, 2023 $ 10,317 $ 4,158 $ 5,665 $ 168 $ 150 () Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Investment securities in the Funds	Investment securities in the Funds for December 31, 2023 and 2022 were as follows: Southern Company Alabama Georgia (in millions) At December 31, 2023: Equity securities $ 1,288 $ 796 $ 492 Debt securities 895 277 618 Other securities 239 186 53 Total investment securities in the Funds $ 2,422 $ 1,259 $ 1,163 At December 31, 2022: Equity securities $ 1,095 $ 690 $ 405 Debt securities 838 267 571 Other securities 210 168 42 Total investment securities in the Funds () $ 2,143 $ 1,125 $ 1,018 () For Southern Company and Georgia Power, these amounts include investment securities pledged to creditors and collateral received and excludes payables related to a securities lending program Georgia Power's Funds previously participated in through the managers of the Funds. Under this program, Georgia Power's Funds' investment securities were loaned to institutional investors for a fee. Securities loaned were fully collateralized by cash, letters of credit, and/or securities issued or guaranteed by the U.S. government or its agencies or instrumentalities. At December 31, 2022, approximately $35 million of the fair market value of Georgia Power's Funds' securities were on loan and pledged to creditors under the Funds' managers' securities lending program. At December 31, 2022, the fair value of the collateral received was approximately $36 million and could only be sold by the borrower upon the return of the loaned securities. The collateral received was treated as a non-cash item in the statements of cash flows.
Fair value increases (decreases) of the Funds	The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2023, 2022, and 2021 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2023 $ 281 $ 157 $ 124 2022 (360) (171) (189) 2021 274 200 74 Unrealized gains (losses) At December 31, 2023 $ 241 $ 119 $ 122 At December 31, 2022 (391) (204) (187) At December 31, 2021 (27) (30) 3 At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 6 $ 49 $ — $ — $ 55 Investments in trusts: (b) Domestic equity 764 216 — — 980 Foreign equity 145 171 — — 316 U.S. Treasury and government agency securities — 369 — — 369 Municipal bonds — 48 — — 48 Pooled funds – fixed income — 6 — — 6 Corporate bonds — 389 — — 389 Mortgage and asset backed securities — 89 — — 89 Private equity — — — 169 169 Cash and cash equivalents 3 — — — 3 Other 58 3 — 9 70 Cash equivalents and restricted cash 253 15 — — 268 Other investments 9 27 8 — 44 Total $ 1,238 $ 1,382 $ 8 $ 178 $ 2,806 Liabilities: Energy-related derivatives (a) $ 46 $ 312 $ — $ — $ 358 Interest rate derivatives — 264 — — 264 Foreign currency derivatives — 122 — — 122 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 49 $ 711 $ 16 $ — $ 776 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Nuclear decommissioning trusts: (b) Domestic equity 443 208 — — 651 Foreign equity 145 — — — 145 U.S. Treasury and government agency securities — 20 — — 20 Municipal bonds — 1 — — 1 Corporate bonds — 231 — — 231 Mortgage and asset backed securities — 25 — — 25 Private equity — — — 169 169 Other 8 — — 9 17 Cash equivalents and restricted cash 119 15 — — 134 Other investments — 27 — — 27 Total $ 715 $ 542 $ — $ 178 $ 1,435 Liabilities: Energy-related derivatives $ — $ 110 $ — $ — $ 110 Georgia Power Assets: Energy-related derivatives $ — $ 13 $ — $ — $ 13 Nuclear decommissioning trusts: (b) Domestic equity 321 1 — — 322 Foreign equity — 170 — — 170 U.S. Treasury and government agency securities — 349 — — 349 Municipal bonds — 47 — — 47 Corporate bonds — 158 — — 158 Mortgage and asset backed securities — 64 — — 64 Other 50 3 — — 53 Total $ 371 $ 805 $ — $ — $ 1,176 Liabilities: Energy-related derivatives $ — $ 124 $ — $ — $ 124 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Cash equivalents 17 — — — 17 Total $ 17 $ 15 $ — $ — $ 32 Liabilities: Energy-related derivatives $ — $ 61 $ — $ — $ 61 Southern Power Assets: Energy-related derivatives $ — $ 3 $ — $ — $ 3 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Foreign currency derivatives — 22 — — 22 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 3 $ 40 $ 16 $ — $ 59 Southern Company Gas Assets: Energy-related derivatives (a) $ 6 $ 3 $ — $ — $ 9 Non-qualified deferred compensation trusts: Domestic equity — 7 — — 7 Foreign equity — 1 — — 1 Pooled funds - fixed income — 6 — — 6 Cash and cash equivalents 3 — — — 3 Total $ 9 $ 17 $ — $ — $ 26 Liabilities: Energy-related derivatives (a)(b) $ 46 $ 12 $ — $ — $ 58 Interest rate derivatives — 79 — — 79 Total $ 46 $ 91 $ — $ — $ 137 (a) Excludes cash collateral of $62 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information.
Accumulated provisions for the external decommissioning trust funds	At December 31, 2023 and 2022, the accumulated provisions for the external decommissioning trust funds were as follows: 2023 2022 (in millions) Alabama Power Plant Farley $ 1,259 $ 1,125 Georgia Power Plant Hatch $ 705 $ 628 Plant Vogtle Units 1 and 2 434 382 Plant Vogtle Units 3 and 4 24 8 Total $ 1,163 $ 1,018
Estimated costs of decommissioning	The estimated costs of decommissioning at December 31, 2023 based on the most current studies were as follows: Alabama Power Georgia Power Plant Plant Hatch () Plant Vogtle Units 1 and 2 () Plant Vogtle Unit 3 () Most current study year 2023 2021 2021 2020 Decommissioning periods: Beginning year 2037 2034 2047 2063 Completion year 2087 2075 2079 2074 (in millions) Site study costs: Radiated structures $ 1,402 $ 771 $ 628 $ 284 Spent fuel management 513 186 170 30 Non-radiated structures 133 61 85 33 Total site study costs $ 2,048 $ 1,018 $ 883 $ 347 () Based on Georgia Power's ownership interests.

CONSOLIDATED ENTITIES AND EQU_2

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2023
Equity Method Investments and Joint Ventures [Abstract]
Equity method investments	The carrying amounts of Southern Company Gas' equity method investments at December 31, 2023 and 2022 and related earnings (loss) from those investments for the years ended December 31, 2023, 2022, and 2021 were as follows: Investment Balance December 31, 2023 December 31, 2022 (in millions) SNG $ 1,202 $ 1,243 Other 33 33 Total $ 1,235 $ 1,276
Equity method investments related income	Earnings (Loss) from Equity Method Investments 2023 2022 2021 (in millions) SNG $ 139 $ 146 $ 127 PennEast Pipeline () — — (81) Other 1 2 4 Total $ 140 $ 148 $ 50 () For 2021, includes pre-tax impairment charges totaling $84 million. See "PennEast Pipeline Project" herein for additional information, including the September 2021 cancellation of the project.

FINANCING (Tables)

FINANCING (Tables)	12 Months Ended
FINANCING (Tables)	Dec. 31, 2023
Debt Disclosure [Abstract]
Summary of long-term debt	Details of long-term debt at December 31, 2023 and 2022 are provided in the following table: At December 31, 2023 Balance Outstanding at Maturity Weighted Average 2023 2022 (in millions) Southern Company Senior notes (a) 2024-2073 4.16% $ 40,235 $ 35,683 Junior subordinated notes 2024-2081 4.33% 8,333 8,836 FFB loans (b) 2024-2044 2.88% 4,788 4,874 Revenue bonds (c) 2024-2063 3.77% 3,400 2,844 First mortgage bonds (d) 2025-2063 3.64% 2,500 2,275 Medium-term notes 2026-2027 7.03% 84 84 Other long-term debt 2024-2045 5.44% 234 167 Finance lease obligations (e) 298 314 Unamortized fair value adjustment 302 330 Unamortized debt premium (discount), net (198) (193) Unamortized debt issuance expenses (290) (273) Total long-term debt 59,686 54,941 Less: Amount due within one year 2,476 4,285 Total long-term debt excluding amount due within one year $ 57,210 $ 50,656 Alabama Power Senior notes 2025-2073 3.95% $ 9,875 $ 9,675 Revenue bonds (c) 2024-2063 3.94% 1,321 995 Other long-term debt 2026-2030 7.04% 75 45 Finance lease obligations (e) 5 5 Unamortized debt premium (discount), net (20) (18) Unamortized debt issuance expenses (73) (72) Total long-term debt 11,183 10,630 Less: Amount due within one year 223 301 Total long-term debt excluding amount due within one year $ 10,960 $ 10,329 Georgia Power Senior notes 2024-2052 4.34% $ 9,575 $ 7,925 Junior subordinated notes 2077 5.00% 270 270 FFB loans (b) 2024-2044 2.88% 4,788 4,874 Revenue bonds (c) 2025-2062 3.64% 1,968 1,738 Finance lease obligations (e) 240 238 Unamortized debt premium (discount), net (19) (18) Unamortized debt issuance expenses (122) (117) Total long-term debt 16,700 14,910 Less: Amount due within one year 502 901 Total long-term debt excluding amount due within one year $ 16,198 $ 14,009 At December 31, 2023 Balance Outstanding at Maturity Weighted Average 2023 2022 (in millions) Mississippi Power Senior notes 2024-2051 4.27% $ 1,525 $ 1,425 Revenue bonds (c) 2025-2052 4.08% 111 111 Finance lease obligations (e) 16 17 Unamortized debt premium (discount), net 1 2 Unamortized debt issuance expenses (9) (10) Total long-term debt 1,644 1,545 Less: Amount due within one year 201 1 Total long-term debt excluding amount due within one year $ 1,443 $ 1,544 Southern Power Senior notes (a) 2025-2046 4.05% $ 2,728 $ 2,998 Unamortized debt premium (discount), net (4) (5) Unamortized debt issuance expenses (13) (14) Total long-term debt 2,711 2,979 Less: Amount due within one year — 290 Total long-term debt excluding amount due within one year $ 2,711 $ 2,689 Southern Company Gas Senior notes 2025-2051 4.36% $ 4,930 $ 4,769 First mortgage bonds (d) 2025-2063 3.64% 2,500 2,275 Medium-term notes 2026-2027 7.03% 84 84 Other long-term debt 2024-2045 3.81% 59 22 Unamortized fair value adjustment 302 330 Unamortized debt premium (discount), net (8) (8) Unamortized debt issuance expenses (34) (30) Total long-term debt 7,833 7,442 Less: Amount due within one year — 400 Total long-term debt excluding amount due within one year $ 7,833 $ 7,042 (a) Includes a fair value gain (loss) of $(12) million and $(31) million at December 31, 2023 and 2022, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes. (b) Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred. (d) Secured by substantially all of Nicor Gas' properties. (e) Secured by the underlying lease ROU asset. See Note 9 for additional information.
Schedule of maturities of long-term debt for the next five years	Maturities of long-term debt for the next five years are as follows: Southern Company (a) Alabama Power (b) Georgia Power (c) Mississippi Power Southern Power (d) Southern Company (in millions) 2024 $ 2,480 $ 223 $ 503 $ 201 $ — $ — 2025 4,124 251 849 12 500 300 2026 3,791 46 448 66 964 530 2027 2,075 551 512 10 — 154 2028 2,612 107 864 357 — 150 (a) See notes (b) and (c) below. (b) Alabama Power's 2024 maturities include $200 million aggregate principal amount of Series 2023A Floating Rate Senior Notes due May 15, 2073 that are repayable at the option of the holders at certain dates beginning in 2024. As a result, the senior notes are classified as securities due within one year on the balance sheets of Southern Company and Alabama Power at December 31, 2023. (c) Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. (d) Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar denominated hedge settlement amount.
Summary of committed credit arrangements	At December 31, 2023, committed credit arrangements with banks were as follows: Expires Company 2024 2025 2026 2028 Total Unused Expires within One Year (in millions) Southern Company parent (a) $ 150 $ — $ — $ 1,850 $ 2,000 $ 1,998 $ 150 Alabama Power — — 650 700 1,350 1,350 — Georgia Power — — — 1,750 1,750 1,726 — Mississippi Power — 125 150 — 275 275 — Southern Power (a)(b) — — — 600 600 589 — Southern Company Gas (c) 100 — — 1,500 1,600 1,598 100 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 125 $ 800 $ 6,400 $ 7,605 $ 7,566 $ 280 (a) Arrangement expiring in 2028 represents a $2.45 billion combined arrangement for Southern Company and Southern Power as borrowers. Pursuant to the combined facility, the allocations between Southern Company and Southern Power may be adjusted. (b) Does not include Southern Power Company's $75 million and $100 million continuing letter of credit facilities for standby letters of credit, expiring in 2025 and 2026, respectively , of which $8 million and $7 million, respectively, was unused at December 31, 2023. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities. (c) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2028. Southern Company Gas' committed credit arrangement expiring in 2028 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2028, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $100 million credit arrangement expiring in 2024. See "Structural Considerations" herein for additional information.
Details of short-term borrowings	Details of short-term borrowings for the applicable Registrants were as follows: Notes Payable at December 31, 2023 Notes Payable at December 31, 2022 Amount Weighted Average Amount Weighted Average (in millions) (in millions) Southern Company Commercial paper $ 1,794 5.6 % $ 809 4.7 % Short-term bank debt 520 6.4 % 1,800 5.0 % Total $ 2,314 5.7 % $ 2,609 4.9 % Alabama Power Commercial paper $ 40 5.5 % $ — — % Georgia Power Commercial paper $ 809 5.6 % $ — — % Short-term bank debt 520 6.4 % 1,600 5.0 % Total $ 1,329 5.9 % $ 1,600 5.0 % Southern Power Commercial paper $ 138 5.5 % $ 225 4.7 % Southern Company Gas Commercial paper: Southern Company Gas Capital $ 23 5.5 % $ 285 4.8 % Nicor Gas 392 5.5 % 283 4.6 % Short-term bank debt: Nicor Gas — — % 200 4.9 % Total $ 415 5.5 % $ 768 4.7 %
Shares used to compute diluted EPS	Shares used to compute diluted EPS were as follows: Average Common Stock Shares 2023 2022 2021 (in millions) As reported shares 1,092 1,075 1,061 Effect of stock-based compensation 6 6 7 Diluted shares 1,098 1,081 1,068
Schedule of preferred stock	Preferred Stock Redeemed During 2022 Par Value/Stated Capital Per Share Shares Redemption 4.92% Preferred Stock $100 80,000 $103.23 4.72% Preferred Stock $100 50,000 $102.18 4.64% Preferred Stock $100 60,000 $103.14 4.60% Preferred Stock $100 100,000 $104.20 4.52% Preferred Stock $100 50,000 $102.93 4.20% Preferred Stock $100 135,115 $105.00 5.00% Class A Preferred Stock $25 10,000,000 $25.00

LEASES (Tables)

LEASES (Tables)	12 Months Ended
LEASES (Tables)	Dec. 31, 2023
Leases [Abstract]
Major categories of lease obligations	The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Electric generating units () $ 670 $ 58 $ 1,028 $ — $ — $ — Real estate/land 871 4 54 2 546 28 Communication towers 123 1 4 — — 23 Railcars 64 32 27 5 — — Other 60 3 2 18 — — Total $ 1,788 $ 98 $ 1,115 $ 25 $ 546 $ 51 At December 31, 2022 Electric generating units () $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Balance sheet amounts recorded for operating and financing leases	Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2023 Operating Leases Operating lease ROU assets, net $ 1,432 $ 87 $ 884 $ 9 $ 488 $ 47 Operating lease obligations - current $ 183 $ 12 $ 135 $ 3 $ 29 $ 11 Operating lease obligations - non-current 1,307 81 740 6 517 40 Total operating lease obligations () $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance Leases Finance lease ROU assets, net $ 272 $ 5 $ 203 $ 15 $ — $ — Finance lease obligations - current $ 11 $ 2 $ 18 $ 1 $ — $ — Finance lease obligations - non-current 287 3 222 15 — — Total finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ — At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations () $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $566 million, $58 million, and $813 million, respectively, at December 31, 2023 and $652 million, $59 million, and $952 million, respectively, at December 31, 2022.
Lease costs and other information	Lease costs for 2023, 2022, and 2021, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease cost Operating lease cost () $ 252 $ 16 $ 192 $ 5 $ 34 $ 12 Finance lease cost: Amortization of ROU assets 24 2 19 1 — — Interest on lease obligations 14 — 17 — — — Total finance lease cost 38 2 36 1 — — Short-term lease costs 40 16 16 — — — Variable lease cost 47 — 74 — 4 — Sublease income — — — — — — Total lease cost $ 377 $ 34 $ 318 $ 6 $ 38 $ 12 2022 Lease cost Operating lease cost () $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost () $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 () Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $112 million, $4 million, and $174 million, respectively, in 2023, $162 million, $48 million, and $180 million, respectively, in 2022, and $165 million, $47 million, and $184 million, respectively, in 2021. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2023 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 253 $ 17 $ 199 $ 5 $ 33 $ 12 Operating cash flows from finance leases 15 — 22 — — — Financing cash flows from finance leases 18 2 16 1 — — ROU assets obtained under operating leases 100 30 26 1 7 7 ROU assets obtained under finance leases 3 3 18 — — — 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2023 Weighted-average remaining lease term in years: Operating leases 17.2 11.1 7.5 4.6 33.1 7.0 Finance leases 16.7 4.3 10.6 11.9 N/A N/A Weighted-average discount rate: Operating leases 4.68 % 5.02 % 4.58 % 3.67 % 4.89 % 3.80 % Finance leases 4.85 % 3.93 % 5.95 % 2.74 % N/A N/A At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A
Maturities of operating lease liabilities	Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ —
Maturities of finance lease liabilities	Maturities of lease liabilities are as follows: At December 31, 2023 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2024 $ 230 $ 16 $ 172 $ 4 $ 36 $ 12 2025 203 14 147 3 29 12 2026 180 12 142 2 29 9 2027 159 10 141 — 29 4 2028 143 7 135 — 30 3 Thereafter 1,378 64 303 1 1,000 18 Total 2,293 123 1,040 10 1,153 58 Less: Present value discount 803 30 165 1 607 7 Operating lease obligations $ 1,490 $ 93 $ 875 $ 9 $ 546 $ 51 Finance leases: 2024 $ 22 $ 2 $ 27 $ 2 $ — $ — 2025 27 1 36 2 — — 2026 27 1 36 2 — — 2027 27 1 36 2 — — 2028 26 1 37 1 — — Thereafter 320 — 153 10 — — Total 449 6 325 19 — — Less: Present value discount 151 1 85 3 — — Finance lease obligations $ 298 $ 5 $ 240 $ 16 $ — $ —
Lease income, operating leases	Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35
Lease income, sales-type leases and Power Purchase Agreements	Lease income for 2023, 2022, and 2021, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2023 Lease income - interest income on sales-type leases $ 24 $ — $ — $ 14 $ 10 $ — Lease income - operating leases 164 35 29 2 85 37 Variable lease income 406 1 — — 437 — Total lease income $ 594 $ 36 $ 29 $ 16 $ 532 $ 37 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35
Undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases	The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2023 Southern Company Mississippi Power Southern (in millions) 2024 $ 38 $ 23 $ 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 2028 34 19 15 Thereafter 330 145 185 Total undiscounted cash flows $ 510 $ 250 $ 260 Net investment in sales-type lease () 311 148 163 Difference between undiscounted cash flows and discounted cash flows $ 199 $ 102 $ 97 () For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $15 million at December 31, 2023 and 2022, respectively) and net investment in sales-type leases ($148 million and $154 million at December 31, 2023 and 2022, respectively) on the balance sheet.
Undiscounted cash flows to be received under PPAs accounted for as operating leases	The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2023 Southern Alabama Southern Southern Company Gas (in millions) 2024 $ 116 $ 7 $ 90 $ 35 2025 107 5 75 29 2026 108 5 73 29 2027 105 4 75 28 2028 104 3 76 28 Thereafter 706 26 91 354 Total $ 1,246 $ 50 $ 480 $ 503
Summary of the components of income from leveraged leases	The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 (in millions) Pretax leveraged lease income $ 17 Income tax expense (5) Net leveraged lease income $ 12

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
INCOME TAXES (Tables)	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Details of income tax provisions	Details of income tax provisions are as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 54 $ 242 $ 205 $ 49 $ (320) $ 62 Deferred 299 (257) 195 (26) 334 68 Total federal 353 (15) 400 23 14 130 State — Current 41 82 37 1 (1) 24 Deferred 102 14 11 12 (1) 57 Total state 143 96 48 13 (2) 81 Total $ 496 $ 81 $ 448 $ 36 $ 12 $ 211 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 10 $ 54 $ 38 $ 42 $ (43) $ 122 Deferred 455 259 152 (16) 56 (3) Total federal 465 313 190 26 13 119 State — Current 27 14 (21) — 2 42 Deferred 303 96 201 11 5 19 Total state 330 110 180 11 7 61 Total $ 795 $ 423 $ 370 $ 37 $ 20 $ 180 2021 Southern Company Alabama Power Georgia Mississippi Southern Power Southern Company Gas (in millions) Federal — Current $ 50 $ 104 $ 311 $ 25 $ (340) $ 85 Deferred 36 172 (449) (15) 343 35 Total federal 86 276 (138) 10 3 120 State — Current (25) 23 71 — (16) (68) Deferred 206 73 (101) 11 — 223 Total state 181 96 (30) 11 (16) 155 Total $ 267 $ 372 $ (168) $ 21 $ (13) $ 275
Summary of amortization of tax credits	ITCs amortized in 2023, 2022, and 2021 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power: Southern Company Southern Power (in millions) 2023 $ 84 $ 58 2022 83 58 2021 84 58
Schedule of effective income tax reconciliation	A reconciliation of the federal statutory income tax rate to the effective income tax rate is as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 2.6 5.2 1.5 4.9 (0.7) 7.8 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.7 0.7 0.8 0.4 — — Flowback of excess deferred income taxes (9.2) (19.8) (2.6) (10.2) — (2.6) AFUDC-Equity (1.1) (1.2) (1.2) — — — Federal PTCs (1.2) — (1.4) — (7.4) — ITC amortization (1.3) (0.1) (0.1) — (19.0) — Noncontrolling interests 0.6 — — — 11.1 — Other (0.2) (0.2) (0.3) 0.1 0.1 (0.6) Effective income tax (benefit) rate 11.4 % 5.6 % 17.7 % 16.2 % 5.1 % 25.6 % 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 6.2 4.8 6.5 4.4 1.9 6.4 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.6 0.5 0.6 0.3 — — Flowback of excess deferred income taxes (6.6) (1.9) (9.6) (7.8) — (2.5) AFUDC-Equity (1.1) (0.8) (1.5) — — — Federal PTCs — — — — (6.6) — ITC amortization (1.3) (0.1) (0.1) — (17.2) (0.1) Noncontrolling interests 0.5 — — — 8.4 — Other — 0.3 — 0.3 (0.1) (0.9) Effective income tax (benefit) rate 18.8 % 23.8 % 16.9 % 18.2 % 7.4 % 23.9 % 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 5.5 4.6 (5.7) 4.9 (8.0) 15.1 Employee stock plans' dividend deduction (0.9) — — — — — Non-deductible book depreciation 0.9 0.5 3.1 0.4 — — Flowback of excess deferred income taxes (11.7) (2.6) (49.9) (15.2) — (2.8) AFUDC-Equity (1.5) (0.7) (6.4) — — — Federal PTCs — — — — (4.6) — ITC amortization (2.2) (0.1) (0.4) — (29.7) (0.1) Noncontrolling interests 0.8 — — — 13.4 — Leveraged lease impairments and dispositions (1.4) — — — — — Other (0.1) 0.2 (1.9) 0.6 (0.4) 0.6 Effective income tax (benefit) rate 10.4 % 22.9 % (40.2) % 11.7 % (8.3) % 33.8 %
Tax effects between the carrying amounts of assets and liabilities	The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows: December 31, 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,683 $ 2,566 $ 3,628 $ 339 $ 1,346 $ 1,576 Property basis differences 2,647 1,444 812 188 — 189 Employee benefit obligations 979 321 446 49 12 74 AROs 833 476 314 — — — Under recovered fuel and natural gas costs 601 80 508 13 — — Regulatory assets – AROs 1,902 667 1,196 39 — — Employee benefit obligations 797 213 260 37 — 11 Remaining book value of retired assets 369 143 221 5 — — Premium on reacquired debt 63 9 53 1 — — Other 700 182 223 43 2 191 Total deferred income tax liabilities 18,574 6,101 7,661 714 1,360 2,041 Deferred tax assets — AROs 2,735 1,143 1,510 39 — — ITC and PTC carryforwards 1,387 12 691 — 481 — Employee benefit obligations 985 224 316 52 10 89 Estimated loss on plants under construction 857 — 857 — — — Estimated loss on regulatory disallowance 26 — — — — 26 Other state deferred tax attributes 363 — 13 231 49 8 Federal effect of net state deferred tax liabilities 418 215 92 — 27 101 Other property basis differences 197 — 83 — 97 — State effect of federal deferred taxes 115 115 — — — — Other partnership basis differences 85 — — — 85 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 34 30 — 3 — — Long-term debt fair value adjustment 79 — — — — 79 Other comprehensive losses 67 4 4 — 6 — Other 538 188 152 57 18 74 Total deferred income tax assets 7,886 1,931 3,718 382 773 377 Valuation allowance (206) — (75) (41) (27) (7) Net deferred income tax assets 7,680 1,931 3,643 341 746 370 Net deferred income taxes (assets)/liabilities $ 10,894 $ 4,170 $ 4,018 $ 373 $ 614 $ 1,671 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (96) $ — $ — $ (96) $ — $ — Accumulated deferred income taxes – liabilities $ 10,990 $ 4,170 $ 4,018 $ 469 $ 614 $ 1,671 December 31, 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,443 $ 2,564 $ 3,447 $ 338 $ 1,351 $ 1,505 Property basis differences 2,350 1,303 693 179 — 150 Employee benefit obligations 888 284 412 43 11 68 AROs 876 499 324 — — — Under recovered fuel and natural gas costs 805 185 548 40 — 32 Regulatory assets – AROs 2,006 679 1,285 42 — — Employee benefit obligations 677 180 226 30 — 15 Remaining book value of retired assets 400 142 253 5 — — Premium on reacquired debt 66 9 57 — — — Other 555 179 181 40 14 82 Total deferred income tax liabilities 18,066 6,024 7,426 717 1,376 1,852 Deferred tax assets — AROs 2,882 1,178 1,609 42 — — ITC and PTC carryforwards 1,685 12 673 — 794 — Employee benefit obligations 890 198 304 47 9 89 Estimated loss on plants under construction 888 — 888 — — — Other state deferred tax attributes 388 — 12 239 51 7 Federal effect of net state deferred tax liabilities 365 175 88 — 28 92 Other property basis differences 207 — 79 — 109 — State effect of federal deferred taxes 136 136 — — — — Other partnership basis differences 111 — — — 111 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 137 127 — 9 — — Long-term debt fair value adjustment 85 — — — — 85 Other comprehensive losses 72 4 5 — 5 — Other 552 213 186 62 17 28 Total deferred income tax assets 8,398 2,043 3,844 399 1,124 301 Valuation allowance (257) — (125) (41) (27) (9) Net deferred income tax assets 8,141 2,043 3,719 358 1,097 292 Net deferred income taxes (assets)/liabilities $ 9,925 $ 3,981 $ 3,707 $ 359 $ 279 $ 1,560 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (111) $ — $ — $ (107) $ — $ — Accumulated deferred income taxes – liabilities $ 10,036 $ 3,981 $ 3,707 $ 466 $ 279 $ 1,560
Summary of tax credit carryforwards	Federal ITC/PTC carryforwards at December 31, 2023 were as follows: Southern Company Alabama Georgia Southern (in millions) Federal ITC/PTC carryforwards $ 829 $ 12 $ 131 $ 481 Tax year in which federal ITC/PTC carryforwards begin expiring 2031 2032 2031 2035 Year by which federal ITC/PTC carryforwards are expected to be utilized 2029 2028 2028 2029
Summary of operating loss carryforward	At December 31, 2023, the net state income tax benefit of state and local NOL carryforwards for Southern Company's subsidiaries were as follows: Company/Jurisdiction Approximate Net State Income Tax Benefit of NOL Carryforwards Tax Year NOL (in millions) Mississippi Power Mississippi $ 183 2032 Southern Power Oklahoma 26 2035 Florida 10 2034 Other states 2 Various Southern Power Total $ 38 Other () New York 11 2036 New York City 14 2036 Other states 30 Various Southern Company Total $ 276 () Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2023.
Changes in unrecognized tax benefits	Changes in unrecognized tax benefits for the periods presented were as follows: Southern Company Georgia Power Southern (in millions) Unrecognized tax benefits at December 31, 2020 $ 44 $ — $ — Tax positions changes – Increase from prior periods 3 — — Unrecognized tax benefits at December 31, 2021 47 — — Tax positions changes – Increase from prior periods 33 — 32 Unrecognized tax benefits at December 31, 2022 80 — 32 Tax positions changes – Increase from prior periods 88 86 2 Statute of limitations expiration (52) (9) — Unrecognized tax benefits at December 31, 2023 $ 116 $ 77 $ 34

RETIREMENT BENEFITS (Tables)

RETIREMENT BENEFITS (Tables)	12 Months Ended
RETIREMENT BENEFITS (Tables)	Dec. 31, 2023
Retirement Benefits [Abstract]
Summary of actuarial assumptions	The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below. 2023 Assumptions used to determine net Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Discount rate – interest costs 5.13 5.14 5.12 5.12 5.19 5.12 Discount rate – service costs 5.36 5.38 5.38 5.37 5.37 5.31 Expected long-term return on plan assets 8.40 8.40 8.40 8.40 8.40 8.40 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Discount rate – interest costs 5.08 5.09 5.07 5.08 5.12 5.07 Discount rate – service costs 5.34 5.35 5.34 5.33 5.33 5.33 Expected long-term return on plan assets 7.67 7.95 7.49 7.43 — 6.59 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2022 Assumptions used to determine net Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Discount rate – interest costs 2.55 2.58 2.51 2.54 2.79 2.53 Discount rate – service costs 3.34 3.36 3.37 3.35 3.36 3.21 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Discount rate – interest costs 2.32 2.38 2.30 2.27 2.55 2.17 Discount rate – service costs 3.26 3.30 3.27 3.26 3.25 3.22 Expected long-term return on plan assets 7.21 7.54 6.88 7.22 — 6.08 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine net periodic costs: Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 2.81 % 2.85 % 2.79 % 2.80 % 2.99 % 2.75 % Discount rate – interest costs 2.13 2.17 2.09 2.12 2.46 2.10 Discount rate – service costs 3.18 3.23 3.21 3.20 3.22 2.97 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.56 % 2.63 % 2.52 % 2.53 % 2.78 % 2.46 % Discount rate – interest costs 1.84 1.91 1.82 1.78 2.12 1.64 Discount rate – service costs 3.07 3.13 3.08 3.06 3.05 3.01 Expected long-term return on plan assets 7.09 7.18 6.84 6.98 — 6.54 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2023 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.07 % 5.08 % 5.06 % 5.06 % 5.14 % 5.05 % Annual salary increase 4.60 4.60 4.60 4.60 4.60 4.60 Other postretirement benefit plans Discount rate 4.99 % 5.01 % 4.98 % 4.98 % 5.06 % 4.98 % Annual salary increase 4.60 4.60 4.60 4.60 4.60 4.60 2022 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80
Schedule of health care cost trend rates	The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2023 were as follows: Initial Cost Trend Rate Ultimate Cost Trend Rate Year That Ultimate Rate is Reached Pre-65 7.00 % 4.50 % 2032 Post-65 medical 5.50 4.50 2032 Post-65 prescription 8.50 4.50 2032
Schedule of accumulated and projected benefit obligations	The total accumulated benefit obligation for the pension plans at December 31, 2023 and 2022 was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2023 $ 11,991 $ 2,746 $ 3,674 $ 546 $ 145 $ 808 December 31, 2022 11,422 2,601 3,534 520 135 801 The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2023 are shown in the following table. All pension plan assets are related to the qualified pension plan. Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Projected benefit obligations: Qualified pension plan $ 12,540 $ 2,959 $ 3,865 $ 569 $ 154 $ 822 Non-qualified pension plan 713 117 145 29 22 60
Changes in projected benefit obligations and fair value of plan assets	Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2023 and 2022 were as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 12,602 $ 2,906 $ 3,851 $ 569 $ 163 $ 868 Service cost 275 64 68 11 6 24 Interest cost 626 145 191 28 8 42 Benefits paid (744) (155) (224) (32) (6) (104) Actuarial loss 493 116 123 23 6 52 Balance at end of year 13,252 3,076 4,009 599 177 882 Change in plan assets Fair value of plan assets at beginning of year 14,218 3,427 4,456 649 178 1,002 Actual return on plan assets 1,092 260 331 50 12 79 Employer contributions 52 11 9 2 2 3 Benefits paid (744) (154) (225) (32) (7) (104) Fair value of plan assets at end of year 14,618 3,544 4,571 669 185 980 Accrued asset $ 1,366 $ 468 $ 562 $ 70 $ 8 $ 98 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,382 $ 3,806 $ 5,012 $ 743 $ 222 $ 1,134 Service cost 412 99 103 17 9 34 Interest cost 408 96 123 18 6 28 Benefits paid (692) (144) (226) (30) (5) (75) Actuarial gain (3,908) (951) (1,161) (179) (69) (253) Balance at end of year 12,602 2,906 3,851 569 163 868 Change in plan assets Fair value of plan assets at beginning of year 17,225 4,141 5,415 786 213 1,241 Actual loss on plan assets (2,376) (579) (753) (110) (31) (167) Employer contributions 61 9 20 3 1 3 Benefits paid (692) (144) (226) (30) (5) (75) Fair value of plan assets at end of year 14,218 3,427 4,456 649 178 1,002 Accrued asset $ 1,616 $ 521 $ 605 $ 80 $ 15 $ 134
Amounts recognized in balance sheets	Amounts recognized in the balance sheets at December 31, 2023 and 2022 related to the Registrants' pension plans consist of the following: Southern Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2023: Prepaid pension costs (a) $ 2,079 $ 585 $ 706 $ 99 $ 31 $ 158 Other regulatory assets, deferred (b) 2,960 821 1,051 152 — 143 Other current liabilities (64) (11) (13) (2) (2) (3) Employee benefit obligations (c) (649) (106) (131) (27) (21) (58) Other regulatory liabilities, deferred (47) — — — — — AOCI 79 — — — 20 (45) December 31, 2022: Prepaid pension costs (a) $ 2,290 $ 629 $ 738 $ 108 $ 37 $ 183 Other regulatory assets, deferred (b) 2,455 679 887 123 — 111 Other current liabilities (56) (10) (12) (2) (2) (3) Employee benefit obligations (c) (618) (98) (121) (26) (20) (42) Other regulatory liabilities, deferred (85) — — — — — AOCI 24 — — — 11 (75) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in regulatory assets at December 31, 2023 and 2022 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2023 Regulatory assets: Prior service cost $ 9 $ 4 $ 6 $ 1 $ (7) Net loss 2,904 817 1,045 151 100 Regulatory amortization — — — — 50 Total regulatory assets () $ 2,913 $ 821 $ 1,051 $ 152 $ 143 Balance at December 31, 2022 Regulatory assets: Prior service cost $ 10 $ 4 $ 7 $ 1 $ (9) Net loss 2,361 675 880 122 66 Regulatory amortization — — — — 54 Total regulatory assets () $ 2,371 $ 679 $ 887 $ 123 $ 111 () Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. Amounts recognized in the balance sheets at December 31, 2023 and 2022 related to the Registrants' other postretirement benefit plans consist of the following: Southern Company Alabama Power Georgia Mississippi Power Southern Southern Company Gas (in millions) December 31, 2023: Prepaid other postretirement benefit costs (a) $ — $ 74 $ — $ — $ — $ — Other regulatory assets, deferred (b) 23 — 11 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (285) — (79) (32) (8) (44) Other regulatory liabilities, deferred (231) (48) (85) (10) — (68) AOCI (9) — — — 1 (10) December 31, 2022: Prepaid other postretirement benefit costs (a) $ — $ 28 $ — $ — $ — $ — Other regulatory assets, deferred (b) 34 — 19 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (437) — (146) (35) (8) (66) Other regulatory liabilities, deferred (170) (21) (58) (9) — (58) AOCI (4) — — — — (2) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2023 and 2022 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2023: Regulatory assets (liabilities): Prior service cost $ 13 $ 4 $ 5 $ 1 $ — Net gain (216) (52) (79) (11) (64) Regulatory amortization — — — — (4) Total regulatory assets (liabilities) () $ (203) $ (48) $ (74) $ (10) $ (68) Balance at December 31, 2022: Regulatory assets (liabilities): Prior service cost $ 14 $ 4 $ 6 $ 1 $ 1 Net gain (150) (25) (45) (10) (64) Regulatory amortization — — — — 5 Total regulatory assets (liabilities) () $ (136) $ (21) $ (39) $ (9) $ (58) () Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Changes in balances of regulatory assets and regulatory liabilities related to defined benefit pension plans	The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2023 and 2022 are presented in the following table: Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Regulatory assets (liabilities): () Balance at December 31, 2021 $ 2,801 $ 809 $ 971 $ 146 $ 91 Net (gain) loss (183) (67) (9) (12) 27 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net gain (loss) (246) (62) (74) (11) 1 Amortization of regulatory assets () — — — — (10) Total reclassification adjustments (247) (63) (75) (11) (7) Total change (430) (130) (84) (23) 20 Balance at December 31, 2022 $ 2,371 $ 679 $ 887 $ 123 $ 111 Net loss 576 153 178 31 34 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net loss (33) (10) (13) (2) — Amortization of regulatory assets () — — — — (4) Total reclassification adjustments (34) (11) (14) (2) (2) Total change 542 142 164 29 32 Balance at December 31, 2023 $ 2,913 $ 821 $ 1,051 $ 152 $ 143 () Amounts for Southern Company exclude regulatory assets of $173 million and $190 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Net regulatory assets (liabilities): () Balance at December 31, 2021 $ (74) $ (62) $ (10) $ 1 $ (34) Net (gain) loss (64) 41 (27) (10) (13) Reclassification adjustments: Amortization of prior service costs 1 — — — — Amortization of net gain (loss) 1 — (2) — — Amortization of regulatory assets () — — — — (11) Total reclassification adjustments 2 — (2) — (11) Total change (62) 41 (29) (10) (24) Balance at December 31, 2022 $ (136) $ (21) $ (39) $ (9) $ (58) Net gain (77) (30) (38) (1) — Reclassification adjustments: Amortization of prior service costs (1) — (1) — — Amortization of net gain 6 3 4 — — Amortization of regulatory assets () — — — — (10) Total reclassification adjustments 5 3 3 — (10) Total change (72) (27) (35) (1) (10) Balance at December 31, 2023 $ (208) $ (48) $ (74) $ (10) $ (68) () Amounts for Southern Company exclude regulatory assets of $24 million and $32 million at December 31, 2023 and 2022, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Amounts included in AOCI related to defined benefit pension plans	Presented below are the amounts included in AOCI at December 31, 2023 and 2022 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Southern Southern Company (in millions) Balance at December 31, 2023 AOCI: Prior service cost $ (1) $ — $ (2) Net (gain) loss 80 20 (43) Total AOCI $ 79 $ 20 $ (45) Balance at December 31, 2022 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 26 11 (72) Total AOCI $ 24 $ 11 $ (75) Presented below are the amounts included in AOCI at December 31, 2023 and 2022 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Southern Southern Company (in millions) Balance at December 31, 2023 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (10) 1 (10) Total AOCI $ (9) $ 1 $ (10) Balance at December 31, 2022 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (5) — (2) Total AOCI $ (4) $ — $ (2)
Components of OCI related to defined benefit pension plan	The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Southern Southern Company (in millions) AOCI: Balance at December 31, 2021 $ 100 $ 35 $ (45) Net gain (82) (22) (30) Reclassification adjustments: Amortization of net gain (loss) 6 (2) — Total change (76) (24) (30) Balance at December 31, 2022 $ 24 $ 11 $ (75) Net loss 62 9 29 Reclassification adjustments: Amortization of prior service costs 1 — 1 Amortization of net loss (8) — — Total reclassification adjustments (7) — 1 Total change 55 9 30 Balance at December 31, 2023 $ 79 $ 20 $ (45) The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2023 and 2022 are presented in the following table: Southern Company Southern Southern Company Gas (in millions) AOCI: Balance at December 31, 2021 $ — $ 2 $ (5) Net gain (3) (2) — Reclassification adjustments: Amortization of net gain (loss) (1) — 3 Total change (4) (2) 3 Balance at December 31, 2022 $ (4) $ — $ (2) Net (gain) loss (12) 1 — Reclassification adjustments: Amortization of net gain (loss) 7 — (8) Total change (5) 1 (8) Balance at December 31, 2023 $ (9) $ 1 $ (10)
Components of net periodic benefit cost	Components of net periodic pension cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Service cost $ 275 $ 64 $ 68 $ 11 $ 6 $ 24 Interest cost 626 145 191 28 8 42 Expected return on plan assets (1,229) (297) (385) (56) (15) (85) Recognized net (gain) loss 32 9 13 2 — (5) Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (296) $ (78) $ (112) $ (15) $ (1) $ (12) 2022 Service cost $ 412 $ 99 $ 103 $ 17 $ 9 $ 34 Interest cost 408 96 123 18 6 28 Expected return on plan assets (1,265) (306) (399) (57) (15) (91) Recognized net loss 240 62 75 11 2 8 Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (205) $ (48) $ (97) $ (11) $ 2 $ (9) 2021 Service cost $ 434 $ 102 $ 112 $ 18 $ 10 $ 37 Interest cost 346 82 104 16 5 24 Expected return on plan assets (1,191) (287) (375) (55) (14) (86) Recognized net loss 314 82 100 15 3 13 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (96) $ (20) $ (58) $ (6) $ 4 $ — Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2023 Service cost $ 15 $ 4 $ 4 $ 1 $ — $ 1 Interest cost 70 17 25 3 — 9 Expected return on plan assets (83) (33) (29) (3) 1 (10) Net amortization (11) (3) (3) — — 6 Net periodic postretirement benefit cost (income) $ (9) $ (15) $ (3) $ 1 $ 1 $ 6 2022 Service cost $ 23 $ 6 $ 6 $ 1 $ — $ 1 Interest cost 42 10 15 2 — 5 Expected return on plan assets (80) (32) (28) (2) 1 (9) Net amortization (1) — 2 — — 6 Net periodic postretirement benefit cost (income) $ (16) $ (16) $ (5) $ 1 $ 1 $ 3 2021 Service cost $ 24 $ 6 $ 7 $ 1 $ — $ 2 Interest cost 35 9 12 1 — 4 Expected return on plan assets (76) (30) (26) (1) 1 (10) Net amortization 2 — 2 — — 6 Net periodic postretirement benefit cost (income) $ (15) $ (15) $ (5) $ 1 $ 1 $ 2
Estimated pension benefit payments	At December 31, 2023, estimated benefit payments were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit Payments: 2024 $ 748 $ 164 $ 241 $ 33 $ 7 $ 57 2025 776 171 248 34 7 59 2026 801 177 254 36 8 60 2027 822 182 257 37 8 62 2028 840 187 260 38 7 64 2029 to 2033 4,417 988 1,337 201 47 336 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit payments: 2024 $ 111 $ 24 $ 40 $ 5 $ 1 $ 17 2025 109 24 39 5 1 17 2026 108 24 38 5 1 16 2027 108 24 38 5 1 16 2028 108 25 38 4 1 15 2029 to 2033 523 123 188 21 1 64
Changes in the APBO and the fair value of plan assets	Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2023 and 2022 were as follows: 2023 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,441 $ 344 $ 514 $ 59 $ 9 $ 179 Service cost 15 4 4 1 — 1 Interest cost 70 17 25 3 — 9 Benefits paid (107) (24) (36) (4) (1) (18) Actuarial (gain) loss (33) (12) (18) (2) 1 1 Balance at end of year 1,386 329 489 57 9 172 Change in plan assets Fair value of plan assets at beginning of year 998 372 368 24 — 113 Actual return on plan assets 131 52 51 2 — 19 Employer contributions 73 3 27 3 1 14 Benefits paid (107) (24) (36) (4) (1) (18) Fair value of plan assets at end of year 1,095 403 410 25 — 128 Accrued asset (liability) $ (291) $ 74 $ (79) $ (32) $ (9) $ (44) 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,849 $ 440 $ 656 $ 76 $ 11 $ 237 Service cost 23 6 6 1 — 1 Interest cost 42 10 15 2 — 5 Benefits paid (109) (23) (38) (4) (1) (18) Actuarial gain (365) (89) (125) (16) (1) (46) Retiree drug subsidy 1 — — — — — Balance at end of year 1,441 344 514 59 9 179 Change in plan assets Fair value of plan assets at beginning of year 1,251 489 450 29 — 143 Actual loss on plan assets (218) (98) (71) (4) — (25) Employer contributions 73 4 27 3 1 13 Benefits paid (108) (23) (38) (4) (1) (18) Fair value of plan assets at end of year 998 372 368 24 — 113 Accrued asset (liability) $ (443) $ 28 $ (146) $ (35) $ (9) $ (66)
Summary of investment strategies and benefit plan asset fair values	A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below: Description Valuation Methodology Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches. International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches. Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market, but are classified as Level 2. Fixed income: A mix of domestic and international bonds. Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument. Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities. Real estate: Investments in equity or debt of real properties and in publicly traded real estate securities. Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature. Private equity: Investments in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt. Private credit: Investments focused on debt instruments, of which returns are driven by income rather than capital appreciation. Infrastructure: Investments in real assets, typically with long-term, predictable, and stable cash flows and a meaningful income component. Investments in real estate, special situations, private equity, private credit, and infrastructure are typically invested in private partnerships and/or other pooled vehicles (Funds) which are generally classified as Net Asset Value as a Practical Expedient, since the Funds and underlying assets are not publicly traded and/or often have liquidity restrictions. The managers of the Funds value the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The total market value of each of the Funds is determined by aggregating the value of the underlying assets less liabilities.
Fair values of plan assets	The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2023 and 2022 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 41 % 40 % Domestic equity $ 1,959 $ 771 $ — $ — $ 2,730 International equity 1,947 1,052 — — 2,999 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 1,973 — — 1,973 Mortgage- and asset-backed securities — 44 — — 44 Corporate bonds — 1,724 — — 1,724 Pooled funds — 777 — — 777 Cash equivalents and other 371 58 — — 429 Real estate investments 369 — — 1,684 2,053 12 14 Special situations — — — 245 245 3 2 Private equity — — — 1,761 1,761 9 12 Private credit — — — 25 25 3 — Infrastructure — — — — — 2 — Total $ 4,646 $ 6,399 $ — $ 3,715 $ 14,760 100 % 100 % Alabama Power Assets: Equity: 41 % 40 % Domestic equity $ 476 $ 187 $ — $ — $ 663 International equity 472 255 — — 727 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 479 — — 479 Mortgage- and asset-backed securities — 11 — — 11 Corporate bonds — 418 — — 418 Pooled funds — 188 — — 188 Cash equivalents and other 90 14 — — 104 Real estate investments 89 — — 408 497 12 14 Special situations — — — 59 59 3 2 Private equity — — — 427 427 9 12 Private credit — — — 6 6 3 — Infrastructure — — — — — 2 — Total $ 1,127 $ 1,552 $ — $ 900 $ 3,579 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Georgia Power Assets: Equity: 41 % 40 % Domestic equity $ 611 $ 241 $ — $ — $ 852 International equity 609 329 — — 938 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 617 — — 617 Mortgage- and asset-backed securities — 14 — — 14 Corporate bonds — 539 — — 539 Pooled funds — 243 — — 243 Cash equivalents and other 116 18 — — 134 Real estate investments 115 — — 527 642 12 14 Special situations — — — 77 77 3 2 Private equity — — — 551 551 9 12 Private credit — — — 8 8 3 — Infrastructure — — — — — 2 — Total $ 1,451 $ 2,001 $ — $ 1,163 $ 4,615 100 % 100 % Mississippi Power Assets: Equity: 41 % 40 % Domestic equity $ 89 $ 35 $ — $ — $ 124 International equity 89 48 — — 137 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 90 — — 90 Mortgage- and asset-backed securities — 2 — — 2 Corporate bonds — 79 — — 79 Pooled funds — 36 — — 36 Cash equivalents and other 17 3 — — 20 Real estate investments 17 — — 77 94 12 14 Special situations — — — 11 11 3 2 Private equity — — — 81 81 9 12 Private credit — — — 1 1 3 — Infrastructure — — — — — 2 — Total $ 212 $ 293 $ — $ 170 $ 675 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Power Assets: Equity: 41 % 40 % Domestic equity $ 24 $ 10 $ — $ — $ 34 International equity 25 13 — — 38 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 25 — — 25 Mortgage- and asset-backed securities — 1 — — 1 Corporate bonds — 22 — — 22 Pooled funds — 10 — — 10 Cash equivalents and other 5 1 — — 6 Real estate investments 5 — — 21 26 12 14 Special situations — — — 3 3 3 2 Private equity — — — 22 22 9 12 Private credit — — — — — 3 — Infrastructure — — — — — 2 — Total $ 59 $ 82 $ — $ 46 $ 187 100% 100 % Southern Company Gas Assets: Equity: 41 % 40 % Domestic equity $ 130 $ 52 $ — $ — $ 182 International equity 130 71 — — 201 Fixed income: 30 32 U.S. Treasury, government, and agency bonds — 132 — — 132 Mortgage- and asset-backed securities — 3 — — 3 Corporate bonds — 116 — — 116 Pooled funds — 52 — — 52 Cash equivalents and other 25 4 — — 29 Real estate investments 25 — — 113 138 12 14 Special situations — — — 16 16 3 2 Private equity — — — 118 118 9 12 Private credit — — — 2 2 3 — Infrastructure — — — — — 2 — Total $ 310 $ 430 $ — $ 249 $ 989 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 45 % 43 % Domestic equity $ 2,078 $ 691 $ — $ — $ 2,769 International equity 2,166 1,090 — — 3,256 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 1,469 — — 1,469 Mortgage- and asset-backed securities — 29 — — 29 Corporate bonds — 1,494 — — 1,494 Pooled funds — 607 — — 607 Cash equivalents and other 399 7 — — 406 Real estate investments 376 — — 1,887 2,263 13 15 Special situations — — — 187 187 3 2 Private equity — — — 1,717 1,717 9 12 Total $ 5,019 $ 5,387 $ — $ 3,791 $ 14,197 100 % 100 % Liabilities: Derivatives (4) — — — (4) Total $ 5,015 $ 5,387 $ — $ 3,791 $ 14,193 100 % 100 % Alabama Power Assets: Equity: 45 % 43 % Domestic equity $ 500 $ 167 $ — $ — $ 667 International equity 522 263 — — 785 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 354 — — 354 Mortgage- and asset-backed securities — 7 — — 7 Corporate bonds — 360 — — 360 Pooled funds — 146 — — 146 Cash equivalents and other 96 2 — — 98 Real estate investments 91 — — 455 546 13 15 Special situations — — — 45 45 3 2 Private equity — — — 414 414 9 12 Total $ 1,209 $ 1,299 $ — $ 914 $ 3,422 100 % 100 % Liabilities: Derivatives (1) — — — (1) Total $ 1,208 $ 1,299 $ — $ 914 $ 3,421 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Georgia Power Assets: Equity: 45 % 43 % Domestic equity $ 651 $ 217 $ — $ — $ 868 International equity 678 342 — — 1,020 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 460 — — 460 Mortgage- and asset-backed securities — 9 — — 9 Corporate bonds — 468 — — 468 Pooled funds — 190 — — 190 Cash equivalents and other 125 2 — — 127 Real estate investments 118 — — 591 709 13 15 Special situations — — — 59 59 3 2 Private equity — — — 538 538 9 12 Total $ 1,572 $ 1,688 $ — $ 1,188 $ 4,448 100 % 100 % Liabilities: Derivatives (1) — — — (1) Total $ 1,571 $ 1,688 $ — $ 1,188 $ 4,447 100 % 100 % Mississippi Power Assets: Equity: 45 % 43 % Domestic equity $ 95 $ 32 $ — $ — $ 127 International equity 99 50 — — 149 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 67 — — 67 Mortgage- and asset-backed securities — 1 — — 1 Corporate bonds — 68 — — 68 Pooled funds — 28 — — 28 Cash equivalents and other 18 — — — 18 Real estate investments 17 — — 86 103 13 15 Special situations — — — 9 9 3 2 Private equity — — — 78 78 9 12 Total $ 229 $ 246 $ — $ 173 $ 648 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Power Assets: Equity: 45 % 43 % Domestic equity $ 25 $ 9 $ — $ — $ 34 International equity 27 14 — — 41 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 18 — — 18 Corporate bonds — 19 — — 19 Pooled funds — 8 — — 8 Cash equivalents and other 5 — — — 5 Real estate investments 5 — — 24 29 13 15 Special situations — — — 2 2 3 2 Private equity — — — 21 21 9 12 Total $ 62 $ 68 $ — $ 47 $ 177 100 % 100 % Southern Company Gas Assets: Equity: 45 % 43 % Domestic equity $ 146 $ 49 $ — $ — $ 195 International equity 152 77 — — 229 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 104 — — 104 Mortgage- and asset-backed securities — 2 — — 2 Corporate bonds — 105 — — 105 Pooled funds — 43 — — 43 Cash equivalents and other 28 1 — — 29 Real estate investments 27 — — 133 160 13 15 Special situations — — — 13 13 3 2 Private equity — — — 121 121 9 12 Total $ 353 $ 381 $ — $ 267 $ 1,001 100 % 100 % The fair values, and actual allocations relative to the target allocations, of the applicable Registrants' other postretirement benefit plan assets at December 31, 2023 and 2022 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (NAV) (in millions) Southern Company Assets: Equity: 60 % 61 % Domestic equity $ 85 $ 87 $ — $ 172 International equity 53 82 — 135 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 57 — 57 Mortgage- and asset-backed securities — 2 — 2 Corporate bonds — 47 — 47 Pooled funds — 92 — 92 Cash equivalents and other 21 2 — 23 Trust-owned life insurance — 456 — 456 Real estate investments 11 — 46 57 4 6 Special situations — — 6 6 1 1 Private equity — — 48 48 3 4 Private credit — — 1 1 1 — Infrastructure — — — — 1 — Total $ 170 $ 825 $ 101 $ 1,096 100 % 100 % Alabama Power Assets: Equity: 67 % 66 % Domestic equity $ 16 $ 6 $ — $ 22 International equity 16 9 — 25 Fixed income: 23 23 U.S. Treasury, government, and agency bonds — 16 — 16 Corporate bonds — 14 — 14 Pooled funds — 8 — 8 Cash equivalents and other 3 — — 3 Trust-owned life insurance — 280 — 280 Real estate investments 3 — 14 17 4 6 Special situations — — 2 2 1 1 Private equity — — 15 15 3 4 Private credit — — — — 1 — Infrastructure — — — — 1 — Total $ 38 $ 333 $ 31 $ 402 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (NAV) (in millions) Georgia Power Assets: Equity: 58 % 57 % Domestic equity $ 47 $ 6 $ — $ 53 International equity 16 40 — 56 Fixed income: 35 35 U.S. Treasury, government, and agency bonds — 16 — 16 Corporate bonds — 14 — 14 Pooled funds — 47 — 47 Cash equivalents and other 13 — — 13 Trust-owned life insurance — 176 — 176 Real estate investments 4 — 14 18 3 4 Special situations — — 2 2 1 1 Private equity — — 14 14 2 3 Private credit — — — — 1 — Infrastructure — — — — — — Total $ 80 $ 299 $ 30 $ 409 100 % 100 % Mississippi Power Assets: Equity: 34 % 33 % Domestic equity $ 3 $ 1 $ — $ 4 International equity 3 1 — 4 Fixed income: 43 44 U.S. Treasury, government, and agency bonds — 7 — 7 Corporate bonds — 2 — 2 Pooled funds — 1 — 1 Cash equivalents and other 1 — — 1 Real estate investments 1 — 2 3 10 11 Special situations — — — — 2 2 Private equity — — 2 2 7 10 Private credit — — — — 3 — Infrastructure — — — — 1 — Total $ 8 $ 12 $ 4 $ 24 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2023: (Level 1) (Level 2) (NAV) (in millions) Southern Company Gas Assets: Equity: 72 % 72 % Domestic equity $ 2 $ 67 $ — $ 69 International equity 2 22 — 24 Fixed income: 26 26 U.S. Treasury, government, and agency bonds — 1 — 1 Corporate bonds — 1 — 1 Pooled funds — 29 — 29 Cash equivalents and other 1 — — 1 Trust-owned life insurance — — — — Real estate investments — — 1 1 1 1 Private equity — — 1 1 1 1 Total $ 5 $ 120 $ 2 $ 127 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) Total (in millions) Southern Company Assets: Equity: 61 % 59 % Domestic equity $ 85 $ 74 $ — $ 159 International equity 58 79 — 137 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 43 — 43 Mortgage- and asset-backed securities — 1 — 1 Corporate bonds — 40 — 40 Pooled funds — 79 — 79 Cash equivalents and other 19 — — 19 Trust-owned life insurance — 406 — 406 Real estate investments 11 — 51 62 5 7 Special situations — — 6 6 1 1 Private equity — — 46 46 3 5 Total $ 173 $ 722 $ 103 $ 998 100 % 100 % Alabama Power Assets: Equity: 69 % 65 % Domestic equity $ 17 $ 6 $ — $ 23 International equity 18 9 — 27 Fixed income: 23 23 U.S. Treasury, government, and agency bonds — 12 — 12 Corporate bonds — 12 — 12 Pooled funds — 7 — 7 Cash equivalents and other 3 — — 3 Trust-owned life insurance — 252 — 252 Real estate investments 3 — 16 19 4 7 Special situations — — 2 2 1 1 Private equity — — 14 14 3 4 Total $ 41 $ 298 $ 32 $ 371 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) Total (in millions) Georgia Power Assets: Equity: 58 % 56 % Domestic equity $ 46 $ 6 $ — $ 52 International equity 17 39 — 56 Fixed income: 35 34 U.S. Treasury, government, and agency bonds — 10 — 10 Corporate bonds — 12 — 12 Pooled funds — 40 — 40 Cash equivalents and other 9 — — 9 Trust-owned life insurance — 154 — 154 Real estate investments 4 — 15 19 4 5 Special situations — — 2 2 1 1 Private equity — — 14 14 2 4 Total $ 76 $ 261 $ 31 $ 368 100 % 100 % Mississippi Power Assets: Equity: 37 % 35 % Domestic equity $ 3 $ 1 $ — $ 4 International equity 3 2 — 5 Fixed income: 43 41 U.S. Treasury, government, and agency bonds — 4 — 4 Corporate bonds — 2 — 2 Pooled funds — 1 — 1 Cash equivalents and other 2 — — 2 Real estate investments 1 — 3 4 11 12 Special situations — — — — 2 2 Private equity — — 2 2 7 10 Total $ 9 $ 10 $ 5 $ 24 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) Total (in millions) Southern Company Gas Assets: Equity: 72 % 70 % Domestic equity $ 2 $ 56 $ — $ 58 International equity 2 20 — 22 Fixed income: 26 27 U.S. Treasury, government, and agency bonds — 1 — 1 Corporate bonds — 1 — 1 Pooled funds — 27 — 27 Cash equivalents and other 1 — — 1 Real estate investments — — 2 2 1 2 Private equity — — 1 1 1 1 Total $ 5 $ 105 $ 3 $ 113 100 % 100 %
Total matching contributions	Total matching contributions made to the plans for 2023, 2022, and 2021 were as follows: Southern Company Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2023 $ 131 $ 28 $ 31 $ 5 $ 3 $ 18 2022 124 26 29 5 3 17 2021 119 26 28 5 2 16

STOCK COMPENSATION (Tables)

STOCK COMPENSATION (Tables)	12 Months Ended
STOCK COMPENSATION (Tables)	Dec. 31, 2023
Share-Based Payment Arrangement [Abstract]
Schedule of employees participating in stock-based compensation programs	At December 31, 2023, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Number of employees 1,401 191 210 42 40 193
Assumptions used in the pricing model and the weighted average grant-date fair value of performance share award units granted	The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted: Year Ended December 31 2023 2022 2021 Expected volatility 30.0% 29.6% 30.0% Expected term (in years) 3 3 3 Interest rate 3.8% 1.7% 0.2% Weighted average grant-date fair value $76.83 $79.69 $69.06
Schedule of compensation costs and related tax benefits	Total PSU compensation cost, and the related tax benefit recognized in income, for the years ended December 31, 2023, 2022, and 2021 are as follows: 2023 2022 2021 (in millions) Southern Company Compensation cost recognized in income $ 107 $ 101 $ 112 Tax benefit of compensation cost recognized in income 28 26 29 Southern Company Gas Compensation cost recognized in income $ 14 $ 12 $ 17 Tax benefit of compensation cost recognized in income 4 4 4 Total intrinsic value of options exercised, and the related tax benefit, for the years ended December 31, 2023, 2022, and 2021 are presented below for Southern Company and were immaterial for all other Registrants: Year Ended December 31 2023 2022 2021 (in millions) Southern Company Intrinsic value of options exercised $ 18 $ 49 $ 34 Tax benefit of options exercised 4 12 7
Share-based compensation, stock options, activity	Southern Company's activity in the stock option program for 2023 is summarized below: Shares Subject to Option Weighted Average Exercise Price (in millions) Outstanding at December 31, 2022 1.0 $ 42.22 Exercised 0.7 42.54 Outstanding and Exercisable at December 31, 2023 0.3 $ 41.58

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
FAIR VALUE MEASUREMENTS (Tables)	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis	The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2023, 2022, and 2021 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2023 $ 281 $ 157 $ 124 2022 (360) (171) (189) 2021 274 200 74 Unrealized gains (losses) At December 31, 2023 $ 241 $ 119 $ 122 At December 31, 2022 (391) (204) (187) At December 31, 2021 (27) (30) 3 At December 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 6 $ 49 $ — $ — $ 55 Investments in trusts: (b) Domestic equity 764 216 — — 980 Foreign equity 145 171 — — 316 U.S. Treasury and government agency securities — 369 — — 369 Municipal bonds — 48 — — 48 Pooled funds – fixed income — 6 — — 6 Corporate bonds — 389 — — 389 Mortgage and asset backed securities — 89 — — 89 Private equity — — — 169 169 Cash and cash equivalents 3 — — — 3 Other 58 3 — 9 70 Cash equivalents and restricted cash 253 15 — — 268 Other investments 9 27 8 — 44 Total $ 1,238 $ 1,382 $ 8 $ 178 $ 2,806 Liabilities: Energy-related derivatives (a) $ 46 $ 312 $ — $ — $ 358 Interest rate derivatives — 264 — — 264 Foreign currency derivatives — 122 — — 122 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 49 $ 711 $ 16 $ — $ 776 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Nuclear decommissioning trusts: (b) Domestic equity 443 208 — — 651 Foreign equity 145 — — — 145 U.S. Treasury and government agency securities — 20 — — 20 Municipal bonds — 1 — — 1 Corporate bonds — 231 — — 231 Mortgage and asset backed securities — 25 — — 25 Private equity — — — 169 169 Other 8 — — 9 17 Cash equivalents and restricted cash 119 15 — — 134 Other investments — 27 — — 27 Total $ 715 $ 542 $ — $ 178 $ 1,435 Liabilities: Energy-related derivatives $ — $ 110 $ — $ — $ 110 Georgia Power Assets: Energy-related derivatives $ — $ 13 $ — $ — $ 13 Nuclear decommissioning trusts: (b) Domestic equity 321 1 — — 322 Foreign equity — 170 — — 170 U.S. Treasury and government agency securities — 349 — — 349 Municipal bonds — 47 — — 47 Corporate bonds — 158 — — 158 Mortgage and asset backed securities — 64 — — 64 Other 50 3 — — 53 Total $ 371 $ 805 $ — $ — $ 1,176 Liabilities: Energy-related derivatives $ — $ 124 $ — $ — $ 124 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2023: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 15 $ — $ — $ 15 Cash equivalents 17 — — — 17 Total $ 17 $ 15 $ — $ — $ 32 Liabilities: Energy-related derivatives $ — $ 61 $ — $ — $ 61 Southern Power Assets: Energy-related derivatives $ — $ 3 $ — $ — $ 3 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Foreign currency derivatives — 22 — — 22 Contingent consideration 3 — 16 — 19 Other — 13 — — 13 Total $ 3 $ 40 $ 16 $ — $ 59 Southern Company Gas Assets: Energy-related derivatives (a) $ 6 $ 3 $ — $ — $ 9 Non-qualified deferred compensation trusts: Domestic equity — 7 — — 7 Foreign equity — 1 — — 1 Pooled funds - fixed income — 6 — — 6 Cash and cash equivalents 3 — — — 3 Total $ 9 $ 17 $ — $ — $ 26 Liabilities: Energy-related derivatives (a)(b) $ 46 $ 12 $ — $ — $ 58 Interest rate derivatives — 79 — — 79 Total $ 46 $ 91 $ — $ — $ 137 (a) Excludes cash collateral of $62 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information.
Financial instruments not having carrying amount equal to fair value	At December 31, 2023 and 2022, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company () Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas () (in billions) At December 31, 2023: Long-term debt, including securities due within one year: Carrying amount $ 59.4 $ 11.2 $ 16.5 $ 1.6 $ 2.7 $ 7.8 Fair value 55.0 10.1 15.1 1.4 2.6 6.8 At December 31, 2022: Long-term debt, including securities due within one year: Carrying amount $ 54.6 $ 10.6 $ 14.7 $ 1.5 $ 3.0 $ 7.4 Fair value 48.6 9.2 13.0 1.3 2.8 6.5 (*) The carrying amount of Southern Company Gas' long-term debt includes fair value adjustments from the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043.

DERIVATIVES (Tables)

DERIVATIVES (Tables)	12 Months Ended
DERIVATIVES (Tables)	Dec. 31, 2023
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of energy-related derivatives	At December 31, 2023, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows: Net Longest Longest (in millions) Southern Company () 448 2030 2028 Alabama Power 118 2026 — Georgia Power 128 2026 — Mississippi Power 93 2028 — Southern Power 7 2030 2024 Southern Company Gas () 102 2027 2028 (*) Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 112 million mmBtu and short natural gas positions of 10 million mmBtu at December 31, 2023, which is also included in Southern Company's total volume.
Notional amount of interest rate derivatives	At December 31, 2023, the following interest rate derivatives were outstanding: Notional Weighted Average Interest Rate Paid Interest Hedge Fair Value (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 150 4.01% N/A April 2024 $ — Mississippi Power 75 3.84% N/A June 2024 — Mississippi Power 75 4.04% N/A June 2024 — Fair Value Hedges of Existing Debt Southern Company parent 400 1-month SOFR + 0.80% 1.75% March 2028 (46) Southern Company parent 1,000 1-month SOFR + 2.48% 3.70% April 2030 (139) Southern Company Gas 500 1-month SOFR + 0.49% 1.75% January 2031 (79) Southern Company $ 2,200 $ (264)
Schedule of foreign exchange contracts	At December 31, 2023, the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 564 3.78% € 500 1.85% June 2026 $ (22) Fair Value Hedges of Existing Debt Southern Company parent 1,476 3.39% 1,250 1.88% September 2027 (100) Southern Company $ 2,040 € 1,750 $ (122)
Fair value of energy-related derivatives and interest rate derivatives	The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Company Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Liabilities from risk management activities $ 12 $ 198 $ 123 $ 121 Other deferred charges and assets/Other deferred credits and liabilities 31 117 52 44 Total derivatives designated as hedging instruments for regulatory purposes 43 315 175 165 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities — 29 3 27 Other deferred charges and assets/Other deferred credits and liabilities 3 4 6 4 Interest rate derivatives: Assets from risk management activities/Liabilities from risk management activities — 74 12 62 Other deferred charges and assets/Other deferred credits and liabilities — 190 — 240 Foreign currency derivatives: Assets from risk management activities/Liabilities from risk management activities — 34 — 34 Other deferred charges and assets/Other deferred credits and liabilities — 88 — 182 Total derivatives designated as hedging instruments in cash flow and fair value hedges 3 419 21 549 Energy-related derivatives not designated as hedging instruments Assets from risk management activities/Liabilities from risk management activities 8 8 13 13 Other deferred charges and assets/Other deferred credits and liabilities 1 2 2 1 Total derivatives not designated as hedging instruments 9 10 15 14 Gross amounts recognized 55 744 211 728 Gross amounts offset (a) (23) (85) (70) (111) Net amounts recognized in the Balance Sheets (b) $ 32 $ 659 $ 141 $ 617 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Alabama Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 6 $ 69 $ 42 $ 21 Other deferred charges and assets/Other deferred credits and liabilities 9 41 20 18 Total derivatives designated as hedging instruments for regulatory purposes 15 110 62 39 Gross amounts offset (10) (10) (24) (24) Net amounts recognized in the Balance Sheets $ 5 $ 100 $ 38 $ 15 Georgia Power Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 2 $ 82 $ 36 $ 43 Other deferred charges and assets/Other deferred credits and liabilities 10 42 6 18 Total derivatives designated as hedging instruments for regulatory purposes 12 124 42 61 Energy-related derivatives not designated as hedging instruments Other deferred charges and assets/Other deferred credits and liabilities 1 — — 1 Gross amounts recognized 13 124 42 62 Gross amounts offset (11) (11) (21) (21) Net amounts recognized in the Balance Sheets $ 2 $ 113 $ 21 $ 41 Mississippi Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 3 $ 27 $ 33 $ 24 Other deferred charges and assets/Other deferred credits and liabilities 12 34 26 8 Total derivatives designated as hedging instruments for regulatory purposes 15 61 59 32 Gross amounts offset (14) (14) (17) (17) Net amounts recognized in the Balance Sheets $ 1 $ 47 $ 42 $ 15 2023 2022 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ — $ 5 $ — $ 12 Other deferred charges and assets/Other deferred credits and liabilities 3 — 5 — Foreign currency derivatives: Other current assets/Other current liabilities — 11 — 11 Other deferred charges and assets/Other deferred credits and liabilities — 11 — 36 Total derivatives designated as hedging instruments in cash flow and fair value hedges 3 27 5 59 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities — — 2 — Other deferred charges and assets/Other deferred credits and liabilities — — 1 — Total derivatives not designated as hedging instruments — — 3 — Net amounts recognized in the Balance Sheets $ 3 $ 27 $ 8 $ 59 Southern Company Gas Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 1 $ 20 $ 12 $ 33 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities — 24 3 15 Other deferred charges and assets/Other deferred credits and liabilities — 4 1 4 Interest rate derivatives: Other current assets/Other current liabilities — 20 — 14 Other deferred charges and assets/Other deferred credits and liabilities — 59 — 72 Total derivatives designated as hedging instruments in cash flow and fair value hedges — 107 4 105 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 7 8 11 12 Other deferred charges and assets/Other deferred credits and liabilities 1 2 1 1 Total derivatives not designated as hedging instruments 8 10 12 13 Gross amounts recognized 9 137 28 151 Gross amounts offset (a) 12 (50) — (41) Net amounts recognized in the Balance Sheets (b) $ 21 $ 87 $ 28 $ 110 (a) Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $62 million and $41 million at December 31, 2023 and 2022, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented. (c) Energy-related derivatives not designated as hedging instruments were immaterial at December 31, 2022. There were no such instruments at December 31, 2023.
Pre-tax effects on the balance sheets	At December 31, 2023 and 2022, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows: Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At December 31, 2023: Energy-related derivatives: Other regulatory assets, current $ (180) $ (67) $ (80) $ (25) $ (8) Other regulatory assets, deferred (87) (32) (33) (22) — Other regulatory liabilities, current 9 4 — 1 4 Other regulatory liabilities, deferred 1 — 1 — — Total energy-related derivative gains (losses) $ (257) $ (95) $ (112) $ (46) $ (4) At December 31, 2022: Energy-related derivatives: Other regulatory assets, current $ (71) $ (8) $ (26) $ (13) $ (24) Other regulatory assets, deferred (23) (7) (14) (2) — Other regulatory liabilities, current 72 29 19 22 2 Other regulatory liabilities, deferred 31 9 2 20 — Total energy-related derivative gains (losses) $ 9 $ 23 $ (19) $ 27 $ (22)
Pre-tax effects of hedging on AOCI	For the years ended December 31, 2023, 2022, and 2021, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows: Gain (Loss) From Derivatives Recognized in OCI 2023 2022 2021 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ (81) $ 3 $ 34 Interest rate derivatives (12) 46 5 Foreign currency derivatives 14 (105) (103) Fair value hedges () : Foreign currency derivatives 21 (24) (3) Total $ (58) $ (80) $ (67) Georgia Power Cash flow hedges: Interest rate derivatives $ (2) $ 31 $ — Southern Power Cash flow hedges: Energy-related derivatives $ (18) $ (15) $ 12 Foreign currency derivatives 14 (105) (103) Total $ (4) $ (120) $ (91) Southern Company Gas Cash flow hedges: Energy-related derivatives $ (63) $ 18 $ 22 () Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
Pre-tax effect of interest rate and energy related derivatives	The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2023, 2022, and 2021 were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships 2023 2022 2021 (in millions) Southern Company Total cost of natural gas $ 1,644 $ 3,004 $ 1,619 Gain (loss) on energy-related cash flow hedges (a) (44) 37 17 Total other operations and maintenance 6,093 6,573 5,902 Gain (loss) on energy-related cash flow hedges (a) (2) — — Total depreciation and amortization 4,525 3,663 3,565 Gain (loss) on energy-related cash flow hedges (a) (23) (5) 9 Total interest expense, net of amounts capitalized (2,446) (2,022) (1,837) Gain (loss) on interest rate cash flow hedges (a) (35) (25) (27) Gain (loss) on foreign currency cash flow hedges (a) (11) (19) (24) Gain (loss) on interest rate fair value hedges (b) 37 (291) (30) Total other income (expense), net 553 500 449 Gain (loss) on foreign currency cash flow hedges (a)(c) 19 (83) (104) Gain (loss) on foreign currency fair value hedges 69 (106) (63) Amount excluded from effectiveness testing recognized in earnings (21) 24 3 Southern Power Total depreciation and amortization $ 504 $ 516 $ 517 Gain (loss) on energy-related cash flow hedges (a) (23) (5) 9 Total interest expense, net of amounts capitalized (129) (138) (147) Gain (loss) on foreign currency cash flow hedges (a) (11) (19) (24) Total other income (expense), net 12 7 10 Gain (loss) on foreign currency cash flow hedges (a)(c) 19 (83) (104) Southern Company Gas Total cost of natural gas $ 1,644 $ 3,004 $ 1,619 Gain (loss) on energy-related cash flow hedges (a) (44) 37 17 Total other operations and maintenance 1,194 1,176 1,072 Gain (loss) on energy-related cash flow hedges (a) (2) — — Total interest expense, net of amounts capitalized (310) (263) (238) Gain (loss) on interest rate cash flow hedges (a) (19) (4) — Gain (loss) on interest rate fair value hedges (b) 6 (86) — (a) Reclassified from AOCI into earnings. (b) For fair value hedges, changes in the fair value of the derivative contracts are generally equal to changes in the fair value of the underlying debt and have no material impact on income. (c) The reclassification from AOCI into other income (expense), net completely offsets currency gains and losses arising from changes in the U.S. currency exchange rates used to record the euro-denominated notes.
Schedule of fair value hedging instruments, statements of financial performance and financial position, location	At December 31, 2023 and 2022, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At December 31, 2023 At December 31, 2022 At December 31, 2023 At December 31, 2022 (in millions) (in millions) Southern Company Long-term debt $ (3,024) $ (2,927) $ 235 $ 282 Southern Company Gas Long-term debt $ (427) $ (415) $ 70 $ 81
Pre-tax effect of interest rate and energy related derivatives	The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2023, 2022, and 2021 were as follows: Gain (Loss) Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2023 2022 2021 (in millions) Energy-related derivatives Natural gas revenues () $ — $ (11) $ (117) Cost of natural gas 59 (65) (27) Total derivatives in non-designated hedging relationships $ 59 $ (76) $ (144) () Excludes the impact of weather derivatives recorded in natural gas revenues of $15 million and $(7) million for 2023 and 2022, respectively, as they are accounted for based on intrinsic value rather than fair value. There was no weather derivatives impact for 2021.

ACQUISITIONS AND DISPOSITIONS (

ACQUISITIONS AND DISPOSITIONS (Tables)	12 Months Ended
ACQUISITIONS AND DISPOSITIONS (Tables)	Dec. 31, 2023
Business Combination and Asset Acquisition [Abstract]
Schedule of asset acquisition	Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern Expected/Actual COD PPA Asset Acquisitions During 2023 Millers Branch (a) Solar EDF Renewables Development, Inc. 200 Haskell County, TX 100% Fourth quarter 2025 20 years South Cheyenne Solar Hanwha Q Cells USA Corp. 150 Laramie County, WY 100% Second quarter 2024 20 years Asset Acquisitions During 2021 Deuel Harvest (b) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years (a) The project includes an option to expand capacity up to an additional 300 MWs. Subsequent to December 31, 2023, Southern Power committed to expand the construction of the facility through a second phase adding up to 205 MWs, with commercial operation expected to occur in the second quarter 2026. (b) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest.
Schedule of construction projects	Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years (a) In 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. See Note 9 under "Lessor" for additional information. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility.

SEGMENT AND RELATED INFORMATI_2

SEGMENT AND RELATED INFORMATION (Tables)	12 Months Ended
SEGMENT AND RELATED INFORMATION (Tables)	Dec. 31, 2023
Segment Reporting [Abstract]
Financial data for business segments	Financial data for business segments and products and services for the years ended December 31, 2023, 2022, and 2021 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) 2023 Operating revenues $ 18,358 $ 2,189 $ (549) $ 19,998 $ 4,702 $ 718 $ (165) $ 25,253 Depreciation and amortization 3,361 504 — 3,865 582 78 — 4,525 Interest income 69 7 — 76 9 26 (26) 85 Earnings from equity method investments (1) — — (1) 140 5 — 144 Interest expense 1,145 129 — 1,274 310 879 (17) 2,446 Income taxes (benefit) 571 12 — 583 211 (298) — 496 Segment net income (loss) (a)(b)(c)(d) 3,637 357 — 3,994 615 (635) 2 3,976 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 100,429 12,761 (545) 112,645 25,083 2,446 (843) 139,331 2022 Operating revenues $ 20,408 $ 3,369 $ (904) $ 22,873 $ 5,962 $ 593 $ (149) $ 29,279 Depreciation and amortization 2,513 516 — 3,029 559 75 — 3,663 Interest income 44 3 — 47 3 16 (7) 59 Earnings from equity method investments — — — — 148 3 — 151 Interest expense 929 138 — 1,067 263 694 (2) 2,022 Income taxes (benefit) 828 20 — 848 180 (233) — 795 Segment net income (loss) (a)(b)(e)(f) 3,318 354 — 3,672 572 (711) (9) 3,524 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 95,861 13,081 (659) 108,283 24,621 2,665 (678) 134,891 2021 Operating revenues $ 16,614 $ 2,216 $ (530) $ 18,300 $ 4,380 $ 582 $ (149) $ 23,113 Depreciation and amortization 2,436 517 — 2,953 536 76 — 3,565 Interest income 20 1 — 21 — 4 (3) 22 Earnings from equity method investments 1 — — 1 50 24 1 76 Interest expense 821 147 — 968 238 631 — 1,837 Income taxes (benefit) 232 (13) — 219 275 (227) — 267 Segment net income (loss) (a)(b)(g)(h)(i) 1,981 266 — 2,247 539 (384) (9) 2,393 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes pre-tax charges (credits) to income at Georgia Power for the estimated probable loss associated with the construction of Plant Vogtle Units 3 and 4 of $(68) million ($(50) million after tax) in 2023, $183 million ($137 million after tax) in 2022, and $1.7 billion ($1.3 billion after tax) in 2021. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (c) For Southern Power, includes an $18 million pre-tax loss recovery ($9 million after tax and partnership allocations) related to an arbitration award and a $16 million pre-tax gain ($12 million after tax) on the sale of spare parts. See Note 3 under "General Litigation Matters – Southern Power" for additional information. (d) For Southern Company Gas, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information. (e) For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (f) For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets" for additional information. (g) For Southern Power, includes gains on wind turbine equipment contributed to various equity method investments totaling approximately $37 million pre-tax ($28 million after tax). See Notes 7 and 15 under "Southern Power" for additional information. (h) For Southern Company Gas, includes a pre-tax gain of $121 million ($92 million after tax) related to its sale of Sequent, as well as the resulting $85 million of additional tax expense due to changes in state apportionment rates, and pre-tax impairment charges totaling $84 million ($67 million after tax) related to its equity method investment in the PennEast Pipeline project. See Notes 7 and 15 under "Southern Company Gas" for additional information. (i) For the "All Other" column, includes a pre-tax gain of $93 million ($99 million gain after tax) associated with the termination of two leveraged leases projects. See Note 15 under "Southern Company" for additional information. Financial data for business segments for the years ended December 31, 2023, 2022, and 2021 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (a) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) 2023 Operating revenues $ 4,105 $ 32 $ — $ 548 $ 4,685 $ 36 $ (19) $ 4,702 Depreciation and amortization 561 5 — 15 581 1 — 582 Operating income (loss) 804 22 — 130 956 (4) (13) 939 Earnings from equity method investments — 140 — — 140 — — 140 Interest expense 275 32 3 310 — — 310 Income taxes 126 32 — 37 195 16 — 211 Segment net income (loss) (b) 441 98 — 91 630 (15) — 615 Total assets 22,906 1,534 — 1,615 26,055 9,675 (10,647) 25,083 2022 Operating revenues $ 5,267 $ 32 $ — $ 638 $ 5,937 $ 55 $ (30) $ 5,962 Depreciation and amortization 516 5 — 16 537 22 — 559 Operating income (loss) 803 21 — 133 957 (135) (8) 814 Earnings from equity method investments — 148 — — 148 — — 148 Interest expense 229 27 — 3 259 4 — 263 Income taxes (benefit) 145 35 — 37 217 (37) — 180 Segment net income (loss) (c) 470 107 — 94 671 (99) — 572 Total assets 22,040 1,577 — 1,616 25,233 8,943 (9,555) 24,621 2021 Operating revenues $ 3,679 $ 32 $ 188 $ 475 $ 4,374 $ 38 $ (32) $ 4,380 Depreciation and amortization 482 5 — 18 505 31 — 536 Operating income (loss) 708 21 241 125 1,095 (40) — 1,055 Earnings from equity method investments — 50 — — 50 — — 50 Interest expense 207 25 2 3 237 1 — 238 Income taxes 120 27 32 34 213 62 — 275 Segment net income (loss) (d)(e)(f) 412 19 107 88 626 (87) — 539 Total assets 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 (a) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment in 2023 or 2022. Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188 (b) For gas distribution operations, includes pre-tax charges totaling approximately $96 million ($72 million after tax) associated with the disallowance of certain capital investments at Nicor Gas. See Note 2 under "Southern Company Gas" for additional information. (c) For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (d) For gas pipeline investments, includes pre-tax impairment charges totaling $84 million ($67 million after tax) related to the equity method investment in the PennEast Pipeline project. See Note 7 under "Southern Company Gas" for additional information. (e) For wholesale gas services, includes a pre-tax gain of $121 million ($92 million after tax) related to the sale of Sequent. (f) For the "All Other" column, includes $85 million of additional tax expense as a result of the sale of Sequent.
Financial data for products and services	Products and Services Electric Utilities' Revenues Year Retail Wholesale Other Total (in millions) 2023 $ 16,343 $ 2,467 $ 1,188 $ 19,998 2022 18,197 3,641 1,035 22,873 2021 14,852 2,455 993 18,300 Southern Company Gas' Revenues Year Gas Gas All Other Total (in millions) 2023 $ 4,090 $ 548 $ 64 $ 4,702 2022 5,240 638 84 5,962 2021 3,656 475 249 4,380
Schedule of reconciliation of operating revenues and intercompany revenues	A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - General (Narrative) (Details)	Dec. 31, 2023 state company
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of traditional electric operating companies \| company	3
Traditional Electric Operating Companies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of states in which entity provides utilities \| state	3

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Costs for Affiliate Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Alabama Power \| Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	$ 611	$ 549	$ 504
Alabama Power \| Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	12	18	14
Georgia Power \| Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	857	762	663
Georgia Power \| Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	101	99	108
Mississippi Power \| Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	113	115	120
Mississippi Power \| Alabama Power \| Power Pool
Related Party Transaction [Line Items]
Costs for services	4	4	9
Southern Power \| Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	86	86	89
Southern Power \| Alabama Power \| Power Pool
Related Party Transaction [Line Items]
Costs for services	13	29	15
Southern Power \| Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	34	37	31
Southern Company Gas \| Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	261	262	239
Southern Company Gas \| Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	$ 28	$ 27	$ 29

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Affiliate Transactions (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Southern Nuclear Operating Company, Inc. \| Alabama Power
Related Party Transaction [Line Items]
Costs for services	$ 251	$ 267	$ 258
Southern Nuclear Operating Company, Inc. \| Georgia Power
Related Party Transaction [Line Items]
Costs for services	899	895	906
Southern Power \| Georgia Power
Related Party Transaction [Line Items]
Costs for services	143	151	132
Southern Natural Gas Company, LLC \| Alabama Power
Related Party Transaction [Line Items]
Costs for services	12	18	14
Southern Natural Gas Company, LLC \| Georgia Power
Related Party Transaction [Line Items]
Costs for services	101	99	108
Southern Natural Gas Company, LLC \| Southern Power
Related Party Transaction [Line Items]
Costs for services	34	37	31
Southern Natural Gas Company, LLC \| Southern Company Gas
Related Party Transaction [Line Items]
Costs for services	28	27	29
Southern Company Gas \| Southern Power
Related Party Transaction [Line Items]
Costs for services	0	0	18
Southern Company Services, Inc. \| Alabama Power
Related Party Transaction [Line Items]
Costs for services	611	549	504
Southern Company Services, Inc. \| Georgia Power
Related Party Transaction [Line Items]
Costs for services	857	762	663
Southern Company Services, Inc. \| Southern Power
Related Party Transaction [Line Items]
Costs for services	86	86	89
Southern Company Services, Inc. \| Southern Company Gas
Related Party Transaction [Line Items]
Costs for services	261	262	239
PowerSecure \| Southern Company Gas \| US General Services Administration
Related Party Transaction [Line Items]
Costs for services	29	10
Contract amount		77
Non-Fuel Expense \| Mississippi Power \| Alabama Power
Related Party Transaction [Line Items]
Costs for services	5	6	10
Purchased Power from Affiliates \| Southern Power
Related Party Transaction [Line Items]
Costs for services	145	154	139
Operating Lease PPA \| Southern Power
Related Party Transaction [Line Items]
Costs for services	116	116	112
Electric Transmission \| Southern Company Services, Inc. \| Southern Power
Related Party Transaction [Line Items]
Costs for services	$ 33	$ 39	$ 28

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Southern Company Gas
Disaggregation of Revenue [Line Items]
Period for collection of revenue prior to billings	24 months
Total operating revenues	$ 4,702	5,962	4,380
Southern Company Gas \| Alternative revenue programs
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 20	$ (5)	$ 11

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Revenue (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023
Mississippi Power
Concentration Risk [Line Items]
Wholesale customers representing total operating revenues	14%

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Income and Other Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Southern Power
Tax Credit Carryforward [Line Items]
Percentage reduction in tax basis of assets	50%
Southern Company Gas
Tax Credit Carryforward [Line Items]
Excise taxes collected	$ 133	$ 162	$ 122
Included In Operating Expenses \| Southern Company Gas
Tax Credit Carryforward [Line Items]
Excise taxes collected	$ 129	$ 158	$ 119

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Total AFUDC and Interest Capitalized (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	$ 400	$ 327	$ 282
Alabama Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	109	90	68
Georgia Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	251	213	190
Southern Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	3	0	6
Southern Company Gas
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	$ 37	$ 24	$ 18

SUMMARY OF SIGNIFICANT ACCOU_11

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Average AFUDC Composite Rates (Details)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Alabama Power
Capitalized Contract Cost [Line Items]
Composite rate	8.10%	7.90%	7.90%
Georgia Power
Capitalized Contract Cost [Line Items]
Composite rate	7.60%	7.30%	7.20%
Mississippi Power
Capitalized Contract Cost [Line Items]
Composite rate	0%	5.30%	2.50%
Atlanta Gas Light
Capitalized Contract Cost [Line Items]
Composite rate	7.40%	7.60%	7.70%
Chattanooga Gas
Capitalized Contract Cost [Line Items]
Composite rate	7.10%	7.10%	7.10%
Nicor Gas
Capitalized Contract Cost [Line Items]
Composite rate	4.60%	2%	0.10%

SUMMARY OF SIGNIFICANT ACCOU_12

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Other Intangible Assets and Liabilities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment	$ 119
Goodwill	5,161	$ 5,161	$ 5,280
Southern Company Gas
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 5,015	$ 5,015

SUMMARY OF SIGNIFICANT ACCOU_13

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Goodwill Balances (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 5,161	$ 5,161	$ 5,280
Southern Company Gas
Goodwill [Line Items]
Goodwill	5,015	5,015
Gas distribution operations \| Southern Company Gas
Goodwill [Line Items]
Goodwill	4,034	4,034
Gas marketing services \| Southern Company Gas
Goodwill [Line Items]
Goodwill	$ 981	$ 981

SUMMARY OF SIGNIFICANT ACCOU_14

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 669	$ 671
Accumulated Amortization	(376)	(340)
Other Intangible Assets, Net	293	331
Intangible assets, gross	744	746
Intangible assets, net	368	406
FCC licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	75	75
Accumulated Amortization	0	0
Other Intangible Assets, Net	75	75
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	212	212
Accumulated Amortization	(172)	(162)
Other Intangible Assets, Net	40	50
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	64	64
Accumulated Amortization	(53)	(44)
Other Intangible Assets, Net	11	20
PPA fair value adjustments
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	390	390
Accumulated Amortization	(148)	(129)
Other Intangible Assets, Net	242	261
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3	5
Accumulated Amortization	(3)	(5)
Other Intangible Assets, Net	0	0
Southern Power
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	(148)	(129)
Southern Power \| PPA fair value adjustments
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	390	390
Accumulated Amortization	(148)	(129)
Other Intangible Assets, Net	242	261
Southern Company Gas
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	182	182
Accumulated Amortization	(166)	(156)
Other Intangible Assets, Net	16	26
Intangible assets, net	16	26
Southern Company Gas \| Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	156	156
Accumulated Amortization	(145)	(139)
Other Intangible Assets, Net	11	17
Southern Company Gas \| Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	26	26
Accumulated Amortization	(21)	(17)
Other Intangible Assets, Net	$ 5	$ 9

SUMMARY OF SIGNIFICANT ACCOU_15

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Amortization of Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	$ 38	$ 39	$ 44
Estimated future amortization
2024	35
2025	32
2026	27
2027	24
2028	24
Southern Power
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	20	20	20
Estimated future amortization
2024	20
2025	20
2026	20
2027	20
2028	20
Southern Company Gas
Estimated future amortization
2024	7
2025	6
2026	3
2027	0
2028	0
Southern Company Gas \| Gas marketing services
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	10	$ 11	$ 15
Operating Revenues
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	$ 20

SUMMARY OF SIGNIFICANT ACCOU_16

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Transmission Receivables/Prepayments (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023
Southern Power
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Period of reimbursement for transmission costs	5 years

SUMMARY OF SIGNIFICANT ACCOU_17

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 748	$ 1,917
Restricted cash:
Total cash, cash equivalents, and restricted cash	921	2,037	$ 1,829	$ 1,068
Other current assets
Restricted cash:
Restricted cash	141	62
Other deferred charges and assets
Restricted cash:
Restricted cash	31	58
Alabama Power
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	324	687
Restricted cash:
Total cash, cash equivalents, and restricted cash	409	687	1,060	530
Alabama Power \| Other current assets
Restricted cash:
Restricted cash	85	0
Alabama Power \| Other deferred charges and assets
Restricted cash:
Restricted cash	0	0
Georgia Power
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	9	364
Restricted cash:
Total cash, cash equivalents, and restricted cash	75	480	33	9
Georgia Power \| Other current assets
Restricted cash:
Restricted cash	37	60
Georgia Power \| Other deferred charges and assets
Restricted cash:
Restricted cash	29	56
Southern Power
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	124	131
Restricted cash:
Total cash, cash equivalents, and restricted cash	144	133	135	182
Southern Power \| Other current assets
Restricted cash:
Restricted cash	17	0
Southern Power \| Other deferred charges and assets
Restricted cash:
Restricted cash	3	3
Southern Power \| Estimated Construction Completion Costs \| Deuel Harvest
Restricted cash:
Restricted cash	3	3
Southern Power \| Proceeds From Issuance Of Solid Waste Disposal Facility Revenue Bonds
Restricted cash:
Restricted cash	17
Southern Company Gas
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	33	81
Restricted cash:
Total cash, cash equivalents, and restricted cash	35	83	$ 48	$ 19
Southern Company Gas \| Other current assets
Restricted cash:
Restricted cash	2	2
Southern Company Gas \| Other deferred charges and assets
Restricted cash:
Restricted cash	$ 0	$ 0

SUMMARY OF SIGNIFICANT ACCOU_18

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Storm Damage and Reliability Reserves (Details) - USD ($) $ in Millions		12 Months Ended			24 Months Ended
	Jan. 01, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Apr. 04, 2023	Apr. 03, 2023
Liability for Catastrophe Claims [Line Items]
Reliability reserve, amount deferred		$ 63	$ 191		$ 191
Alabama Power
Liability for Catastrophe Claims [Line Items]
Additional accruals authorized by state PSCs				$ 65
Reliability reserve, amount deferred		52	166		166
Alabama Power \| Weather-related damages
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves		24
Georgia Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves	$ 31				213
Georgia Power \| Weather-related damages
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves		82
Mississippi Power
Liability for Catastrophe Claims [Line Items]
Reliability reserve, amount deferred		11	25		$ 25	$ 11.7	$ 8.3
Mississippi Power \| Weather-related damages
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves		0
Major storms
Liability for Catastrophe Claims [Line Items]
Storm damage reserves			239	286
Major storms \| Alabama Power
Liability for Catastrophe Claims [Line Items]
Additional accruals authorized by state PSCs				65
Storm damage reserves			19	75
Major storms \| Georgia Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves			213	213
Major storms \| Mississippi Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves		$ 11.7	$ 6.9	$ (1.8)

SUMMARY OF SIGNIFICANT ACCOU_19

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES- Storm Damage Reserves (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at December 31, 2022	$ 216
Balance at December 31, 2023	66
Accrual
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Accrual	61
Weather-related damages
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Weather-related damages	(211)
Alabama Power
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at December 31, 2022	97
Balance at December 31, 2023	76
Alabama Power \| Accrual
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Accrual	18
Alabama Power \| Weather-related damages
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Weather-related damages	(39)
Georgia Power
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at December 31, 2022	83
Balance at December 31, 2023	(54)	$ (83)
Georgia Power \| Accrual
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Accrual	31
Georgia Power \| Weather-related damages
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Weather-related damages	(168)
Mississippi Power
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Balance at December 31, 2022	36
Balance at December 31, 2023	44
Mississippi Power \| Accrual
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Accrual	12
Mississippi Power \| Weather-related damages
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Weather-related damages	$ (4)

SUMMARY OF SIGNIFICANT ACCOU_20

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Natural Gas for Sale (Narrative) (Details) - Nicor Gas $ in Millions	Dec. 31, 2023 USD ($)
Inventory [Line Items]
LIFO inventory balance	$ 186
Estimated replacement cost of inventory	$ 268

SUMMARY OF SIGNIFICANT ACCOU_21

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts (Narrative) (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Uncollectible accounts, average percent of revenues (less than)	1%	1%	1%

SUMMARY OF SIGNIFICANT ACCOU_22

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Narrative) (Details) - Atlanta Gas Light	Dec. 31, 2023 customer
Concentration Risk [Line Items]
Number of customers in Georgia	13
Percent of highest month's estimated bill	200%

SUMMARY OF SIGNIFICANT ACCOU_23

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Financial Instruments (Narrative) (Details)	Dec. 31, 2023 USD ($)
Alabama Power
Derivative [Line Items]
Derivative collateral obligation to return cash	$ 0

SUMMARY OF SIGNIFICANT ACCOU_24

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of AOCI (Loss) Balances, Net of Tax Effects (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 34,532	$ 32,276	$ 32,234
Total other comprehensive income	(10)	71	158
Ending balance	35,225	34,532	32,276
Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(149)
Total other comprehensive income	28
Ending balance	(121)	(149)
Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18)
Total other comprehensive income	(38)
Ending balance	(56)	(18)
Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(167)	(237)	(395)
Total other comprehensive income	(10)
Ending balance	(177)	(167)	(237)
Southern Power
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	6,916	6,598	6,631
Total other comprehensive income	1	10	40
Ending balance	6,698	6,916	6,598
Southern Power \| Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9)
Total other comprehensive income	8
Ending balance	(1)	(9)
Southern Power \| Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9)
Total other comprehensive income	(7)
Ending balance	(16)	(9)
Southern Power \| Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(18)	(27)	(67)
Total other comprehensive income	1
Ending balance	(17)	(18)	(27)
Southern Company Gas
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Total other comprehensive income	(15)	7	$ 46
Southern Company Gas \| Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(25)
Total other comprehensive income	1
Ending balance	(24)	(25)
Southern Company Gas \| Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	56
Total other comprehensive income	(16)
Ending balance	40	56
Southern Company Gas \| Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	31
Total other comprehensive income	(15)
Ending balance	$ 16	$ 31

REGULATORY MATTERS - Schedule o

REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions		12 Months Ended			24 Months Ended
	Jan. 01, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2020
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 6,523	$ 5,833		$ 5,833
Regulatory asset amortization period		4 years
Regulatory asset		$ 66	216		216
Plant In Service Net Of Depreciation		(90,703)	(82,232)		(82,232)
Other Regulatory Assets Current		1,120	860		860
Revision of Prior Period, Reclassification, Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Plant In Service Net Of Depreciation			42		42	$ 600
Other Regulatory Assets Current			42		42
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		2,720	2,340		2,340
Customer refund		304
Regulatory asset		76	97		97
Plant In Service Net Of Depreciation		(24,298)	(23,002)		(23,002)
Other Regulatory Assets Current		385	372		372
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		5,090	4,663		4,663
Regulatory asset			83		83
Regulatory liabilities		54	83		83
Costs recovered annually		5	12	$ 12
Storm damage reserves	$ 31				213
Plant In Service Net Of Depreciation		(35,415)	(28,764)		(28,764)
Other Regulatory Assets Current		423	324		324
Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		90	4		4
Regulatory asset		44	36		36
Plant In Service Net Of Depreciation		(3,731)	(3,565)		(3,565)
Other Regulatory Assets Current		56	72		72
Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(2,225)	(1,891)		(1,891)
Plant In Service Net Of Depreciation		(15,306)	(14,447)		(14,447)
Other Regulatory Assets Current		141	119		119
Deferred Income Tax Credits
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(4,686)	(5,251)		(5,251)
Deferred Income Tax Credits \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(1,506)	(1,925)		(1,925)
Deferred Income Tax Credits \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(2,161)	(2,244)		(2,244)
Deferred Income Tax Credits \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(241)	(269)		(269)
Regulatory liabilities		11
Deferred Income Tax Credits \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(759)	(788)		(788)
Other Cost of Removal Obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(1,312)	(64)		(64)
Other Cost of Removal Obligations \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		28	0		0
Other Cost of Removal Obligations \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		617	(38)		(38)
Other Cost of Removal Obligations \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(186)	0		0
Other Cost of Removal Obligations \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(1,771)	(26)		(26)
Over Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(287)	(1,430)		(1,430)
Over Recovered Regulatory Clause Revenues \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(3)	11		11
Over Recovered Regulatory Clause Revenues \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(46)	462		462
Over Recovered Regulatory Clause Revenues \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	(196)		(196)
Over Recovered Regulatory Clause Revenues \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (238)	(1,707)		(1,707)
Regulatory liability amortization period		5 years
Reliability reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (179)	(191)		(191)
Reliability reserves \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(143)	(166)		(166)
Reliability reserves \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Reliability reserves \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(36)	(25)		(25)
Reliability reserves \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Storm/Property Damage Reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(120)	(216)		(216)
Storm/Property Damage Reserves \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(76)	(97)		(97)
Storm/Property Damage Reserves \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	(83)		(83)
Storm/Property Damage Reserves \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(44)	(36)		(36)
Storm/Property Damage Reserves \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Customer Refunds
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(19)	(183)		(183)
Customer Refunds \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(15)	(62)		(62)
Regulatory liabilities		15	62		62
Customer Refunds \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(4)	(121)		(121)
Regulatory liabilities			119		119
Customer Refunds \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Customer Refunds \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Fuel Hedging (Realized And Unrealized) gains
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(6)
Fuel Hedging (Realized And Unrealized) gains \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(5)
Fuel Hedging (Realized And Unrealized) gains \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(1)
Fuel Hedging (Realized And Unrealized) gains \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets
Fuel Hedging (Realized And Unrealized) gains \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0
Other Regulatory Liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		(308)	(239)		(239)
Other Regulatory Liabilities \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (74)	(40)		(40)
Regulatory liability amortization period		11 years
Other Regulatory Liabilities \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (18)	(21)		(21)
Regulatory liability amortization period		9 years
Other Regulatory Liabilities \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (2)	(3)		(3)
Regulatory liability amortization period		4 years
Other Regulatory Liabilities \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ (101)	(93)		(93)
Regulatory liability amortization period		20 years
Excess Deferred Income Tax Liabilities Not Subject to Normalization \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 1
Fuel Hedging (Realized And Unrealized) losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets			(83)		(83)
Fuel Hedging (Realized And Unrealized) losses \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets			(38)		(38)
Regulatory liability amortization period		3 years 6 months
Fuel Hedging (Realized And Unrealized) losses \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets			(21)		(21)
Regulatory liability amortization period		3 years
Fuel Hedging (Realized And Unrealized) losses \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets			(24)		(24)
Regulatory liability amortization period		4 years
Fuel Hedging (Realized And Unrealized) losses \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets			0		0
AROs
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 5,733	6,096		6,096
AROs \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 1,936	1,971		1,971
AROs \| Alabama Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		64 years
AROs \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 3,505	3,829		3,829
AROs \| Georgia Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		56 years
AROs \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 247	242		242
AROs \| Mississippi Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		55 years
AROs \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 0	0		0
AROs \| Southern Company Gas \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		85 years
Retiree Benefit Plans
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 3,011	2,517		2,517
Retiree Benefit Plans \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 815	675		675
Retiree Benefit Plans \| Alabama Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		13 years
Retiree Benefit Plans \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 976	848		848
Retiree Benefit Plans \| Georgia Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		14 years
Retiree Benefit Plans \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 140	113		113
Retiree Benefit Plans \| Mississippi Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		13 years
Retiree Benefit Plans \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 146	114		114
Retiree Benefit Plans \| Southern Company Gas \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		14 years
Remaining Net Book Value of Retired Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 1,357	1,543		1,543
Remaining Net Book Value of Retired Assets \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		499	562		562
Remaining Net Book Value of Retired Assets \| Alabama Power \| Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		451
Remaining Net Book Value of Retired Assets \| Alabama Power \| Plant Barry Unit 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 39
Remaining Net Book Value of Retired Assets \| Alabama Power \| Maximum \| Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		14 years
Remaining Net Book Value of Retired Assets \| Alabama Power \| Maximum \| Plant Barry Unit 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		11 years
Remaining Net Book Value of Retired Assets \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 841	$ 962		$ 962
Remaining Net Book Value of Retired Assets \| Georgia Power \| Plant Wansley Units 1 and 2
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		488
Remaining Net Book Value of Retired Assets \| Georgia Power \| Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		339
Remaining Net Book Value of Retired Assets \| Georgia Power \| Plant Branch Unit 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 8
Remaining Net Book Value of Retired Assets \| Georgia Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period			3 years		3 years		4 years
Remaining Net Book Value of Retired Assets \| Georgia Power \| Maximum \| Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		12 years
Remaining Net Book Value of Retired Assets \| Georgia Power \| Minimum \| Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		1 year
Remaining Net Book Value of Retired Assets \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 17	$ 19		$ 19
Remaining Net Book Value of Retired Assets \| Mississippi Power \| Plant Watson and Plant Greene County \| Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		10 years
Remaining Net Book Value of Retired Assets \| Mississippi Power \| Plant Watson and Plant Greene County \| Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		14 years
Remaining Net Book Value of Retired Assets \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 0	0		0
Deferred Income Tax Charges
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		897	866		866
Deferred Income Tax Charges \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		262	250		250
Deferred Income Tax Charges \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		605	583		583
Deferred Income Tax Charges \| Georgia Power \| Plant Vogtle Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 17
Regulatory asset amortization period		10 years
Regulatory asset		$ 145
Deferred Income Tax Charges \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		28	30		30
Deferred Income Tax Charges \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Under Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		413	953		953
Under Recovered Regulatory Clause Revenues \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 381	788		788
Under Recovered Regulatory Clause Revenues \| Alabama Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		7 years
Under Recovered Regulatory Clause Revenues \| Alabama Power \| Minimum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		1 year
Under Recovered Regulatory Clause Revenues \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 0	0		0
Regulatory asset amortization period		2 years
Under Recovered Regulatory Clause Revenues \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 12	31		31
Under Recovered Regulatory Clause Revenues \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 20	134		134
Regulatory asset amortization period		5 years
Fuel Hedging (Realized And Unrealized) losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 270	60		60
Fuel Hedging (Realized And Unrealized) losses \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		100	15		15
Regulatory asset amortization period	5 years
Fuel Hedging (Realized And Unrealized) losses \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		121	45		45
Fuel Hedging (Realized And Unrealized) losses \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		49	0		0
Fuel Hedging (Realized And Unrealized) losses \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Regulatory asset amortization period	2 years
Deferred Depreciation
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		270
Deferred Depreciation \| Plant Scherer Units 1 through 3
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 70
Regulatory asset amortization period		6 years
Deferred Depreciation \| Plant Bowen Units 1 and 2
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 40
Deferred Depreciation \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		143
Deferred Depreciation \| Alabama Power \| Plant Barry Unit 5
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		57
Deferred Depreciation \| Alabama Power \| Plant Barry
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		24
Deferred Depreciation \| Alabama Power \| Plant Gaston Unit 5
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		62
Deferred Depreciation \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		127
Deferred Depreciation \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0
Deferred Depreciation \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0
Environmental Remediation
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		255	294		294
Environmental Remediation \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Environmental Remediation \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		20	25		25
Environmental Remediation \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Environmental Remediation \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		235	269		269
Loss on Reacquired Debt
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		238	257		257
Loss on Reacquired Debt \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 35	38		38
Loss on Reacquired Debt \| Alabama Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		24 years
Loss on Reacquired Debt \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 197	213		213
Loss on Reacquired Debt \| Georgia Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		29 years
Loss on Reacquired Debt \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 5	5		5
Loss on Reacquired Debt \| Mississippi Power \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		18 years
Loss on Reacquired Debt \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 1	1		1
Loss on Reacquired Debt \| Southern Company Gas \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		4 years
Vacation Pay
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 217	212		212
Regulatory asset amortization period		1 year
Vacation Pay \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 83	82		82
Vacation Pay \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		107	108		108
Vacation Pay \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		11	10		10
Vacation Pay \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		16	12		12
Software and Cloud Computing Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 150	111		111
Regulatory asset amortization period		5 years
Software and Cloud Computing Costs \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 59	46		46
Regulatory asset amortization period		10 years
Software and Cloud Computing Costs \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 84	59		59
Software and Cloud Computing Costs \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		2	0		0
Software and Cloud Computing Costs \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 5	6		6
Regulatory asset amortization period		10 years
Regulatory Clauses
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 140	142		142
Regulatory Clauses \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		112	142		142
Regulatory Clauses \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Regulatory Clauses \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Regulatory Clauses \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		28	0		0
Storm Damage
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		92	44		44
Storm Damage \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Storm Damage \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		54	0		0
Storm Damage \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 38	44		44
Regulatory asset amortization period		7 years
Storm Damage \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 0	0		0
Nuclear Outage
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		83	82		82
Nuclear Outage \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 50	52		52
Nuclear Outage \| Alabama Power \| Plant Farley
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		18 months
Nuclear Outage \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 33	30		30
Nuclear Outage \| Georgia Power \| Maximum \| Plant Hatch (nuclear) Units 1 and 2
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		24 months
Nuclear Outage \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 0	0		0
Nuclear Outage \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Long Term Debt Fair Value Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		60	69		69
Long Term Debt Fair Value Adjustment \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Long Term Debt Fair Value Adjustment \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Long Term Debt Fair Value Adjustment \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Long Term Debt Fair Value Adjustment \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 60	69		69
Long Term Debt Fair Value Adjustment \| Southern Company Gas \| Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		15 years
Qualifying Repairs Of Natural Gas Distribution Systems
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 40	26		26
Qualifying Repairs Of Natural Gas Distribution Systems \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Qualifying Repairs Of Natural Gas Distribution Systems \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Qualifying Repairs Of Natural Gas Distribution Systems \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Qualifying Repairs Of Natural Gas Distribution Systems \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 40	26		26
Qualifying Repairs Of Natural Gas Distribution Systems \| Atlanta Gas Light
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		20 years
Plant Daniel Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 25	27		27
Plant Daniel Units 3 and 4 \| Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		17
Plant Daniel Units 3 and 4 \| Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		8
Plant Daniel Units 3 and 4 \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Plant Daniel Units 3 and 4 \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Plant Daniel Units 3 and 4 \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		25	27		27
Plant Daniel Units 3 and 4 \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Kemper County energy facility assets, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		7	20		20
Kemper County energy facility assets, net \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Kemper County energy facility assets, net \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Kemper County energy facility assets, net \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		7	20		20
Regulatory asset		9
Regulatory liabilities		2
Kemper County energy facility assets, net \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		0	0		0
Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		182	171		171
Other Regulatory Assets \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 39	36		36
Regulatory asset amortization period		20 years
Other Regulatory Assets \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 33	27		27
Regulatory asset amortization period		10 years
Other Regulatory Assets \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 18	16		16
Regulatory asset amortization period		14 years
Other Regulatory Assets \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 93	$ 92		$ 92
Regulatory asset amortization period		15 years
CCR AROs \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		38 years
CCR AROs \| Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period	4 years	3 years
Regulatory Clauses, Amortized Through PEP \| Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net regulatory assets		$ 12

REGULATORY MATTERS - APC Certif

REGULATORY MATTERS - APC Certificate of Convenience and Necessity and RGC (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 MW	Dec. 31, 2023 USD ($)	Jun. 14, 2023 MW	Jun. 13, 2023 MW	Apr. 04, 2023 claim MW	Dec. 31, 2022 USD ($)
Schedule of Regulatory Assets and Liabilities [Line Items]
Plant in service, net of depreciation \| $		$ 90,703				$ 82,232
Approved solar PPAs \| claim					2
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Plant in service, net of depreciation \| $		$ 24,298				$ 23,002
Renewable generation certificate, authorized generating capacity (in MWs)					500
Additional generating capacity (in MWs)					160
Renewable generation certificate, generating capacity (in MWs)					490
Additional renewable capacity (in MWs)			2,400
Size of allowable projects (in MWs)			200	80
Approval limit (in MWs)			400	160
Plant Barry Unit 8 \| Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Approximate nameplate capacity (in MWs)	720

REGULATORY MATTERS - APC Rate R

REGULATORY MATTERS - APC Rate RSE (Details) - Alabama Power - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2024	Oct. 03, 2023	Feb. 28, 2022
Public Utilities, General Disclosures [Line Items]
Rate adjustment period		2 years
Maximum percentage of rate RSE		4%
Maximum annual percentage of ratio rate		5%
Adjusting point of weighted cost of equity		5.98%
Percent of basis points		0.07%
Authorized ROE		52.30%	52.20%
Customer refundable fees, refund payments, tranche one, percentage		25%
Customer refundable fees, refund payments, tranche two, percentage		40%
Customer refundable fees, refund payments, tranche two, percentage		75%
Customer refundable fees, refund payments, tranche one, review year with rate RSE upward adjustment, percentage		50%
Contract with customer, liability, bill credits							$ 55
Rate RSE refund liability		$ 15	$ 62	$ 181
Rate RSE refund liability, portion attributable to reduce under recovered balance							$ 126
Customer refund		304
Deferred income taxes		$ 81				$ 24
Minimum
Public Utilities, General Disclosures [Line Items]
Public utilities, actual weighted common equity return, threshold, percentage		6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one		6.15%	6.15%	6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two		6.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three		7.15%
Public utilities, actual weighted common equity return, threshold, review year with rate RSE upward adjustment, percentage		6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one		6.15%
Maximum
Public Utilities, General Disclosures [Line Items]
Public utilities, actual weighted common equity return, threshold, percentage		7.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one		6.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two		7.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three		7.65%
Customer refundable fees, refund payments, percentage		7.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one		6.90%
Customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage		6.90%
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Authorized ROE	55%
Deferred income taxes	$ 14				$ 67

REGULATORY MATTERS - APC Rate C

REGULATORY MATTERS - APC Rate CNP New Plant (Details) - Alabama Power - USD ($) $ in Millions	Mar. 24, 2023	Dec. 01, 2023	Oct. 03, 2022
Public Utilities, General Disclosures [Line Items]
Increase to annual revenue requirement		$ 91	$ 34
Increase to annual revenue requirement, percentage		1.40%	0.60%
Requested rate increase (decrease), amount	$ 78
Requested rate increase (decrease), percentage	1.10%

REGULATORY MATTERS - APC Rate_2

REGULATORY MATTERS - APC Rate CNP (Details) - Alabama Power - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements	$ 120	$ 103	$ 120
Retail revenue requirement for environmental compliance		$ 23	$ 255	$ 59
Retail revenue requirement for environmental compliance, as a percentage		(0.30%)	3.70%
Over (under) recovered environmental clause	(47)	$ (33)	$ (47)
Public utilities, approved rate increase (decrease), amount	$ 318
Approved rate increase, percent	4.60%
Other regulatory assets, current
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements	$ 18	18	18
Over (under) recovered environmental clause		(8)
Other regulatory assets, deferred
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements	$ 102	85	$ 102
Over (under) recovered environmental clause		$ (25)

REGULATORY MATTERS - APC Rate E

REGULATORY MATTERS - APC Rate ECR (Details) - Alabama Power $ in Millions		1 Months Ended					12 Months Ended
	Nov. 09, 2023 USD ($) $ / KWH_Kilowatt_hour	Jan. 31, 2025 $ / KWH_Kilowatt_hour	Dec. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Nov. 30, 2022 $ / KWH_Kilowatt_hour	Aug. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Jul. 31, 2022 $ / KWH_Kilowatt_hour	Dec. 31, 2023 USD ($) $ / KWH_Kilowatt_hour	Feb. 28, 2022 USD ($)
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) \| $ / KWH_Kilowatt_hour	3.270		3.510	2.557	2.557	1.960	0.05910
Current billing rates under rate ECR, amount	$ 126		$ 500		$ 310
Rate RSE refund liability, portion attributable to reduce under recovered balance								$ 126
Over (under) recovered fuel cost			(622)				$ (246)
Regulatiry Assets, Under Recovered Fuel Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost			(102)				$ (246)
Other regulatory assets, deferred
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost			$ (520)
Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) \| $ / KWH_Kilowatt_hour		0.05910

REGULATORY MATTERS - APC Accoun

REGULATORY MATTERS - APC Accounting Orders and Plant Greene County (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 19,069	$ 20,148
Alabama Power
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 5,090	5,372
Percent ownership	14%
Alabama Power \| Software Accounting Order
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 59	46
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 887	$ 828
Mississippi Power \| Plant Greene County Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Percent ownership			40%

REGULATORY MATTERS - APC Rate N

REGULATORY MATTERS - APC Rate NDR and Reliability Reserve Accounting Order (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2022	Jul. 12, 2022
Public Utilities, General Disclosures [Line Items]
Reliability reserve, amount deferred	$ 63,000,000	$ 63,000,000	$ 191,000,000
Net regulatory assets	6,523,000,000	6,523,000,000	5,833,000,000
Plant in service, net of depreciation	90,703,000,000	90,703,000,000	82,232,000,000
Other utility plant, net	499,000,000	499,000,000	599,000,000
Other regulatory assets	1,120,000,000	1,120,000,000	860,000,000
Reliability reserves
Public Utilities, General Disclosures [Line Items]
Net regulatory assets	(179,000,000)	(179,000,000)	(191,000,000)
Revision of Prior Period, Reclassification, Adjustment
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation			(42,000,000)		$ (600,000,000)
Other utility plant, net					$ 600,000,000
Other regulatory assets			42,000,000
Alabama Power
Public Utilities, General Disclosures [Line Items]
Minimum natural disaster reserve balance, triggering establishment charge	50,000,000	50,000,000
Natural disaster reserve authorized limit	75,000,000	75,000,000				$ 35,000,000
Reliability reserve, amount deferred	52,000,000	52,000,000	166,000,000
Net regulatory assets	2,720,000,000	2,720,000,000	2,340,000,000
Maximum rate NDR charge per month, monthly nonresidential customer account	5	5				10
Maximum rate NDR charge per month, monthly residential customer account	2.50	2.50				$ 5
Additional accruals authorized by state PSCs				$ 65,000,000
Annual recovery amount		12,000,000	14,000,000	$ 6,000,000
Regulatory asset, amortization period	76,000,000	76,000,000	97,000,000
NDR, expected recovery amount		12,000,000
Plant in service, net of depreciation	24,298,000,000	24,298,000,000	23,002,000,000
Other utility plant, net	499,000,000	499,000,000	599,000,000
Other regulatory assets	385,000,000	385,000,000	372,000,000
Alabama Power \| Reliability reserves
Public Utilities, General Disclosures [Line Items]
Net regulatory assets	(143,000,000)	$ (143,000,000)	$ (166,000,000)
Accrual	$ 75,000,000
Alabama Power \| Minimum
Public Utilities, General Disclosures [Line Items]
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits		24 months
Alabama Power \| Maximum
Public Utilities, General Disclosures [Line Items]
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits		48 months

REGULATORY MATTERS - GPC Tariff

REGULATORY MATTERS - GPC Tariffs (Details) - Georgia Power $ in Millions	Dec. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	$ 216
Requested rate increase (decrease), amount, due in 2024	191
Requested rate increase (decrease), amount, due in 2025	157
Traditional base
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	194
Requested rate increase (decrease), amount, due in 2024	275
Requested rate increase (decrease), amount, due in 2025	192
ECCR
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	(21)
Requested rate increase (decrease), amount, due in 2024	(99)
Requested rate increase (decrease), amount, due in 2025	(12)
DSM
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	37
Requested rate increase (decrease), amount, due in 2024	10
Requested rate increase (decrease), amount, due in 2025	(25)
MFF
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	6
Requested rate increase (decrease), amount, due in 2024	5
Requested rate increase (decrease), amount, due in 2025	$ 2

REGULATORY MATTERS - GPC Rate P

REGULATORY MATTERS - GPC Rate Plans, Integrated Resource Plan and COVID-19 Costs (Details) $ in Millions									1 Months Ended				3 Months Ended			12 Months Ended									60 Months Ended	68 Months Ended
	Mar. 24, 2024 USD ($)	Jan. 12, 2024 turbine MW	Jan. 01, 2024 MW	Oct. 27, 2023 MW	Aug. 30, 2023 USD ($)	Aug. 01, 2023 USD ($)	May 16, 2023 USD ($)	Jan. 01, 2022 USD ($)	Dec. 31, 2022 USD ($)	Aug. 31, 2022 USD ($)	Jul. 31, 2022 agreement	Nov. 30, 2021 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2028 MW	Dec. 31, 2025 USD ($) MW	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2009 USD ($)	Dec. 31, 2028 MW	Dec. 31, 2028 MW	Oct. 06, 2023 pump	Mar. 31, 2023 USD ($)	Jan. 31, 2018 USD ($)	Dec. 31, 2016
Public Utilities, General Disclosures [Line Items]
Regulatory asset amortization period													4 years						4 years
Net regulatory assets									$ 5,833				$ 6,523		$ 5,833				$ 6,523	$ 5,833
Customer Refunds
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									(183)				(19)		(183)				(19)	(183)
Georgia Power
Public Utilities, General Disclosures [Line Items]
Approved rate decrease								$ 10
Public utilities, approved rate increase (decrease), amount												$ 252
Requested rate increase (decrease), amount							$ 1,100
Net regulatory assets									4,663				$ 5,090		4,663				5,090	4,663
Requested number of power purchase agreements to be certified \| agreement											6
Requested number of affiliate power purchase agreements to be certified \| agreement											5
Requested rate increase (decrease), percentage							54%
Pre-tax charge to income														$ 160	407				$ 567
After tax charge to income														$ 120	304
Georgia Power \| Plant Scherer (coal) Unit 3
Public Utilities, General Disclosures [Line Items]
Percent Ownership													75%						75%
Approved additional generating capacity (in MW) \| MW				614
Georgia Power \| Plant Gaston Units 1 through 4
Public Utilities, General Disclosures [Line Items]
Percent Ownership													50%						50%
Approved additional generating capacity (in MW) \| MW				500
Georgia Power \| ECCR
Public Utilities, General Disclosures [Line Items]
Regulatory asset amortization period													4 years						4 years
Approved rate decrease																			$ 20
Compliance costs expected to be incurred																			$ 300
Georgia Power \| 2022 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity													10.50%						10.50%
Equity rate of return on common equity													56%						56%
Portion of actual earnings above approved ROE band applied to reduce regulatory assets																			40%
Portion of actual earnings above approved ROE band refunded to customers																			40%
Portion of actual earnings above approved ROE band retained by subsidiary company																			20%
Georgia Power \| 2019 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity																							10.50%
Portion of actual earnings above approved ROE band applied to reduce regulatory assets																							40%
Portion of actual earnings above approved ROE band refunded to customers																						40%
Portion of actual earnings above approved ROE band retained by subsidiary company																						20%
Customer refund liability in absence of base rate case									5						5					5								$ 117
Georgia Power \| Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Requested additional generating capacity (in MW) \| MW																									750	230
Georgia Power \| Scenario, Forecast \| ECCR
Public Utilities, General Disclosures [Line Items]
Approved rate decrease																		$ 60
Compliance costs expected to be incurred																	$ 330	305
Georgia Power \| Scenario, Forecast \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Requested additional generating capacity (in MW) \| MW			1,567													228	380
Georgia Power \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount																					$ 2,100
Requested rate increase (decrease), amount																					3,600
Requested rate increase, annual amount						$ 318
Georgia Power \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity																														10.95%
Public utilities, approved rate increase (decrease), amount					$ 5,462																2,100
Requested rate increase (decrease), amount					729
Decrease in tariff									(36)
Requested recovery of construction costs					7,562
Requested recovery of rate base items					1,020
Project capital cost forecast																													$ 7,300
Estimated in-service capital cost																								$ 4,418
Approved recovery of retail base rate																					362
Requested recovery of remaining retail rate base items					$ 656
Return on equity reduction, negative impact on earnings																			$ 310	300	$ 270
Requested rate increase (decrease), percentage					5%
Pre-tax charge to income													$ 228
After tax charge to income													$ 170
Percent Ownership													45.70%						45.70%
Georgia Power \| Plant Vogtle Units 3 and 4 \| Seventeenth Vogtle Construction Monitoring Report
Public Utilities, General Disclosures [Line Items]
Requested recovery of construction costs					$ 8,826
Requested recovery of rate base items					$ 1,070
Georgia Power \| Plant Vogtle Units 3 and 4 \| Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Return on equity reduction, negative impact on earnings	$ 30																	$ 90
Georgia Power \| Plant Yates \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Number of turbines \| turbine		3
Approved additional generating capacity (in MW) \| MW		442
Georgia Power \| Plant Vogtle Unit 4
Public Utilities, General Disclosures [Line Items]
Number of RCP's \| pump																											1
Georgia Power \| Plant Bowen Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Approved additional generating capacity (in MW) \| MW				1,400
Georgia Power \| Plant Tugalo
Public Utilities, General Disclosures [Line Items]
Planned expenses to modernize plant										$ 115
Georgia Power \| Customer Refunds
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									(121)				$ (4)		(121)				$ (4)	(121)
Georgia Power \| Customer Refunds \| 2019 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Portion of actual earnings above approved ROE band refunded to customers, value									5						5					5								$ 117
Remaining Net Book Value of Retired Assets
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									1,543				1,357		1,543				1,357	1,543
Remaining Net Book Value of Retired Assets \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Net regulatory assets									$ 962				841		$ 962				841	$ 962
Remaining Net Book Value of Retired Assets \| Georgia Power \| Plant Wansley Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Net regulatory assets													$ 488						$ 488
Maximum \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount							$ 200
Requested additional generating capacity (in MW) \| MW				1,000
Maximum \| Georgia Power \| 2022 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity													11.90%						11.90%
Maximum \| Georgia Power \| 2019 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity									12%						12%					12%	12%		12%
Maximum \| Georgia Power \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Number of RCP's \| pump																											7
Maximum \| Georgia Power \| Plant Yates
Public Utilities, General Disclosures [Line Items]
Requested additional generating capacity (in MW) \| MW				1,400
Maximum \| Georgia Power \| Plant Vogtle Unit 4
Public Utilities, General Disclosures [Line Items]
Number of RCP's \| pump																											4
Maximum \| Remaining Net Book Value of Retired Assets \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Regulatory asset amortization period									3 years						3 years					3 years		4 years
Minimum \| Georgia Power \| 2022 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity													9.50%						9.50%
Minimum \| Georgia Power \| 2019 Alternate Rate Plan
Public Utilities, General Disclosures [Line Items]
Retail rate of return on common equity																							9.50%

REGULATORY MATTERS - GPC Fuel C

REGULATORY MATTERS - GPC Fuel Cost and Storm Damage Recovery (Details) - USD ($) $ in Millions			1 Months Ended	6 Months Ended	12 Months Ended	24 Months Ended
	May 16, 2023	Jan. 01, 2023	Nov. 30, 2021	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]
To be recovered amount	$ 2,200
Net regulatory assets					$ 6,523	$ 5,833
Georgia Power
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount			$ 252
Adjustment to fuel cost recovery rate if under recovered fuel balance exceeds budget thereafter				$ 200
Recovery period	3 years
Approved rate increase, percent			15%
Over (under) recovered fuel balance					$ (1,900)	(2,100)
Required period for options and hedges					36 months
Storm damage reserves		$ 31				213
Regulatory liabilities					$ 54	83
Net regulatory assets					5,090	$ 4,663
Requested rate increase (decrease), percentage	54%
Requested rate increase (decrease), amount	$ 1,100
Georgia Power \| Under Recovered Fuel Clause Revenues
Public Utilities, General Disclosures [Line Items]
Over (under) recovered fuel balance					(694)
Georgia Power \| Deferred Under Recovered Fuel Clause Revenues
Public Utilities, General Disclosures [Line Items]
Over (under) recovered fuel balance					(1,200)
Georgia Power \| Other regulatory assets, current
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities					31
Georgia Power \| Other Regulatory Assets
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities					$ 23
Georgia Power \| Maximum
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ 200
Approved rate increase, percent	40%

REGULATORY MATTERS - GPC Nuclea

REGULATORY MATTERS - GPC Nuclear Construction (Details) - Georgia Power $ in Millions			3 Months Ended			12 Months Ended
	Oct. 17, 2023 USD ($)	Oct. 05, 2023 USD ($)	Dec. 31, 2023 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2012 utility MW
Public Utilities, General Disclosures [Line Items]
Number of construction units approved \| utility							2
Electric generating capacity (in MWs) \| MW							1,100
Pre-tax charge to income				$ 160	$ 407	$ 567
After tax charge to income				$ 120	$ 304
Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Percent ownership			45.70%			45.70%
Estimated construction financing costs			$ 3,530			$ 3,530
Construction financing costs incurred to date			3,500			$ 3,500
Pre-tax charge to income			228
After tax charge to income			$ 170
Additional construction capital costs	$ 17	$ 308
Remaining share of construction costs, agreement to pay, percentage		66%				100%
Plant Vogtle Units 3 and 4 \| Oglethorpe Power Corporation
Public Utilities, General Disclosures [Line Items]
Agreement with third party, expected cost		$ 105
Plant Vogtle Units 3 and 4 \| Dalton Utilities
Public Utilities, General Disclosures [Line Items]
Agreement with third party, expected cost	$ 6
Plant Watson Unit 4
Public Utilities, General Disclosures [Line Items]
Additional base capital costs per month (up to)						$ 25

REGULATORY MATTERS - GPC Schedu

REGULATORY MATTERS - GPC Schedule of Nuclear Construction Cost and Schedule (Details) - USD ($) $ in Millions	3 Months Ended			12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Commitments [Line Items]
Total AFUDC and interest capitalized				$ 400	$ 327	$ 282
Georgia Power
Commitments [Line Items]
Pre-tax charge to income		$ 160	$ 407	567
Total AFUDC and interest capitalized				251	$ 213	$ 190
Georgia Power \| Plant Vogtle Units 3 and 4
Commitments [Line Items]
Base project capital cost forecast	$ 10,717			10,717
Construction contingency estimate	36			36
Preliminary estimated cost to complete	10,753			10,753
Net investment	(10,564)			(10,564)
Remaining estimate to complete	189			189
Estimated cost to complete, costs not shared with other owners	610			610
Estimated cost to complete, construction monitoring costs approved for recovery	33			33
Pre-tax charge to income	228
Total AFUDC and interest capitalized				440
Total AFUDC and interest capitalized, accrual amount	$ 417			$ 417

REGULATORY MATTERS - GPC Joint

REGULATORY MATTERS - GPC Joint Ownership Agreements (Details) - USD ($) $ in Millions				1 Months Ended	3 Months Ended			12 Months Ended
	Oct. 17, 2023	Oct. 05, 2023	Sep. 29, 2022	Sep. 30, 2022	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Dec. 31, 2023
Public Utilities, General Disclosures [Line Items]
Agreement with third party, amount of costs over projected forecast to be paid by company			20%
Georgia Power
Public Utilities, General Disclosures [Line Items]
Pre-tax charge to income						$ 160	$ 407	$ 567
After tax charge to income						$ 120	$ 304
Plant Vogtle Units 3 and 4 \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Ownership interest percentage required for voting for continuing construction					90%			90%
Production tax credits, aggregate purchase price (up to)								$ 300
Preliminary estimated cost to complete					$ 10,753			$ 10,753
Additional construction capital costs	$ 17	$ 308
Remaining share of construction costs, agreement to pay, percentage		66%						100%
Percentage of costs, disallowed for recovery								6%
Costs disallowed for recovery, period								6 months
Public utilities, extension project schedule, term								1 year
Pre-tax charge to income					228
After tax charge to income					$ 170
Percent ownership					45.70%			45.70%
Plant Vogtle Units 3 and 4 \| Georgia Power \| MEAG Power
Public Utilities, General Disclosures [Line Items]
Agreement with third party, expected cost				$ 92
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category I
Public Utilities, General Disclosures [Line Items]
Preliminary estimated cost to complete					$ 8,400			$ 8,400
Additional construction capital costs, threshold								800
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category II
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs								$ 80
Percentage of construction costs responsible to pay								55.70%
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category II \| Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay								44.30%
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category II \| Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold								$ 800
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category II \| Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold								1,600
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category III
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs								$ 100
Percentage of construction costs responsible to pay								65.70%
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category III \| Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay								34.30%
Plant Vogtle Units 3 and 4 \| Georgia Power \| Category III \| Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold								$ 2,100

REGULATORY MATTERS - GPC Regula

REGULATORY MATTERS - GPC Regulatory Matters (Details) - USD ($) $ in Millions

1 Months Ended

6 Months Ended

12 Months Ended

Mar. 24, 2024

Oct. 17, 2023

Oct. 05, 2023

Jan. 01, 2021

Jan. 01, 2020

Jan. 01, 2018

Jan. 01, 2016

Dec. 31, 2022

Jun. 30, 2021

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Dec. 31, 2009

Jan. 31, 2018

Dec. 31, 2016

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 5,833

$ 6,523

$ 5,833

Deferred Income Tax Charges

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

866

897

866

Georgia Power

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

4,663

5,090

4,663

Georgia Power | Deferred Income Tax Charges

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

583

605

583

Plant Vogtle Units 3 and 4 | Georgia Power

Public Utilities, General Disclosures [Line Items]

Estimated in-service capital cost

$ 4,418

Proceeds from recovery of financing costs

$ 3,000

Project capital cost forecast

$ 7,300

Requested decrease in NCCR tariff

$ (36)

Additional construction capital costs

$ 17

$ 308

Retail rate of return on common equity

10.95%

Authorized ROE

5.30%

8.30%

10%

Potential decrease each month, percentage

0.10%

Return on equity reduction, negative impact on earnings

$ 310

$ 300

$ 270

Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charge, Debt Component

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charges

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

Plant Vogtle Units 3 and 4 | Georgia Power | Deferred Income Tax Charge, Equity Component

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 23

Plant Vogtle Units 3 and 4 | Georgia Power | Twenty Fifth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Maximum guarantee

$ 1,700

Customer refund

$ 188

Plant Vogtle Units 3 and 4 | Georgia Power | Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Return on equity reduction, negative impact on earnings

$ 30

$ 90

REGULATORY MATTERS - MPC 2019 B

REGULATORY MATTERS - MPC 2019 Base Rate Case and Performance Evaluation Plan (Details) $ in Millions	1 Months Ended				12 Months Ended
	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	May 31, 2021 USD ($)	Dec. 31, 2023 filing	Dec. 31, 2021 USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory asset amortization period					4 years
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount \| $	$ (7)	$ 18	$ 16	$ 28		$ 9
Approved rate decrease, percent		(1.90%)	(1.80%)
Performance evaluation plan, number of filings per calendar year \| filing					2
Mississippi Power \| Weighted Average \| Measurement Input, Average Customer Price
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.40
Mississippi Power \| Weighted Average \| Measurement Input, Service Reliability
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.40
Mississippi Power \| Weighted Average \| Measurement Input, Customer Satisfaction
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.20

REGULATORY MATTERS - MPC Integr

REGULATORY MATTERS - MPC Integrated Resource Plan (Details) $ in Millions	1 Months Ended
	Oct. 31, 2023 MW	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 MW	Dec. 31, 2020 MW
Public Utilities, General Disclosures [Line Items]
Net regulatory assets \| $		$ 6,523	$ 5,833
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs)					950
Net regulatory assets \| $		90	$ 4
Approved additional generating capacity (in MW)	750
Mississippi Power \| Plant Watson Unit 4
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs)				268
Mississippi Power \| Plant Greene County Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs)				103
Percent ownership				40%
Mississippi Power \| Plant Greene County Units 1 and 2 \| Alabama Power
Public Utilities, General Disclosures [Line Items]
Percent ownership				40%
Mississippi Power \| Plant Daniel
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs)				502
Percent ownership				50%
Net regulatory assets \| $		$ 489

REGULATORY MATTERS - MPC Enviro

REGULATORY MATTERS - MPC Environmental Compliance Overview Plan (Details) - Mississippi Power - USD ($) $ in Millions		1 Months Ended						12 Months Ended
	Feb. 12, 2024	Jun. 30, 2023	Apr. 30, 2023	Jun. 30, 2022	Apr. 30, 2022	Jun. 30, 2021	May 31, 2021	Dec. 31, 2021
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount		$ (7)		$ 18		$ 16	$ 28	$ 9
Environmental Compliance Overview Plan
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount			$ 3		$ 1	$ (9)
Environmental Compliance Overview Plan \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ 9

REGULATORY MATTERS - MPC Fuel C

REGULATORY MATTERS - MPC Fuel Cost Recovery and Ad Valorem Tax Adjustment (Details) - Mississippi Power - USD ($) $ in Millions

1 Months Ended

12 Months Ended

Feb. 06, 2024

Jan. 31, 2024

Jun. 30, 2023

Jan. 31, 2023

Nov. 30, 2022

Jul. 31, 2022

Jun. 30, 2022

Feb. 28, 2022

Jan. 31, 2022

Jun. 30, 2021

May 31, 2021

Feb. 28, 2021

Dec. 31, 2021

Dec. 31, 2023

Dec. 31, 2022

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (7)

$ 18

$ 16

$ 28

$ 9

Public utilities, valorem taxes previously recovered, amount

$ 19

Ad Valorem Tax Adjustment

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 5

Retail electric revenues

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 25

$ 43

$ 2

Over (under) recovered fuel cost

$ (50)

$ (1)

Retail electric revenues | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 18

Over (under) recovered fuel cost

$ (61)

MRA Revenue

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 22

$ 11

Over (under) recovered fuel cost

$ (6)

MRA Revenue | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (4)

Retail ECM

Public Utilities, General Disclosures [Line Items]

Over (under) recovered fuel cost

$ 27

REGULATORY MATTERS - MPC System

REGULATORY MATTERS - MPC System Restoration Rider and Department of Revenue Audit (Details) - USD ($)	1 Months Ended				12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021	May 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Feb. 01, 2024	Apr. 04, 2023	Apr. 03, 2023
Public Utilities, General Disclosures [Line Items]
Reliability reserve, amount deferred					$ 63,000,000	$ 191,000,000
Total deferred charges and other assets					19,069,000,000	20,148,000,000
Regulatory asset					66,000,000	216,000,000
Major storms
Public Utilities, General Disclosures [Line Items]
Storm damage reserves accrual						239,000,000	$ 286,000,000
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Threshold above which actual damages are charged to the reserve (individually exceed)					50,000
Public utilities, approved rate increase (decrease), amount	$ (7,000,000)	$ 18,000,000	$ 16,000,000	$ 28,000,000			9,000,000
Reliability reserve, amount deferred					11,000,000	25,000,000			$ 11,700,000	$ 8,300,000
Reliability reserve					36,000,000	25,000,000
Total deferred charges and other assets					887,000,000	828,000,000
Regulatory asset					44,000,000	36,000,000
Mississippi Power \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Reliability reserve, amount deferred								$ 12,600,000
Mississippi Power \| Retail electric revenues
Public Utilities, General Disclosures [Line Items]
Property damage reserve					45,000,000	37,000,000
Mississippi Power \| Major storms
Public Utilities, General Disclosures [Line Items]
Storm damage reserves accrual					$ 11,700,000	$ 6,900,000	$ (1,800,000)

REGULATORY MATTERS - MPC Munici

REGULATORY MATTERS - MPC Municipal and Rural Associations Tariff (Details) - Mississippi Power $ in Millions		1 Months Ended
	Jul. 31, 2023 USD ($)	Jul. 31, 2022 USD ($)	Dec. 31, 2023 MW	Dec. 31, 2022	Aug. 26, 2022
Municipal and Rural Associations Tariff
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 16	$ 23
Refund to customers	$ 6
Cooperative Energy
Public Utilities, General Disclosures [Line Items]
Counterparty's option to decrease services, percentage				2.50%
Power being supplied to counterparty \| MW			390
Counterparty's electricity requirement at MRA delivery points					100%

REGULATORY MATTERS - GAS Schedu

REGULATORY MATTERS - GAS Schedule of Utility Regulation and Rate Design (Details)			1 Months Ended	12 Months Ended
	Nov. 16, 2023	Aug. 28, 2023	Nov. 30, 2021	Dec. 31, 2023	Dec. 31, 2021
Nicor Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE	9.51%		9.75%	9.51%
Atlanta Gas Light
Public Utilities, General Disclosures [Line Items]
Authorized ROE				10.25%
Virginia Natural Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE		9.70%		9.70%	9.50%
Chattanooga Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE				9.80%

REGULATORY MATTERS - GAS Infras

REGULATORY MATTERS - GAS Infrastructure Replacement Programs and Capital Projects (Details) $ in Millions				3 Months Ended	12 Months Ended
	Feb. 09, 2024 USD ($)	Feb. 01, 2024 USD ($)	Nov. 16, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2021 USD ($) mi	Dec. 31, 2019 USD ($)	Dec. 31, 2014	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)
Southern Company Gas
Public Utilities, General Disclosures [Line Items]
Capital expenditures					$ 553
Southern Company Gas \| Natural Gas Cost Under Recovery
Public Utilities, General Disclosures [Line Items]
Over (under) recovered fuel cost				$ (214)	(214)				$ 108
Southern Company Gas \| SAVE
Public Utilities, General Disclosures [Line Items]
Capital expenditures					75
Southern Company Gas \| SAVE \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	$ 355
Program duration period	5 years
Infrastructure replacement program, approved investment variance amount	$ 5
Southern Company Gas \| SAVE \| 2025 \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	70
Southern Company Gas \| SAVE \| 2026 \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	70
Southern Company Gas \| SAVE \| 2027 \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	70
Southern Company Gas \| SAVE \| 2028 \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	70
Southern Company Gas \| SAVE \| 2029 \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year	$ 70
Southern Company Gas \| Investing In Illinois Qualifying Infrastructure Plant
Public Utilities, General Disclosures [Line Items]
Capital expenditures					365
Nicor Gas
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed				69
Nicor Gas \| Regulatory Infrastructure Program
Public Utilities, General Disclosures [Line Items]
Program duration period								9 years
Nicor Gas \| Investing In Illinois Qualifying Infrastructure Plant
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed			$ 126.8		63		$ 32
Capital expenditures							415
Nicor Gas \| Other Transmission and Distribution Capital Investments
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed			$ 95.9
Nicor Gas \| Maximum
Public Utilities, General Disclosures [Line Items]
Infrastructure investment, annual customer rate increase								4%
Infrastructure investment, annual customer rate increase in any given year								5.50%
Virginia Natural Gas \| SAVE
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							$ 365
Program duration period							6 years
Infrastructure replacement program, approved investment variance amount										$ 5
Virginia Natural Gas \| SAVE \| Year 2021
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year										60
Virginia Natural Gas \| SAVE \| Year 2022
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year										70
Virginia Natural Gas \| SAVE \| Year 2023
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year										70
Virginia Natural Gas \| SAVE \| Year 2024
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year										$ 70
Atlanta Gas Light
Public Utilities, General Disclosures [Line Items]
Gain contingency, unrecorded amount				44	44
Annual proceeds from strategic economic development projects					15
Approved annual recovery of capital investment						$ 286
Atlanta Gas Light \| True-Up Recovery, Unrecognized Equity
Public Utilities, General Disclosures [Line Items]
Gain contingency, unrecorded amount				$ 23	23
Atlanta Gas Light \| Maximum \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved annual recovery of capital investment		$ 1,000
Atlanta Gas Light \| Minimum \| Subsequent Event
Public Utilities, General Disclosures [Line Items]
Approved annual recovery of capital investment		$ 700
Chattanooga Gas
Public Utilities, General Disclosures [Line Items]
Program duration period						7 years
Pipeline replacement program, length of distribution main \| mi						73
Preliminary estimated cost to complete						$ 118
Operating Segments \| Gas distribution operations \| Southern Company Gas
Public Utilities, General Disclosures [Line Items]
Gross property additions					$ 1,600

REGULATORY MATTERS - GAS Sche_2

REGULATORY MATTERS - GAS Schedule of Infrastructure Replacement Programs and Capital Projects (Details) - Southern Company Gas $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) mi	Dec. 31, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Capital Expenditures in 2023	$ 553
Capital Expenditures Since Project Inception	$ 3,910
Pipe Installed Since Project Inception (in miles) \| mi	1,969
Scope of Program (in miles) \| mi	2,135
Investing In Illinois Qualifying Infrastructure Plant
Public Utilities, General Disclosures [Line Items]
Capital Expenditures in 2023	$ 365
Capital Expenditures Since Project Inception	$ 3,228
Pipe Installed Since Project Inception (in miles) \| mi	1,367
Scope of Program (in miles) \| mi	1,367
Program Duration	9 years
SAVE
Public Utilities, General Disclosures [Line Items]
Capital Expenditures in 2023	$ 75
Capital Expenditures Since Project Inception	$ 486
Pipe Installed Since Project Inception (in miles) \| mi	567
Scope of Program (in miles) \| mi	695
Program Duration	13 years
System Reinforcement Rider
Public Utilities, General Disclosures [Line Items]
Capital Expenditures in 2023	$ 104	$ 76
Capital Expenditures Since Project Inception	$ 180
Pipe Installed Since Project Inception (in miles) \| mi	20
Program Duration	3 years
Pipeline Replacement Program
Public Utilities, General Disclosures [Line Items]
Capital Expenditures in 2023	$ 9
Capital Expenditures Since Project Inception	$ 16
Pipe Installed Since Project Inception (in miles) \| mi	15
Scope of Program (in miles) \| mi	73
Program Duration	7 years

REGULATORY MATTERS - GAS Infr_2

REGULATORY MATTERS - GAS Infrastructure Replacement Programs and Capital Projects Schedule of QIP (Details) - Nicor Gas - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Nov. 16, 2023	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2019
Commitments [Line Items]
Disallowed		$ 69
Investing In Illinois Qualifying Infrastructure Plant
Commitments [Line Items]
Capital Investments			$ 3,228
Disallowed	$ 126.8		63	$ 32
Investing In Illinois Qualifying Infrastructure Plant \| Complete
Commitments [Line Items]
Capital Investments			1,246
Disallowed			0
Investing In Illinois Qualifying Infrastructure Plant \| Complete(a)
Commitments [Line Items]
Capital Investments			415
Disallowed			32
Investing In Illinois Qualifying Infrastructure Plant \| Filed March 2021
Commitments [Line Items]
Capital Investments			402
Disallowed
Investing In Illinois Qualifying Infrastructure Plant \| Filed March 2022
Commitments [Line Items]
Capital Investments			392
Disallowed
Investing In Illinois Qualifying Infrastructure Plant \| Filed March 2023
Commitments [Line Items]
Capital Investments			408
Disallowed			6
Investing In Illinois Qualifying Infrastructure Plant \| To be filed by March 20, 2024
Commitments [Line Items]
Capital Investments			365
Disallowed			$ 25

REGULATORY MATTERS - GAS Rate P

REGULATORY MATTERS - GAS Rate Proceedings and Deferral of Incremental COVID-19 Costs (Details) - USD ($) $ in Millions

1 Months Ended

12 Months Ended

Feb. 01, 2024

Jan. 01, 2024

Nov. 16, 2023

Aug. 28, 2023

Jan. 01, 2023

Jan. 01, 2022

Nov. 01, 2020

Nov. 30, 2021

Apr. 30, 2021

Dec. 31, 2024

Dec. 31, 2023

Dec. 31, 2022

Dec. 31, 2021

Feb. 09, 2024

Dec. 31, 2019

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 6,523

$ 5,833

Nicor Gas

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 223

$ 240

Authorized ROE

9.51%

9.75%

9.51%

Public utilities, approved equity capital structure, percentage

50%

54.50%

Nicor Gas | Investing In Illinois Qualifying Infrastructure Plant

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase amount recovery of investments

$ 94

Atlanta Gas Light

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (43)

$ (7)

(5)

Authorized ROE

10.25%

Public utilities, maximum base rate percentage

Integrated capacity delivery plan, capital budgets and related operations and maintenance spending, term

10 years

Approved rate decrease, percent

10%

Integrated capacity delivery plan, capital forecast plan, years one through three

$ 1,700

Approved annual recovery of capital investment

$ 286

Atlanta Gas Light | Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (9)

Atlanta Gas Light | Minimum

Public Utilities, General Disclosures [Line Items]

Authorized ROE

10.05%

Integrated capacity delivery plan, capital forecast plan, years one through ten

$ 500

Atlanta Gas Light | Minimum | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Approved annual recovery of capital investment

$ 700

Atlanta Gas Light | Maximum

Public Utilities, General Disclosures [Line Items]

Authorized ROE

10.45%

Integrated capacity delivery plan, capital forecast plan, years one through ten

$ 600

Atlanta Gas Light | Maximum | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Approved annual recovery of capital investment

$ 1,000

Virginia Natural Gas

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 48

Public utilities, approved rate increase amount recovery of investments

$ 14

Authorized ROE

9.70%

9.50%

Public utilities, approved equity capital structure, percentage

49.06%

51.90%

Requested rate increase (decrease), amount

$ 69

$ 50

Virginia Natural Gas | SAVE

Public Utilities, General Disclosures [Line Items]

Approved infrastructure replacement program, approved investment amount, current fiscal year

$ 365

Southern Company Gas

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease), amount

$ 53

Net regulatory assets

$ (2,225)

$ (1,891)

Southern Company Gas | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease), amount

$ 53

Southern Company Gas | SAVE | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Approved infrastructure replacement program, approved investment amount, current fiscal year

$ 355

Southern Company Gas | SAVE | Subsequent Event | 2025

Public Utilities, General Disclosures [Line Items]

Approved infrastructure replacement program, approved investment amount, current fiscal year

$ 70

REGULATORY MATTERS - GAS Sche_3

REGULATORY MATTERS - GAS Schedule of Unrecognized Ratemaking Amounts (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	$ 66	$ 216
Regulatory Asset Off Balance Sheet \| Atlanta Gas Light
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	23	35
Regulatory Asset Off Balance Sheet \| Virginia Natural Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	10	10
Regulatory Asset Off Balance Sheet \| Chattanooga Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	7	2
Regulatory Asset Off Balance Sheet \| Nicor Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	3	3
Regulatory Asset Off Balance Sheet \| Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	$ 43	$ 50

REGULATORY MATTERS - GAS (Detai

REGULATORY MATTERS - GAS (Details) - USD ($) $ in Millions		3 Months Ended		12 Months Ended
REGULATORY MATTERS - GAS (Details) - USD ($) $ in Millions	Nov. 16, 2023	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Revenues				$ (25,253)	$ (29,279)	$ (23,113)
Total operating expenses				19,427	$ 23,909	$ 19,415
Nicor Gas
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed		$ 69
Pretax charge to income		58	$ 38	(96)
After tax charge to income		$ 44	28	(72)
Investing In Illinois Qualifying Infrastructure Plant \| Nicor Gas
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed	$ 126.8			$ 63			$ 32
Capital expenditures							$ 415
Revenues			8
Total operating expenses			$ 30
QIP Rider \| Nicor Gas
Public Utilities, General Disclosures [Line Items]
Infrastructure disallowed	$ 31

CONTINGENCIES, COMMITMENTS, A_3

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - SO Litigation (Details) - Kemper County energy facility assets, net - Mississippi Power - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2010
Loss Contingencies [Line Items]
Government grants expected		$ 137	$ 270
Government grants received	$ 387

CONTINGENCIES, COMMITMENTS, A_4

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GPC Litigation (Details) - claim	1 Months Ended
	Jan. 31, 2023	Feb. 28, 2022	Oct. 31, 2021
Class Action Lawsuit \| Pending Litigation \| Georgia Power
Loss Contingencies [Line Items]
Number of additional complaints filed	8	8	8

CONTINGENCIES, COMMITMENTS, A_5

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC Litigation (Details) - Purported Violations Of Mississippi Consumer Protection Act - Pending Litigation - Mississippi Power $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2019 plaintiff	Dec. 31, 2018 USD ($) defendant plaintiff
Schedule of Regulatory Assets and Liabilities [Line Items]
Number of plaintiffs \| plaintiff	4	10
Loss contingency, number of defendants \| defendant		3
Public utilities, underpayment of refunds \| $		$ 23.5

CONTINGENCIES, COMMITMENTS, A_6

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - SPC Litigation (Details) $ in Millions	1 Months Ended	12 Months Ended
	Jul. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jul. 31, 2021 project
Loss Contingencies [Line Items]
Total operating revenues		$ 25,253	$ 29,279	$ 23,113
Net loss attributable to noncontrolling interests		(127)	(107)	(99)
Other revenues
Loss Contingencies [Line Items]
Total operating revenues		949	732	708
Southern Power
Loss Contingencies [Line Items]
Total operating revenues		2,189	3,369	2,216
Net loss attributable to noncontrolling interests		(127)	(107)	(99)
Southern Power \| Other revenues
Loss Contingencies [Line Items]
Total operating revenues		55	$ 36	$ 30
Southern Power \| Southern Power vs First Solar \| Settled Litigation
Loss Contingencies [Line Items]
Number of solar projects \| project					5
Proceeds from legal settlements	$ 36
Litigation settlement		18
Decrease in operating expense, maintenance and operations		11
Net loss attributable to noncontrolling interests		6
Southern Power \| Southern Power vs First Solar \| Settled Litigation \| Other revenues
Loss Contingencies [Line Items]
Total operating revenues		$ 7

CONTINGENCIES, COMMITMENTS, A_7

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Environmental Remediation (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) site state	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Georgia Power
Environmental Exit Cost [Line Items]
Costs recovered annually	$ 5,000,000	$ 12,000,000	$ 12,000,000
Environmental remediation liability, current	14,000,000	15,000,000
Accrued environmental remediation	0	0
Under recovered environmental remediation costs, other regulatory assets, current	5,000,000	5,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred	15,000,000	20,000,000
Southern Company Gas
Environmental Exit Cost [Line Items]
Environmental remediation liability, current	30,000,000	49,000,000
Accrued environmental remediation	192,000,000	207,000,000
Under recovered environmental remediation costs, other regulatory assets, current	40,000,000	54,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred	$ 195,000,000	215,000,000
Southern Company Gas \| Manufactured Gas Plants
Environmental Exit Cost [Line Items]
Number of sites \| site	40
Number of states in which subject to environmental remediation liabilities \| state	4
Alabama Power
Environmental Exit Cost [Line Items]
Environmental remediation liability, current	$ 0	0
Southern Company
Environmental Exit Cost [Line Items]
Environmental remediation liability, current	44,000,000	65,000,000
Accrued environmental remediation	192,000,000	207,000,000
Under recovered environmental remediation costs, other regulatory assets, current	45,000,000	59,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred	$ 210,000,000	$ 235,000,000
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current

CONTINGENCIES, COMMITMENTS, A_8

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Nuclear Fuel Disposal Costs and Nuclear Insurance (Details) $ in Millions	12 Months Ended	108 Months Ended
	Dec. 31, 2023 USD ($) plant	Dec. 31, 2019 USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Maximum fund for public liability claims arising from a single nuclear incident under price - anderson amendments act	$ 16,200
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant	450
Maximum amount that a company could be assessed per incident for each licensed reactor	166
Maximum aggregate amount that a reactor can assess in a calendar period for each incident	$ 25
Block period considered for inflation adjustment against maximum assessment per reactor	5 years
Maximum deductible waiting period	182 days
Maximum coverage per occurrence per unit limit to obtain replacement power	$ 490
Aggregate payment for claims resulting from terrorist acts in one year period	3,200
Vogtle Units 3 and 4
Jointly Owned Utility Plant Interests [Line Items]
Maximum limits for accidental property damage occurring during construction	$ 2,750
Alabama Power and Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Number of nuclear fuel plants \| plant	3
Maximum property damage insurance provided to nuclear generating facilities	$ 1,500
Maximum additional coverage provided for losses under excess insurance	1,250
Maximum additional coverage provided for losses under excess insurance, non-nuclear losses	$ 750
Elected deductible waiting period	84 days
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Maximum assessment, excluding any applicable state premium taxes	$ 332
Maximum aggregate amount to be paid in one year	49
Current maximum annual assessments under NEIL policies	54
Alabama Power \| Positive Outcome of Litigation
Jointly Owned Utility Plant Interests [Line Items]
Outstanding claims		$ 106
Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Maximum assessment, excluding any applicable state premium taxes	473
Maximum aggregate amount to be paid in one year	71
Current maximum annual assessments under NEIL policies	$ 89
Georgia Power \| Positive Outcome of Litigation
Jointly Owned Utility Plant Interests [Line Items]
Outstanding claims		$ 128

CONTINGENCIES, COMMITMENTS, A_9

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - APC Litigation (Details) - Alabama Power - AT&T $ in Millions	1 Months Ended
	Apr. 30, 2019 USD ($)
Loss Contingencies [Line Items]
Potential refund amount owed	$ 87
Refund payment period	6 years

CONTINGENCIES, COMMITMENTS, _10

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC Other Matters (Details)	12 Months Ended				60 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2025 USD ($)	Jan. 15, 2024 USD ($)	Jul. 30, 2022 claim
Loss Contingencies [Line Items]
Period costs	$ 90,000,000	$ 36,000,000
Mississippi Power
Loss Contingencies [Line Items]
Period costs	0	0
Kemper County energy facility assets, net \| Mississippi Power
Loss Contingencies [Line Items]
Pre-tax charge to income	17,000,000	15,000,000	$ 11,000,000
After tax charge to income	$ 12,000,000	$ 12,000,000	$ 8,000,000
Plant Daniel \| Mississippi Power
Loss Contingencies [Line Items]
Plant units \| claim							2
Plant Daniel Unit, Primary \| Mississippi Power
Loss Contingencies [Line Items]
Plant units \| claim							1
Scenario, Forecast \| Kemper County energy facility assets, net \| Mississippi Power \| Maximum
Loss Contingencies [Line Items]
Period costs					$ 15,000,000
Scenario, Forecast \| Plant Daniel \| Mississippi Power
Loss Contingencies [Line Items]
Payments to acquire businesses						$ 1
Scenario, Forecast \| Plant Daniel \| Gulf Power
Loss Contingencies [Line Items]
Percent ownership in individual unit						100%
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Gulf Power
Loss Contingencies [Line Items]
Proceeds from divestiture of businesses, amount held back				$ 75,000,000

CONTINGENCIES, COMMITMENTS, _11

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Commitments (Details) - Georgia Power - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
MEAG Power
Loss Contingencies [Line Items]
Percent ownership	5%
Plant Vogtle Units 1 and 2
Loss Contingencies [Line Items]
Capacity payments	$ 3	$ 4	$ 6
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
Total	39
Recorded unconditional purchase obligation, year one	4
Recorded unconditional purchase obligation, year two	4
Recorded unconditional purchase obligation, year three	2
Recorded unconditional purchase obligation, year four	2
Recorded unconditional purchase obligation, year five	2
Recorded unconditional purchase obligation, after year five	$ 25

CONTINGENCIES, COMMITMENTS, _12

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GAS Commitments (Details) - Southern Company Gas MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) MMBTU
Long-term Purchase Commitment [Line Items]
Natural gas pipeline capacity \| MMBTU	38
Long-term purchase commitment amount	$ 98
Pipeline Charges, Storage Capacity, and Gas Supply
Pipeline Charges, Storage Capacity, and Gas Supply
2024	587
2025	432
2026	231
2027	148
2028	103
Thereafter	785
Total	$ 2,286

CONTINGENCIES, COMMITMENTS, _13

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Guarantees (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Recorded Unconditional Purchase Obligation [Line Items]
Notes payable	$ 2,314	$ 2,609
Alabama Power
Recorded Unconditional Purchase Obligation [Line Items]
Jointly owned affiliate equity	69
Jointly owned affiliate long term debt	100
Notes payable	40	$ 0
SEGCO \| Alabama Power
Recorded Unconditional Purchase Obligation [Line Items]
Guarantee of unsecured senior notes	100
Notes payable	$ 0

REVENUE FROM CONTRACTS WITH C_3

REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregate Revenue Sources (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 24,828	$ 25,941	$ 23,463
Total operating revenues	25,253	29,279	23,113
Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,894	15,839	14,244
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,309	6,604	6,207
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,860	5,369	4,877
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,613	3,764	3,067
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	112	102	93
Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,039	5,218	3,625
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,981	2,843	1,799
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	505	763	470
Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,184	1,186	1,038
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	45	84	49
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	324	342	269
Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,981	3,120	1,851
PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,107	2,274	1,122
PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	624	596	493
Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	250	250	236
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	31	687	2,668
Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			2,168
Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	528	636	464
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	559	51	36
Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,355	1,077	1,075
Other revenue sources
Disaggregation of Revenue [Line Items]
Other	425	3,338	3,349
Other adjustments
Disaggregation of Revenue [Line Items]
Other			(3,699)
Alabama Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	7,233	6,921	6,141
Total operating revenues	7,050	7,817	6,413
Alabama Power \| Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,565	5,844	5,470
Alabama Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,904	2,638	2,467
Alabama Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,928	1,685	1,600
Alabama Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,721	1,507	1,386
Alabama Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	12	14	17
Alabama Power \| Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	455	883	469
Alabama Power \| PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	234	489	184
Alabama Power \| PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	156	194	115
Alabama Power \| Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	65	200	170
Alabama Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			0
Alabama Power \| Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power \| Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	213	194	202
Alabama Power \| Other revenue sources
Disaggregation of Revenue [Line Items]
Other	(183)	896	272
Alabama Power \| Other adjustments
Disaggregation of Revenue [Line Items]
Other			0
Georgia Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	10,129	9,702	8,563
Total operating revenues	10,118	11,584	9,260
Georgia Power \| Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,378	9,049	7,940
Georgia Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,105	3,664	3,471
Georgia Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,624	3,385	3,010
Georgia Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,558	1,921	1,391
Georgia Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	91	79	68
Georgia Power \| Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	173	207	171
Georgia Power \| PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	87	130	95
Georgia Power \| PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51	47	55
Georgia Power \| Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	35	30	21
Georgia Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			0
Georgia Power \| Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power \| Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	578	446	452
Georgia Power \| Other revenue sources
Disaggregation of Revenue [Line Items]
Other	(11)	1,882	697
Georgia Power \| Other adjustments
Disaggregation of Revenue [Line Items]
Other			0
Mississippi Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,462	1,703	1,282
Total operating revenues	1,474	1,694	1,322
Mississippi Power \| Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	951	946	834
Mississippi Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	300	302	269
Mississippi Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	308	299	267
Mississippi Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	334	336	290
Mississippi Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9	9	8
Mississippi Power \| Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	472	710	417
Mississippi Power \| PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	20	16	11
Mississippi Power \| PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	45	4	5
Mississippi Power \| Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	407	690	401
Mississippi Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			0
Mississippi Power \| Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power \| Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	39	47	31
Mississippi Power \| Other revenue sources
Disaggregation of Revenue [Line Items]
Other	12	(9)	40
Mississippi Power \| Other adjustments
Disaggregation of Revenue [Line Items]
Other			0
Southern Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,630	2,805	1,605
Total operating revenues	2,189	3,369	2,216
Southern Power \| Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,575	2,769	1,575
Southern Power \| PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	790	1,673	854
Southern Power \| PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	376	356	323
Southern Power \| Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	409	740	398
Southern Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			0
Southern Power \| Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power \| Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	55	36	30
Southern Power \| Other revenue sources
Disaggregation of Revenue [Line Items]
Other	559	564	611
Southern Power \| Other adjustments
Disaggregation of Revenue [Line Items]
Other			0
Southern Company Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,598	5,905	6,293
Total operating revenues	4,702	5,962	4,380
Southern Company Gas \| Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4,039	5,218	3,625
Southern Company Gas \| Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,981	2,843	1,799
Southern Company Gas \| Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	505	763	470
Southern Company Gas \| Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,184	1,186	1,038
Southern Company Gas \| Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	45	84	49
Southern Company Gas \| Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	324	342	269
Southern Company Gas \| Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	559	687	2,668
Southern Company Gas \| Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers			2,168
Southern Company Gas \| Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	528	636	464
Southern Company Gas \| Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	31	51	36
Southern Company Gas \| Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas \| Other revenue sources
Disaggregation of Revenue [Line Items]
Other	$ 104	$ 57	1,786
Southern Company Gas \| Other adjustments
Disaggregation of Revenue [Line Items]
Other			$ (3,699)

REVENUE FROM CONTRACTS WITH C_4

REVENUE FROM CONTRACTS WITH CUSTOMERS - Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 2,820	$ 3,123
Contract Assets	271	156
Contract Liabilities	116	45
Contract with customer, liability, revenue recognized	36	36
Unregulated Distributed Generation
Disaggregation of Revenue [Line Items]
Contract Assets	91	65
Contract Liabilities	115	32
Alabama Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	821	696
Contract Assets	2	2
Contract Liabilities	0	4
Georgia Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	1,011	922
Contract Assets	121	89
Contract Liabilities	1	9
Mississippi Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	90	92
Contract Assets	0	0
Contract Liabilities	0	0
Southern Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	122	237
Contract Assets	0	0
Contract Liabilities	4	1
Southern Company Gas
Disaggregation of Revenue [Line Items]
Accounts Receivable	684	1,107
Contract Assets	56	0
Contract Liabilities	0	$ 0
Southern Company Gas \| Energy Efficiency Enhancement And Upgrade
Disaggregation of Revenue [Line Items]
Contract Liabilities	$ 59

REVENUE FROM CONTRACTS WITH C_5

REVENUE FROM CONTRACTS WITH CUSTOMERS - Performance Obligations (Details) $ in Millions	Dec. 31, 2023 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 940
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 552
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 338
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 332
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 323
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 2,045
Expected timing of satisfaction
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 23
Expected timing of satisfaction	1 year
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 9
Expected timing of satisfaction	1 year
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Alabama Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 73
Expected timing of satisfaction	1 year
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 41
Expected timing of satisfaction	1 year
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 14
Expected timing of satisfaction	1 year
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 15
Expected timing of satisfaction	1 year
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 15
Expected timing of satisfaction	1 year
Georgia Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 9
Expected timing of satisfaction
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 60
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	63
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	66
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	69
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	73
Mississippi Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	0
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 379
Expected timing of satisfaction	1 year
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 301
Expected timing of satisfaction	1 year
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 299
Expected timing of satisfaction	1 year
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 306
Expected timing of satisfaction	1 year
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 297
Expected timing of satisfaction	1 year
Southern Power \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 2,041
Expected timing of satisfaction
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 26
Expected timing of satisfaction	1 year
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas \| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2029-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction

PROPERTY, PLANT, AND EQUIPMEN_2

PROPERTY, PLANT, AND EQUIPMENT - Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Electric utilities:
Generation	$ 57,325	$ 51,756
Transmission	15,561	14,201
Distribution	26,482	24,200
General/other	6,305	5,806
Electric utilities' plant in service	105,673	95,963
Southern Company Gas:
Natural gas transportation and distribution	17,798	16,810
Storage facilities	1,565	1,553
Other	1,477	1,360
Southern Company Gas plant in service	20,840	19,723
Other plant in service	1,915	1,843
Total plant in service	128,428	117,529
Alabama Power
Electric utilities:
Generation	16,584	15,920
Transmission	6,152	5,658
Distribution	9,775	9,154
General/other	2,918	2,740
Electric utilities' plant in service	35,429	33,472
Southern Company Gas:
Natural gas transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	35,429	33,472
Georgia Power
Electric utilities:
Generation	22,587	17,755
Transmission	8,402	7,576
Distribution	15,380	13,819
General/other	3,001	2,729
Electric utilities' plant in service	49,370	41,879
Southern Company Gas:
Natural gas transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	49,370	41,879
Mississippi Power
Electric utilities:
Generation	2,909	2,826
Transmission	966	927
Distribution	1,327	1,228
General/other	321	273
Electric utilities' plant in service	5,523	5,254
Southern Company Gas:
Natural gas transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	5,523	5,254
Southern Power
Electric utilities:
Generation	14,649	14,619
Transmission	0	0
Distribution	0	0
General/other	41	39
Electric utilities' plant in service	14,690	14,658
Southern Company Gas:
Natural gas transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	14,690	14,658
Southern Company Gas
Electric utilities:
Generation	0	0
Transmission	0	0
Distribution	0	0
General/other	0	0
Electric utilities' plant in service	0	0
Southern Company Gas:
Natural gas transportation and distribution	17,798	16,810
Storage facilities	1,565	1,553
Other	1,477	1,360
Southern Company Gas plant in service	20,840	19,723
Other plant in service	0	0
Total plant in service	$ 20,840	$ 19,723

PROPERTY, PLANT, AND EQUIPMEN_3

PROPERTY, PLANT, AND EQUIPMENT - Additional Information (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	4 years
Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	$ 46	$ 29	$ 0
Alabama Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	11	8	0
Georgia Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	19	12	0
Southern Company Gas \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	8	0	0
SOUTHERN POWER CO \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	0	0	0
Mississippi Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Amortization	$ 0	$ 0	$ 0
Plant Farley \| Alabama Power \| Nuclear Outage
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months
Plant Hatch Units 1 and 2 \| Georgia Power \| Nuclear Outage \| Maximum
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	24 months
Plant Vogtle Nuclear Units One , Two, and Three \| Georgia Power \| Nuclear Outage
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months

PROPERTY, PLANT, AND EQUIPMEN_4

PROPERTY, PLANT, AND EQUIPMENT - Deferred Cloud Implementation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	$ 19,069	$ 20,148
Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	325	345
Amortization	46	29	$ 0
Alabama Power
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	5,090	5,372
Alabama Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	85	81
Amortization	11	8	0
Georgia Power
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	10,200	11,117
Georgia Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	99	108
Amortization	19	12	0
Mississippi Power
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	887	828
Mississippi Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	13	14
Amortization	0	0	0
Southern Power
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	998	956
Southern Power \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	15	18
Amortization	0	0	0
Southern Company Gas
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	890	882
Southern Company Gas \| Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Total deferred charges and other assets	43	54
Amortization	$ 8	$ 0	$ 0

PROPERTY, PLANT, AND EQUIPMEN_5

PROPERTY, PLANT, AND EQUIPMENT - Composite Straight-Line Rates (Details) - Utility plant in service	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Alabama Power
Property, Plant and Equipment [Line Items]
Composite rate	4.10%	2.70%	2.70%
Georgia Power
Property, Plant and Equipment [Line Items]
Composite rate	3.80%	3.30%	3.30%
Mississippi Power
Property, Plant and Equipment [Line Items]
Composite rate	3.40%	3.40%	3.60%
Southern Company Gas
Property, Plant and Equipment [Line Items]
Composite rate	2.70%	2.70%	2.80%

PROPERTY, PLANT, AND EQUIPMEN_6

PROPERTY, PLANT, AND EQUIPMENT - Depreciation and Amortization (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 37,725	$ 35,297
Utility plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	36,600	34,300
Other plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 1,100	1,000
Other plant in service \| Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	30 years
Southern Company Gas
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 5,534	5,276
Southern Company Gas \| Utility plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	5,300	5,100
Southern Company Gas \| Other plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 210	$ 184
Southern Company Gas \| Transportation equipment \| Minimum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	5 years
Southern Company Gas \| Transportation equipment \| Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	12 years
Southern Company Gas \| Storage facilities \| Minimum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	30 years
Southern Company Gas \| Storage facilities \| Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	75 years
Southern Company Gas \| Other assets \| Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	75 years

PROPERTY, PLANT, AND EQUIPMEN_7

PROPERTY, PLANT, AND EQUIPMENT - Southern Power Useful Lives (Details) - Southern Power - Maximum	Dec. 31, 2023
Natural Gas Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	50 years
Solar Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	35 years
Wind Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	35 years

PROPERTY, PLANT, AND EQUIPMEN_8

PROPERTY, PLANT, AND EQUIPMENT - Ownership and Investment in Jointly-Owned Facilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) mi
Alabama Power
Other Ownership Interests [Line Items]
Percent Ownership	14%
Alabama Power \| Greene County (natural gas) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	60%
Plant in Service	$ 191
Accumulated Depreciation	113
CWIP	$ 1
Alabama Power \| Plant Miller (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	91.80%
Plant in Service	$ 2,156
Accumulated Depreciation	778
CWIP	$ 40
Georgia Power \| Plant Hatch (nuclear) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	50.10%
Plant in Service	$ 1,446
Accumulated Depreciation	659
CWIP	$ 70
Georgia Power \| Plant Vogtle (nuclear) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	45.70%
Plant in Service	$ 3,664
Accumulated Depreciation	2,331
CWIP	$ 62
Georgia Power \| Plant Vogtle (nuclear) Units 3 and 4
Other Ownership Interests [Line Items]
Percent Ownership	45.70%
Plant in Service	$ 4,613
Accumulated Depreciation	19
CWIP	$ 3,232
Georgia Power \| Plant Scherer (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	8.40%
Plant in Service	$ 287
Accumulated Depreciation	123
CWIP	$ 2
Georgia Power \| Plant Scherer (coal) Unit 3
Other Ownership Interests [Line Items]
Percent Ownership	75%
Plant in Service	$ 1,310
Accumulated Depreciation	639
CWIP	$ 10
Georgia Power \| Rocky Mountain (pumped storage)
Other Ownership Interests [Line Items]
Percent Ownership	25.40%
Plant in Service	$ 181
Accumulated Depreciation	153
CWIP	$ 0
Mississippi Power \| Greene County (natural gas) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	40%
Plant in Service	$ 125
Accumulated Depreciation	80
CWIP	$ 0
Mississippi Power \| Plant Daniel (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	50%
Plant in Service	$ 805
Accumulated Depreciation	281
CWIP	$ 1
Southern Company Gas \| Dalton Pipeline (natural gas pipeline)
Other Ownership Interests [Line Items]
Percent Ownership	50%
Plant in Service	$ 271
Accumulated Depreciation	27
CWIP	$ 0
Pipeline infrastructure (miles) \| mi	115
Agreement to lease undivided ownership (percent)	50%
Future minimum payments receivable	$ 26

PROPERTY, PLANT, AND EQUIPMEN_9

PROPERTY, PLANT, AND EQUIPMENT - Assets Subject to Lien (Narrative) (Details) $ in Millions	Dec. 31, 2023 USD ($)
Mississippi Power \| Chevron
Property, Plant and Equipment [Line Items]
Net book value of co-generation assets	$ 147

ASSET RETIREMENT OBLIGATIONS -

ASSET RETIREMENT OBLIGATIONS - Details of AROs Included in the Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	$ 10,840	$ 11,687
Liabilities incurred	90	36
Liabilities settled	(617)	(455)
Accretion expense	403	406
Cash flow revisions	(399)	(834)
Balance at end of year	10,317	10,840
Alabama Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	4,287	4,334
Liabilities incurred	0	0
Liabilities settled	(270)	(205)
Accretion expense	156	158
Cash flow revisions	(15)	0
Balance at end of year	4,158	4,287
Georgia Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	6,034	6,824
Liabilities incurred	90	35
Liabilities settled	(304)	(212)
Accretion expense	230	231
Cash flow revisions	(385)	(844)
Balance at end of year	5,665	6,034
Mississippi Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	179	190
Liabilities incurred	0	0
Liabilities settled	(18)	(20)
Accretion expense	5	6
Cash flow revisions	2	3
Balance at end of year	168	179
Southern Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	144	131
Liabilities incurred	0	0
Liabilities settled	0	0
Accretion expense	6	6
Cash flow revisions	0	7
Balance at end of year	$ 150	$ 144

ASSET RETIREMENT OBLIGATIONS _2

ASSET RETIREMENT OBLIGATIONS - Narrative (Details)		1 Months Ended				12 Months Ended
ASSET RETIREMENT OBLIGATIONS - Narrative (Details)	Aug. 01, 2023 USD ($)	Nov. 30, 2023 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($) ashPond	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) ashPond	Dec. 31, 2019 USD ($)	Feb. 14, 2024 USD ($)	Mar. 06, 2023 USD ($)	Dec. 31, 2021 USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Revision to ARO						$ (399,000,000)	$ (834,000,000)
Asset retirement obligations					$ 10,840,000,000	10,317,000,000	10,840,000,000				$ 11,687,000,000
Plant Vogtle Units 3 and 4
Jointly Owned Utility Plant Interests [Line Items]
Asset retirement obligations										$ 90,000,000
Plant Vogtle Unit 4 \| Scenario, Forecast
Jointly Owned Utility Plant Interests [Line Items]
Asset retirement obligations									$ 118,000,000
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Revision to ARO						(15,000,000)	0
Asset retirement obligations					4,287,000,000	$ 4,158,000,000	4,287,000,000				4,334,000,000
Asset Retirement Obligation, Period Increase (Decrease)				$ 15,000,000
Estimated inflation rate						4.50%
Estimated trust earnings rate						7%
Alabama Power \| Internal reserves
Jointly Owned Utility Plant Interests [Line Items]
Accumulated provisions for decommissioning					$ 14,000,000	$ 13,000,000	14,000,000
Alabama Power \| Plant Farley
Jointly Owned Utility Plant Interests [Line Items]
Site-specific estimate of decommissioning costs, period of updates made						5 years
Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Revision to ARO						$ (385,000,000)	$ (844,000,000)
Number of ash ponds \| ashPond					1		1
Asset retirement obligations					$ 6,034,000,000	$ 5,665,000,000	$ 6,034,000,000				6,824,000,000
Asset Retirement Obligation, Period Increase (Decrease)		$ 210,000,000	$ 175,000,000
Estimated inflation rate						2.50%
Estimated trust earnings rate						4.50%
Georgia Power \| CCR AROs
Jointly Owned Utility Plant Interests [Line Items]
Revision to ARO					(780,000,000)
Georgia Power \| Plant Hatch and Plant Vogtle Units 1 And 2
Jointly Owned Utility Plant Interests [Line Items]
Annual decommissioning cost for ratemaking							0	$ 4,000,000
Georgia Power \| Plant Vogtle Units 3 and 4
Jointly Owned Utility Plant Interests [Line Items]
Estimated inflation rate						2.40%
Estimated trust earnings rate						4.40%
Annual decommissioning cost for ratemaking	$ 8,000,000
Mississippi Power
Jointly Owned Utility Plant Interests [Line Items]
Revision to ARO						$ 2,000,000	3,000,000
Asset retirement obligations					$ 179,000,000	$ 168,000,000	$ 179,000,000				$ 190,000,000

ASSET RETIREMENT OBLIGATIONS _3

ASSET RETIREMENT OBLIGATIONS - Investment Securities in the Funds (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Marketable Securities [Line Items]
Total investment securities in the Funds	$ 2,422	$ 2,143
Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	1,288	1,095
Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	895	838
Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	239	210
Alabama Power
Marketable Securities [Line Items]
Total investment securities in the Funds	1,259	1,125
Alabama Power \| Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	796	690
Alabama Power \| Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	277	267
Alabama Power \| Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	186	168
Georgia Power
Marketable Securities [Line Items]
Total investment securities in the Funds	1,163	1,018
Fair market value of securities on loan and pledged to creditors		35
Fair value of collateral received		36
Georgia Power \| Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	492	405
Georgia Power \| Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	618	571
Georgia Power \| Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	$ 53	$ 42

ASSET RETIREMENT OBLIGATIONS _4

ASSET RETIREMENT OBLIGATIONS - Fair Value Increases (Decreases) of the Funds (Details) - Securities held in the Funds - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	$ 281	$ (360)	$ 274
Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	241	(391)	(27)
Alabama Power \| Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	157	(171)	200
Alabama Power \| Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	119	(204)	(30)
Georgia Power \| Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	124	(189)	74
Georgia Power \| Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	$ 122	$ (187)	$ 3

ASSET RETIREMENT OBLIGATIONS _5

ASSET RETIREMENT OBLIGATIONS - Accumulated Provisions for the External Decommissioning Trust Funds (Details) - External decommissioning trust funds - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 1,163	$ 1,018
Plant Farley \| Alabama Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	1,259	1,125
Plant Hatch \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	705	628
Plant Vogtle Units 1 and 2 \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	434	382
Plant Vogtle Units 3 and 4 \| Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 24	$ 8

ASSET RETIREMENT OBLIGATIONS _6

ASSET RETIREMENT OBLIGATIONS - Estimated Costs of Decommissioning (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Alabama Power \| Plant Farley
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2037
Decommissioning periods: Completion year	2087
Site study costs	$ 2,048
Alabama Power \| Radiated structures \| Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	1,402
Alabama Power \| Spent fuel management \| Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	513
Alabama Power \| Non-radiated structures \| Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	$ 133
Georgia Power \| Plant Hatch
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2034
Decommissioning periods: Completion year	2075
Site study costs	$ 1,018
Georgia Power \| Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2047
Decommissioning periods: Completion year	2079
Site study costs	$ 883
Georgia Power \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2063
Decommissioning periods: Completion year	2074
Site study costs	$ 347
Georgia Power \| Radiated structures \| Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	771
Georgia Power \| Radiated structures \| Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	628
Georgia Power \| Radiated structures \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Site study costs	284
Georgia Power \| Spent fuel management \| Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	186
Georgia Power \| Spent fuel management \| Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	170
Georgia Power \| Spent fuel management \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Site study costs	30
Georgia Power \| Non-radiated structures \| Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	61
Georgia Power \| Non-radiated structures \| Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	85
Georgia Power \| Non-radiated structures \| Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Site study costs	$ 33

CONSOLIDATED ENTITIES AND EQU_3

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Southern Company (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 1,368	$ 1,443
Southern Holdings Company
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 126	$ 112

CONSOLIDATED ENTITIES AND EQU_4

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SEGCO Equity Method Investments Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) MW	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Percent ownership	14%
Alabama Power \| SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Ownership percentage, equity method investment	50%
Alabama Power \| SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Total megawatt capacity (in MWs) \| MW	1,020
Share of purchased power	$ 112	$ 124	$ 75
Dividends paid by equity method investment	$ 25	14	14
Georgia Power \| SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Ownership percentage, equity method investment	50%
Georgia Power \| SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Share of purchased power	$ 115	$ 127	$ 77
SEGCO \| Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Percent ownership	86%

CONSOLIDATED ENTITIES AND EQU_5

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SPC Noncontrolling Interests and VIEs Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) investor	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Redeemable Noncontrolling Interest [Line Items]
Total assets	$ 139,331	$ 134,891	$ 127,534
Liabilities	104,106	100,359
Equity investments in unconsolidated subsidiaries	1,368	1,443
Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	12,761	13,081
Liabilities	6,063	6,165
Proceeds from sale of equity method investments	50	38
Equity investments in unconsolidated subsidiaries	$ 0	49
Southern Power \| SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Sale of equity interest in limited partnership	33%
Wholly Owned Subsidiary Of Southern Power \| Southern Power \| SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	66%
Wholly Owned Subsidiary Of Southern Power \| Southern Power \| SP Wind
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	100%
SP Solar Holdings I, LP \| Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	67%
SP Solar Holdings I, LP \| Global Atlantic
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	33%
SP Wind \| Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	60%
Number of financial investors \| investor	3
SP Wind \| Financial Investors
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	40%
General Partner \| Wholly Owned Subsidiary Of Southern Power \| Southern Power \| SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest	1%
Variable Interest Entity, Primary Beneficiary \| SP Solar Holdings I, LP \| Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	$ 5,600	5,900
Liabilities	400
Noncontrolling interests related to other partners' interest	1,000	1,100
Variable Interest Entity, Primary Beneficiary \| SP Wind \| Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	2,100	2,200
Liabilities	187	169
Noncontrolling interests related to other partners' interest	38	39
Variable Interest Entity, Primary Beneficiary \| Other Variable Interest Entities \| Southern Power
Redeemable Noncontrolling Interest [Line Items]
Total assets	1,700	$ 1,800
Liabilities	200
Noncontrolling interests related to other partners' interest	$ 800

CONSOLIDATED ENTITIES AND EQU_6

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 1,368	$ 1,443
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	1,235	1,276
SNG \| Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	1,202	1,243
Other \| Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 33	$ 33

CONSOLIDATED ENTITIES AND EQU_7

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Income Statement Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			$ 144	$ 151	$ 76
Impairment charges			0	251	2
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			140	148	50
Impairment charges			0	131	0
Southern Company Gas \| SNG
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			139	146	127
Southern Company Gas \| PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			0	0	(81)
Impairment charges	$ 2	$ 82	84		84
Southern Company Gas \| Other
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			$ 1	$ 2	$ 4

CONSOLIDATED ENTITIES AND EQU_8

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - GAS Equity Method Investments Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2014 mi
Schedule of Equity Method Investments [Line Items]
Impairment charges			$ 0	$ 251	$ 2
Income taxes (benefit)			496	795	267
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Impairment charges			0	131	0
Income taxes (benefit)			211	$ 180	275
Southern Company Gas \| PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Ownership percentage, equity method investment						20%
Pipeline infrastructure (miles) \| mi						118
Impairment charges	$ 2	$ 82	84		84
Impairment charges, after tax	$ 2	$ 58	$ 67		67
Income taxes (benefit)					$ 7

FINANCING - Long-Term Debt (Det

FINANCING - Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Finance lease obligations	$ 298	$ 314
Unamortized fair value adjustment	302	330
Unamortized debt premium (discount), net	(198)	(193)
Unamortized debt issuance expense	(290)	(273)
Total long-term debt	59,686	54,941
Less: Amount due within one year	2,476	4,285
Long-Term Debt	$ 57,210	50,656
Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.16%
Long-term debt, gross	$ 40,235	35,683
Junior subordinated notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.33%
Long-term debt, gross	$ 8,333	8,836
FFB loans
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.88%
Long-term debt, gross	$ 4,788	4,874
Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.77%
Long-term debt, gross	$ 3,400	2,844
First mortgage bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.64%
Long-term debt, gross	$ 2,500	2,275
Medium-term notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	7.03%
Long-term debt, gross	$ 84	84
Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.44%
Long-term debt, gross	$ 234	167
Alabama Power
Debt Instrument [Line Items]
Finance lease obligations	5	5
Unamortized debt premium (discount), net	(20)	(18)
Unamortized debt issuance expense	(73)	(72)
Total long-term debt	11,183	10,630
Less: Amount due within one year	223	301
Long-Term Debt	$ 10,960	10,329
Alabama Power \| Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.95%
Long-term debt, gross	$ 9,875	9,675
Alabama Power \| Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.94%
Long-term debt, gross	$ 1,321	995
Alabama Power \| Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	7.04%
Long-term debt, gross	$ 75	45
Georgia Power
Debt Instrument [Line Items]
Finance lease obligations	240	238
Unamortized debt premium (discount), net	(19)	(18)
Unamortized debt issuance expense	(122)	(117)
Total long-term debt	16,700	14,910
Less: Amount due within one year	502	901
Long-Term Debt	$ 16,198	14,009
Georgia Power \| Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.34%
Long-term debt, gross	$ 9,575	7,925
Georgia Power \| Junior subordinated notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	5%
Long-term debt, gross	$ 270	270
Georgia Power \| FFB loans
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.88%
Long-term debt, gross	$ 4,788	4,874
Georgia Power \| Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.64%
Long-term debt, gross	$ 1,968	1,738
Mississippi Power
Debt Instrument [Line Items]
Finance lease obligations	16	17
Unamortized debt premium (discount), net	1	2
Unamortized debt issuance expense	(9)	(10)
Total long-term debt	1,644	1,545
Less: Amount due within one year	201	1
Long-Term Debt	$ 1,443	1,544
Mississippi Power \| Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.27%
Long-term debt, gross	$ 1,525	1,425
Mississippi Power \| Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.08%
Long-term debt, gross	$ 111	111
Southern Power
Debt Instrument [Line Items]
Finance lease obligations	0	0
Unamortized debt premium (discount), net	(4)	(5)
Unamortized debt issuance expense	(13)	(14)
Total long-term debt	2,711	2,979
Less: Amount due within one year	0	290
Long-Term Debt	2,711	2,689
Fair value gain (loss)	$ (12)	(31)
Southern Power \| Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.05%
Long-term debt, gross	$ 2,728	2,998
Southern Company Gas
Debt Instrument [Line Items]
Finance lease obligations	0	0
Unamortized fair value adjustment	302	330
Unamortized debt premium (discount), net	(8)	(8)
Unamortized debt issuance expense	(34)	(30)
Total long-term debt	7,833	7,442
Less: Amount due within one year	0	400
Long-Term Debt	$ 7,833	7,042
Southern Company Gas \| Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.36%
Long-term debt, gross	$ 4,930	4,769
Southern Company Gas \| First mortgage bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.64%
Long-term debt, gross	$ 2,500	2,275
Southern Company Gas \| Medium-term notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	7.03%
Long-term debt, gross	$ 84	84
Southern Company Gas \| Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.81%
Long-term debt, gross	$ 59	$ 22

FINANCING - Maturities of Long-

FINANCING - Maturities of Long-Term Debt (Details) $ in Millions	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
2024	$ 2,480
2025	4,124
2026	3,791
2027	2,075
2028	2,612
Alabama Power
Debt Instrument [Line Items]
2024	223
2025	251
2026	46
2027	551
2028	107
Alabama Power \| Series 2023A Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
2024	200
Georgia Power
Debt Instrument [Line Items]
2024	503
2025	849
2026	448
2027	512
2028	864
Mississippi Power
Debt Instrument [Line Items]
2024	201
2025	12
2026	66
2027	10
2028	357
Southern Power
Debt Instrument [Line Items]
2024	0
2025	500
2026	964
2027	0
2028	0
Southern Power \| Euro-denominated Debt
Debt Instrument [Line Items]
2028	564
Southern Company Gas
Debt Instrument [Line Items]
2024	0
2025	300
2026	530
2027	154
2028	$ 150

FINANCING - DOE Loan Guarantee

FINANCING - DOE Loan Guarantee Borrowings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 7,566,000,000
Line of credit facility, maximum borrowing capacity	7,605,000,000
Georgia Power
Debt Instrument [Line Items]
Percent of eligible project costs (may not exceed)				70%
Remaining borrowing capacity	1,726,000,000
Principal amortization payments	86,000,000	$ 88,000,000	$ 96,000,000
Line of credit facility, maximum borrowing capacity	$ 1,750,000,000
Basis spread on variable rate	0.375%
Amortization period	5 years
FFB Credit Facility \| Georgia Power
Debt Instrument [Line Items]
Eligible project costs to be reimbursed				$ 5,130,000,000
Funds received under guarantee settlement agreement, less customer refunds				$ 1,492,000,000
Remaining borrowing capacity			$ 0
Principal amortization payments	$ 86,000,000
Line of credit facility, maximum borrowing capacity	$ 4,800,000,000	$ 4,900,000,000
Plant Vogtle Units 3 and 4 \| Georgia Power
Debt Instrument [Line Items]
Ownership interest percentage required for voting for continuing construction	90%

FINANCING - Equity Units (Detai

FINANCING - Equity Units (Details) - USD ($) shares in Millions, $ in Millions		1 Months Ended	12 Months Ended
	Aug. 01, 2022	Aug. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	May 31, 2022
Debt Instrument [Line Items]
Proceeds from issuance of common stock			$ 36	$ 1,808	$ 73
Series 2019A Remarketable Junior Subordinated Notes \| Junior subordinated notes
Debt Instrument [Line Items]
Remarketed principal amount						$ 862.5
Quarterly interest rate						4.475%
Series 2019B Remarketable Junior Subordinated Notes \| Junior subordinated notes
Debt Instrument [Line Items]
Remarketed principal amount						$ 862.5
Quarterly interest rate						5.113%
2019 Series A Equity Units \| Junior subordinated notes
Debt Instrument [Line Items]
Common stock issued to settle purchase contracts (in shares)		25.2
Proceeds from issuance of common stock	$ 1,725

FINANCING - Convertible Senior

FINANCING - Convertible Senior Notes (Details) - Series 2023A Convertible Senior Notes Due 2025 - Convertible Debt $ / shares in Units, $ in Millions		1 Months Ended
	Feb. 28, 2023 USD ($) $ / shares	Feb. 28, 2023 USD ($) d $ / shares	Mar. 31, 2023 USD ($)
Debt Instrument [Line Items]
Debt instrument, face amount \| $	$ 1,500	$ 1,500	$ 225
Quarterly interest rate	3.875%	3.875%
Conversion price (in USD per share) \| $ / shares	$ 84.16	$ 84.16
Redemption price (percentage)	100%
Debt Conversion Terms One
Debt Instrument [Line Items]
Trading days of debt instrument		20
Consecutive trading days		30
Percentage of stock price trigger		130%
Debt Conversion Terms Two
Debt Instrument [Line Items]
Trading days of debt instrument		5
Consecutive trading days		10
Percentage of stock price trigger		98%

FINANCING - Bank Credit Arrange

FINANCING - Bank Credit Arrangements (Details) $ in Millions	Dec. 31, 2023 USD ($)
Line of Credit Facility [Line Items]
2024	$ 280
2025	125
2026	800
2028	6,400
Total	7,605
Unused	7,566
Expires within One Year	280
Southern Company
Line of Credit Facility [Line Items]
2024	150
2025	0
2026	0
2028	1,850
Total	2,000
Unused	1,998
Expires within One Year	150
Alabama Power
Line of Credit Facility [Line Items]
2024	0
2025	0
2026	650
2028	700
Total	1,350
Unused	1,350
Expires within One Year	0
Georgia Power
Line of Credit Facility [Line Items]
2024	0
2025	0
2026	0
2028	1,750
Total	1,750
Unused	1,726
Expires within One Year	0
Mississippi Power
Line of Credit Facility [Line Items]
2024	0
2025	125
2026	150
2028	0
Total	275
Unused	275
Expires within One Year	0
Southern Power
Line of Credit Facility [Line Items]
2024	0
2025	0
2026	0
2028	600
Total	600
Unused	589
Expires within One Year	0
Southern Power \| Continuing Letter of Credit Facility A
Line of Credit Facility [Line Items]
2025	75
2026	100
Unused	8
Southern Power \| Continuing Letter of Credit Facility B
Line of Credit Facility [Line Items]
Unused	7
Southern Company Gas
Line of Credit Facility [Line Items]
2024	100
2025	0
2026	0
2028	1,500
Total	1,600
Unused	1,598
Expires within One Year	100
Other Subsidiaries
Line of Credit Facility [Line Items]
2024	30
2025	0
2026	0
2028	0
Total	30
Unused	30
Expires within One Year	30
Southern Company Gas Capital
Line of Credit Facility [Line Items]
Total	800
Nicor Gas
Line of Credit Facility [Line Items]
2024	100
Total	700
Southern Company and Southern Power
Line of Credit Facility [Line Items]
Line Of Credit Expire Year Five	$ 2,450

FINANCING - Bank Credit Arran_2

FINANCING - Bank Credit Arrangements Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Line of Credit Facility [Line Items]
Ratio of indebtedness to capitalization, debt covenant, required	70%
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	$ 1,700
Other Subsidiaries
Line of Credit Facility [Line Items]
Ratio of indebtedness to capitalization, debt covenant, required	65%
Alabama Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	$ 818
Georgia Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	819
Remarketed pollution control bonds	325
Mississippi Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	69
Southern Power \| Power Purchase Agreement
Line of Credit Facility [Line Items]
Debt instrument, collateral amount	$ 106	$ 106

FINANCING - Notes Payable (Deta

FINANCING - Notes Payable (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Amount Outstanding	$ 2,314	$ 2,609
Weighted Average Interest Rate	5.70%	4.90%
Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 1,794	$ 809
Weighted Average Interest Rate	5.60%	4.70%
Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 520	$ 1,800
Weighted Average Interest Rate	6.40%	5%
Alabama Power
Short-term Debt [Line Items]
Amount Outstanding	$ 40	$ 0
Alabama Power \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 40	$ 0
Weighted Average Interest Rate	5.50%	0%
Georgia Power
Short-term Debt [Line Items]
Amount Outstanding	$ 1,329	$ 1,600
Weighted Average Interest Rate	5.90%	5%
Georgia Power \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 809	$ 0
Weighted Average Interest Rate	5.60%	0%
Georgia Power \| Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 520	$ 1,600
Weighted Average Interest Rate	6.40%	5%
Southern Power
Short-term Debt [Line Items]
Amount Outstanding	$ 138	$ 225
Southern Power \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 138	$ 225
Weighted Average Interest Rate	5.50%	4.70%
Southern Company Gas
Short-term Debt [Line Items]
Amount Outstanding	$ 415	$ 768
Southern Company Gas \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 415	$ 768
Weighted Average Interest Rate	5.50%	4.70%
Southern Company Gas Capital \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 23	$ 285
Weighted Average Interest Rate	5.50%	4.80%
Nicor Gas \| Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 392	$ 283
Weighted Average Interest Rate	5.50%	4.60%
Nicor Gas \| Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 0	$ 200
Weighted Average Interest Rate	0%	4.90%

FINANCING - Outstanding Classes

FINANCING - Outstanding Classes of Capital Stock Narrative (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) shares
Debt Instrument [Line Items]
Stock issued employee and director stock plans (in shares)	2.1
Proceeds from issuance of shares under share-based compensation plans \| $	$ 36
Number of shares reserved for issuance to stock-based compensation plan (in shares)	131
Southern Company Common Stock
Debt Instrument [Line Items]
Remaining shares available for awards (in shares)	26.9

FINANCING - Diluted Earnings Pe

FINANCING - Diluted Earnings Per Share (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
As reported shares (in shares)	1,092	1,075	1,061
Effect of stock-based compensation (in shares)	6	6	7
Diluted shares (in shares)	1,098	1,081	1,068

FINANCING - Preferred Stock Red

FINANCING - Preferred Stock Redemption (Details) - Alabama Power	12 Months Ended
	Dec. 31, 2022 $ / shares shares
4.92% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0492
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	80,000
Redemption Price Per Share (in dollars per share)	$ 103.23
4.72% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0472
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	50,000
Redemption Price Per Share (in dollars per share)	$ 102.18
4.64% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0464
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	60,000
Redemption Price Per Share (in dollars per share)	$ 103.14
4.60% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0460
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	100,000
Redemption Price Per Share (in dollars per share)	$ 104.20
4.52% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0452
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	50,000
Redemption Price Per Share (in dollars per share)	$ 102.93
4.20% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0420
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares outstanding (in shares) \| shares	135,115
Redemption Price Per Share (in dollars per share)	$ 105
5.00% Class A Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0500
Par Value/Stated Capital Per Share (in dollars per share)	$ 25
Shares outstanding (in shares) \| shares	10,000,000
Redemption Price Per Share (in dollars per share)	$ 25

FINANCING - Dividend Restrictio

FINANCING - Dividend Restrictions and Structural Considerations Narrative (Details) $ in Billions	12 Months Ended
	Dec. 31, 2023 USD ($)
Variable Interest Entity [Line Items]
Undistributed retained earnings of subsidiaries	$ 5.5
Southern Company Gas
Variable Interest Entity [Line Items]
Retained earnings, unappropriated	$ 1.7
Southern Company Gas \| Southern Company Gas Capital
Variable Interest Entity [Line Items]
Noncontrolling ownership percentage held by parent	100%

LEASES - Major Categories of Le

LEASES - Major Categories of Lease Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lease obligations	$ 1,788	$ 1,899
Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	98	81
Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	1,115	1,240
Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	25	26
Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	546	542
Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	51	60
Electric generating units(*)
Lessee, Lease, Description [Line Items]
Lease obligations	670	760
Electric generating units(*) \| Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	58	59
Electric generating units(*) \| Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	1,028	1,163
Electric generating units(*) \| Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Electric generating units(*) \| Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Electric generating units(*) \| Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	871	885
Real estate/land \| Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	4	4
Real estate/land \| Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	54	54
Real estate/land \| Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	2	2
Real estate/land \| Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	546	542
Real estate/land \| Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	28	36
Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	123	141
Communication towers \| Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	1	2
Communication towers \| Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	4	4
Communication towers \| Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Communication towers \| Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Communication towers \| Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	23	23
Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	64	34
Railcars \| Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	32	12
Railcars \| Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	27	18
Railcars \| Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	5	3
Railcars \| Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Railcars \| Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Other
Lessee, Lease, Description [Line Items]
Lease obligations	60	79
Other \| Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	3	4
Other \| Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	2	1
Other \| Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	18	21
Other \| Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Other \| Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	$ 0	$ 1

LEASES - Additional Information

LEASES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 1,490	$ 1,585
Transfer of construction work in progress to lease receivables			$ 210
Maximum \| Real estate
Lessee, Lease, Description [Line Items]
Remaining terms	27 years
Maximum \| Land
Lessee, Lease, Description [Line Items]
Lessee, lease term	44 years
Maximum \| Communication towers
Lessee, Lease, Description [Line Items]
Lessee, lease term	17 years
Maximum \| Fuel cells
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	10 years
Alabama Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 93	76
Alabama Power \| Maximum \| Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	16 years
Alabama Power \| Minimum \| Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	1 year
Georgia Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 875	1,002
Variable lease, payment	42	45	41
Georgia Power \| Purchased power, affiliates
Lessee, Lease, Description [Line Items]
Variable lease, payment	21	21	20
Mississippi Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 9	9
Transfer of construction work in progress to lease receivables			39
Sales-type lease, lease receivable			$ 39
Mississippi Power \| Maximum \| Electric generating units
Lessee, Lease, Description [Line Items]
Lessor, sales-type lease, term of contract	15 years
Southern Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 546	542
Lessor, sales-type lease, term of contract			20 years
Sales-type lease, lease receivable			$ 210
Loss on sales-type leases	$ 0	1	$ 40
Southern Power \| Maximum \| Electric generating units
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	23 years
Lessor, sales-type lease, term of contract	18 years
Southern Company Gas
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 51	60
Southern Company Gas \| Maximum
Lessee, Lease, Description [Line Items]
Lessor, remaining term	19 years
Affiliate \| Georgia Power \| Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 416	$ 461
Traditional Electric Operating Companies \| Maximum \| Outdoor lighting
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	10 years

LEASES - Balance Sheet Amounts

LEASES - Balance Sheet Amounts Recorded for Operating and Financing Leases (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Operating Leases
Operating lease ROU assets, net	$ 1,432	$ 1,531
Operating lease obligations - current	183	197
Operating lease obligations - non-current	1,307	1,388
Total operating lease obligations	$ 1,490	$ 1,585
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 272	$ 292
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 11	$ 18
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 287	$ 296
Total finance lease obligations	298	314
Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	566	652
Alabama Power
Operating Leases
Operating lease ROU assets, net	$ 87	$ 71
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 12	$ 9
Operating lease obligations - non-current	81	67
Total operating lease obligations	$ 93	$ 76
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 5	$ 5
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 2	$ 2
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 3	$ 3
Total finance lease obligations	5	5
Alabama Power \| Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	58	59
Georgia Power
Operating Leases
Operating lease ROU assets, net	884	1,007
Operating lease obligations - current	135	151
Operating lease obligations - non-current	740	851
Total operating lease obligations	$ 875	$ 1,002
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 203	$ 205
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 18	$ 16
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 222	$ 222
Total finance lease obligations	240	238
Georgia Power \| Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	$ 813	$ 952
Mississippi Power
Operating Leases
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Operating lease ROU assets, net	$ 9	$ 9
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 3	$ 4
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Operating lease obligations - non-current	$ 6	$ 5
Total operating lease obligations	$ 9	$ 9
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 15	$ 16
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 1	$ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 15	$ 16
Total finance lease obligations	16	17
Southern Power
Operating Leases
Operating lease ROU assets, net	$ 488	$ 489
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 29	$ 28
Operating lease obligations - non-current	517	514
Total operating lease obligations	546	542
Finance Leases
Finance lease ROU assets, net	0	0
Finance lease obligations - current	0	0
Finance lease obligations - non-current	0	0
Total finance lease obligations	0	0
Southern Company Gas
Operating Leases
Operating lease ROU assets, net	$ 47	$ 57
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 11	$ 9
Operating lease obligations - non-current	40	51
Total operating lease obligations	51	60
Finance Leases
Finance lease ROU assets, net	0	0
Finance lease obligations - current	0	0
Finance lease obligations - non-current	0	0
Total finance lease obligations	$ 0	$ 0

LEASES - Lease Costs (Details)

LEASES - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
LEASES - Lease Costs (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease cost
Operating lease cost	$ 252	$ 297	$ 313
Finance lease cost:
Amortization of ROU assets	24	23	21
Interest on lease obligations	14	13	11
Total finance lease cost	38	36	32
Short-term lease costs	40	64	48
Variable lease cost	47	125	96
Sublease income	0	(1)	1
Total lease cost	377	521	490
Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	112	162	165
Alabama Power
Lease cost
Operating lease cost	16	59	58
Finance lease cost:
Amortization of ROU assets	2	1	1
Interest on lease obligations	0	0	0
Total finance lease cost	2	1	1
Short-term lease costs	16	44	15
Variable lease cost	0	13	4
Sublease income	0	0	0
Total lease cost	34	117	78
Alabama Power \| Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	4	48	47
Georgia Power
Lease cost
Operating lease cost	192	198	208
Finance lease cost:
Amortization of ROU assets	19	15	11
Interest on lease obligations	17	17	16
Total finance lease cost	36	32	27
Short-term lease costs	16	13	24
Variable lease cost	74	105	83
Sublease income	0	0	0
Total lease cost	318	348	342
Georgia Power \| Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	174	180	184
Mississippi Power
Lease cost
Operating lease cost	5	5	2
Finance lease cost:
Amortization of ROU assets	1	1	1
Interest on lease obligations	0	1	1
Total finance lease cost	1	2	2
Short-term lease costs	0	0	0
Variable lease cost	0	0	0
Sublease income	0	0	0
Total lease cost	6	7	4
Southern Power
Lease cost
Operating lease cost	34	32	33
Finance lease cost:
Amortization of ROU assets	0	0	0
Interest on lease obligations	0	0	0
Total finance lease cost	0	0	0
Short-term lease costs	0	0	0
Variable lease cost	4	5	5
Sublease income	0	0	0
Total lease cost	38	37	38
Southern Company Gas
Lease cost
Operating lease cost	12	15	19
Finance lease cost:
Amortization of ROU assets	0	0	0
Interest on lease obligations	0	0	0
Total finance lease cost	0	0	0
Short-term lease costs	0	0	0
Variable lease cost	0	0	0
Sublease income	0	0	0
Total lease cost	$ 12	$ 15	$ 19

LEASES - Other Information (Det

LEASES - Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 253	$ 303	$ 308
Operating cash flows from finance leases	15	11	9
Financing cash flows from finance leases	18	16	17
ROU assets obtained under operating leases	100	56	64
Reassessment of ROU assets under operating leases		16
ROU assets obtained under finance leases	$ 3	$ 118	3
Weighted-average remaining lease term in years:
Operating leases	17 years 2 months 12 days	17 years 3 months 18 days
Finance leases	16 years 8 months 12 days	17 years 4 months 24 days
Weighted-average discount rate:
Operating leases	4.68%	4.51%
Finance leases	4.85%	4.87%
Alabama Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 17	$ 58	58
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	2	1	1
ROU assets obtained under operating leases	30	10	3
Reassessment of ROU assets under operating leases		0
ROU assets obtained under finance leases	$ 3	$ 2	0
Weighted-average remaining lease term in years:
Operating leases	11 years 1 month 6 days	13 years
Finance leases	4 years 3 months 18 days	6 years 4 months 24 days
Weighted-average discount rate:
Operating leases	5.02%	4.87%
Finance leases	3.93%	3%
Georgia Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 199	$ 206	211
Operating cash flows from finance leases	22	20	17
Financing cash flows from finance leases	16	10	9
ROU assets obtained under operating leases	26	17	9
Reassessment of ROU assets under operating leases		0
ROU assets obtained under finance leases	$ 18	$ 116	0
Weighted-average remaining lease term in years:
Operating leases	7 years 6 months	8 years 1 month 6 days
Finance leases	10 years 7 months 6 days	11 years 9 months 18 days
Weighted-average discount rate:
Operating leases	4.58%	4.52%
Finance leases	5.95%	8.06%
Mississippi Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 5	$ 5	2
Operating cash flows from finance leases	0	1	1
Financing cash flows from finance leases	1	1	1
ROU assets obtained under operating leases	1	9	0
Reassessment of ROU assets under operating leases		0
ROU assets obtained under finance leases	$ 0	$ 0	0
Weighted-average remaining lease term in years:
Operating leases	4 years 7 months 6 days	4 years 8 months 12 days
Finance leases	11 years 10 months 24 days	12 years 10 months 24 days
Weighted-average discount rate:
Operating leases	3.67%	3.49%
Finance leases	2.74%	2.74%
Southern Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 33	$ 30	28
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	0	0	0
ROU assets obtained under operating leases	7	0	72
Reassessment of ROU assets under operating leases		16
ROU assets obtained under finance leases	$ 0	$ 0	0
Weighted-average remaining lease term in years:
Operating leases	33 years 1 month 6 days	34 years
Weighted-average discount rate:
Operating leases	4.89%	4.86%
Southern Company Gas
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 12	$ 14	19
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	0	0	0
ROU assets obtained under operating leases	7	3	7
Reassessment of ROU assets under operating leases		0
ROU assets obtained under finance leases	$ 0	$ 0	$ 0
Weighted-average remaining lease term in years:
Operating leases	7 years	11 years
Weighted-average discount rate:
Operating leases	3.80%	3.79%

LEASES - Maturities of Lease Li

LEASES - Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Operating leases:
2024	$ 230
2025	203
2026	180
2027	159
2028	143
Thereafter	1,378
Total	2,293
Less: Present value discount	803
Operating lease obligations	1,490	$ 1,585
Finance leases:
2024	22
2025	27
2026	27
2027	27
2028	26
Thereafter	320
Total	449
Less: Present value discount	151
Finance lease obligations	298	314
Alabama Power
Operating leases:
2024	16
2025	14
2026	12
2027	10
2028	7
Thereafter	64
Total	123
Less: Present value discount	30
Operating lease obligations	93	76
Finance leases:
2024	2
2025	1
2026	1
2027	1
2028	1
Thereafter	0
Total	6
Less: Present value discount	1
Finance lease obligations	5	5
Georgia Power
Operating leases:
2024	172
2025	147
2026	142
2027	141
2028	135
Thereafter	303
Total	1,040
Less: Present value discount	165
Operating lease obligations	875	1,002
Finance leases:
2024	27
2025	36
2026	36
2027	36
2028	37
Thereafter	153
Total	325
Less: Present value discount	85
Finance lease obligations	240	238
Mississippi Power
Operating leases:
2024	4
2025	3
2026	2
2027	0
2028	0
Thereafter	1
Total	10
Less: Present value discount	1
Operating lease obligations	9	9
Finance leases:
2024	2
2025	2
2026	2
2027	2
2028	1
Thereafter	10
Total	19
Less: Present value discount	3
Finance lease obligations	16	17
Southern Power
Operating leases:
2024	36
2025	29
2026	29
2027	29
2028	30
Thereafter	1,000
Total	1,153
Less: Present value discount	607
Operating lease obligations	546	542
Finance leases:
2024	0
2025	0
2026	0
2027	0
2028	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	0	0
Southern Company Gas
Operating leases:
2024	12
2025	12
2026	9
2027	4
2028	3
Thereafter	18
Total	58
Less: Present value discount	7
Operating lease obligations	51	60
Finance leases:
2024	0
2025	0
2026	0
2027	0
2028	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	$ 0	$ 0

LEASES - Lease Income (Details)

LEASES - Lease Income (Details) - USD ($) $ in Millions	12 Months Ended
LEASES - Lease Income (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	$ 24	$ 25	$ 15
Lease income - operating leases	164	208	223
Variable lease income	406	417	429
Total lease income	594	$ 650	667
Operating lease, income, comprehensive income, extensible list, not disclosed, flag		Lease income - operating leases
Alabama Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	$ 0	0
Lease income - operating leases	35	77	82
Variable lease income	1	1	0
Total lease income	36	78	82
Georgia Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0	0
Lease income - operating leases	29	32	42
Variable lease income	0	0	0
Total lease income	29	32	42
Mississippi Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	14	15	14
Lease income - operating leases	2	2	2
Variable lease income	0	0	0
Total lease income	16	17	16
Southern Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	10	10	1
Lease income - operating leases	85	85	85
Variable lease income	437	448	456
Total lease income	532	543	542
Southern Company Gas
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0	0
Lease income - operating leases	37	36	35
Variable lease income	0	0	0
Total lease income	$ 37	$ 36	$ 35

LEASES - Undiscounted Cash Flow

LEASES - Undiscounted Cash Flows to be Received Under Tolling Arrangements Accounted for as Sales-type Leases (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2024	$ 38
2025	37
2026	36
2027	35
2028	34
Thereafter	330
Total undiscounted cash flows	510
Lease receivable	311
Difference between undiscounted cash flows and discounted cash flows	199
Other Property and Investments \| Mississippi Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2024	23
2025	22
2026	21
2027	20
2028	19
Thereafter	145
Total undiscounted cash flows	250
Lease receivable	148
Difference between undiscounted cash flows and discounted cash flows	102
Other Current Assets and Net Investment in Sales-type Lease \| Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2024	15
2025	15
2026	15
2027	15
2028	15
Thereafter	185
Total undiscounted cash flows	260
Lease receivable	163
Difference between undiscounted cash flows and discounted cash flows	97
Other current assets \| Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Lease receivable	148	$ 15
Net investment in sales-type leases \| Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Lease receivable	$ 15	$ 154

LEASES - Undiscounted Cash Fl_2

LEASES - Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases (Details) $ in Millions	Dec. 31, 2023 USD ($)
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2024	$ 116
2025	107
2026	108
2027	105
2028	104
Thereafter	706
Total	1,246
Alabama Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2024	7
2025	5
2026	5
2027	4
2028	3
Thereafter	26
Total	50
Southern Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2024	90
2025	75
2026	73
2027	75
2028	76
Thereafter	91
Total	480
Southern Company Gas
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2024	35
2025	29
2026	29
2027	28
2028	28
Thereafter	354
Total	$ 503

LEASES - Leveraged Leases (Narr

LEASES - Leveraged Leases (Narrative) (Details)	12 Months Ended
LEASES - Leveraged Leases (Narrative) (Details)	Dec. 31, 2023 leveragedLease	Dec. 31, 2021 project	Dec. 31, 2020 leveragedLease project
Leveraged Lease [Line Items]
Number of leveraged leases \| leveragedLease	1		4
Number of domestic projects subject to leveraged lease			2
Number of international projects subject to leveraged lease			2
Number of domestic projects subject to leveraged lease sold		1
Remaining lease term	8 years

LEASES - Summary of the Compone

LEASES - Summary of the Components of Income from Leveraged Leases (Details) - Domestic and international leveraged leases $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Leveraged Lease [Line Items]
Pretax leveraged lease income	$ 17
Income tax expense	(5)
Net leveraged lease income	$ 12

INCOME TAXES - Current and Defe

INCOME TAXES - Current and Deferred Income Tax Provisions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Federal —
Current	$ 54	$ 10	$ 50
Deferred	299	455	36
Total federal taxes	353	465	86
State —
Current	41	27	(25)
Deferred	102	303	206
Total state taxes	143	330	181
Income taxes	496	795	267
Alabama Power
Federal —
Current	242	54	104
Deferred	(257)	259	172
Total federal taxes	(15)	313	276
State —
Current	82	14	23
Deferred	14	96	73
Total state taxes	96	110	96
Income taxes	81	423	372
Georgia Power
Federal —
Current	205	38	311
Deferred	195	152	(449)
Total federal taxes	400	190	(138)
State —
Current	37	(21)	71
Deferred	11	201	(101)
Total state taxes	48	180	(30)
Income taxes	448	370	(168)
Mississippi Power
Federal —
Current	49	42	25
Deferred	(26)	(16)	(15)
Total federal taxes	23	26	10
State —
Current	1	0	0
Deferred	12	11	11
Total state taxes	13	11	11
Income taxes	36	37	21
Southern Power
Federal —
Current	(320)	(43)	(340)
Deferred	334	56	343
Total federal taxes	14	13	3
State —
Current	(1)	2	(16)
Deferred	(1)	5	0
Total state taxes	(2)	7	(16)
Income taxes	12	20	(13)
Southern Company Gas
Federal —
Current	62	122	85
Deferred	68	(3)	35
Total federal taxes	130	119	120
State —
Current	24	42	(68)
Deferred	57	19	223
Total state taxes	81	61	155
Income taxes	$ 211	$ 180	$ 275

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	Jul. 31, 2021	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Deferred income tax assets		$ 7,886	$ 7,886	$ 8,398
Income taxes (benefit)			496	795	$ 267
ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		1,387	1,387	1,685
Southern Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		773	$ 773	1,124
Percentage reduction in tax basis of assets			50%
Income taxes (benefit)			$ 12	20	(13)
Southern Power \| ITCs and other credits carryforward
Income Tax Disclosure [Line Items]
Reduction in income tax expense, investment tax credits			332	49	289
Southern Power \| ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		481	481	794
Southern Power \| Production Tax Credit Carryforward
Income Tax Disclosure [Line Items]
Effective income tax rate reconciliation, tax credit, production, amount			26	27	16
Proceeds from transferred tax credit		12
Georgia Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		3,718	3,718	3,844
Income taxes (benefit)			448	370	(168)
State investment tax credit carryforward			452
Georgia Power \| ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		691	691	673
Georgia Power \| Production Tax Credit Carryforward
Income Tax Disclosure [Line Items]
Payments for transferred tax credit			39
Mississippi Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		382	382	399
Income taxes (benefit)			36	37	21
Mississippi Power \| ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		0	0	0
Southern Company Gas
Income Tax Disclosure [Line Items]
Deferred income tax assets		377	377	301
Income taxes (benefit)			211	180	275
Southern Company Gas \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Sequent
Income Tax Disclosure [Line Items]
Deferred tax expense, increase from change in appointment rate	$ 85		85		85
Southern Company Gas \| ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		0	0	0
State and Local Jurisdiction \| Georgia Power
Income Tax Disclosure [Line Items]
Valuation allowance		60	60
State and Local Jurisdiction \| Georgia Power \| ITCs and other credits carryforward
Income Tax Disclosure [Line Items]
Reduction in income tax expense, investment tax credits			49	53	66
Deferred Charges Related To Income Taxes, Current \| Other Noncurrent Assets \| Southern Power \| Unrealized Tax Credits
Income Tax Disclosure [Line Items]
Deferred income tax assets		5	5	$ 17	$ 6
Mississippi \| State and Local Jurisdiction \| Mississippi Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance		32	32
New York \| State and Local Jurisdiction \| Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance		25	25
Oklahoma \| State and Local Jurisdiction \| Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance		11	11
Florida \| State and Local Jurisdiction \| Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance		$ 10	$ 10

INCOME TAXES - Amortization of

INCOME TAXES - Amortization of Deferred Credits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Line Items]
Amortization of investment tax credits	$ 84	$ 83	$ 84
Southern Power
Income Tax Disclosure [Line Items]
Amortization of investment tax credits	$ 58	$ 58	$ 58

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Federal Statutory Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	2.60%	6.20%	5.50%
Employee stock plans' dividend deduction	(0.50%)	(0.50%)	(0.90%)
Non-deductible book depreciation	0.70%	0.60%	0.90%
Flowback of excess deferred income taxes	(9.20%)	(6.60%)	(11.70%)
AFUDC-Equity	(1.10%)	(1.10%)	(1.50%)
Federal PTCs	(1.20%)	0%	0%
ITC amortization	(1.30%)	(1.30%)	(2.20%)
Noncontrolling interests	0.60%	0.50%	0.80%
Leveraged lease impairments and dispositions			(1.40%)
Other	(0.20%)	0%	(0.10%)
Effective income tax (benefit) rate	11.40%	18.80%	10.40%
Alabama Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	5.20%	4.80%	4.60%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.70%	0.50%	0.50%
Flowback of excess deferred income taxes	(19.80%)	(1.90%)	(2.60%)
AFUDC-Equity	(1.20%)	(0.80%)	(0.70%)
Federal PTCs	0%	0%	0%
ITC amortization	(0.10%)	(0.10%)	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions			0%
Other	(0.20%)	0.30%	0.20%
Effective income tax (benefit) rate	5.60%	23.80%	22.90%
Georgia Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	1.50%	6.50%	(5.70%)
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.80%	0.60%	3.10%
Flowback of excess deferred income taxes	(2.60%)	(9.60%)	(49.90%)
AFUDC-Equity	(1.20%)	(1.50%)	(6.40%)
Federal PTCs	(1.40%)	0%	0%
ITC amortization	(0.10%)	(0.10%)	(0.40%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions			0%
Other	(0.30%)	0%	(1.90%)
Effective income tax (benefit) rate	17.70%	16.90%	(40.20%)
Mississippi Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	4.90%	4.40%	4.90%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.40%	0.30%	0.40%
Flowback of excess deferred income taxes	(10.20%)	(7.80%)	(15.20%)
AFUDC-Equity	0%	0%	0%
Federal PTCs	0%	0%	0%
ITC amortization	0%	0%	0%
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions			0%
Other	0.10%	0.30%	0.60%
Effective income tax (benefit) rate	16.20%	18.20%	11.70%
Southern Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	(0.70%)	1.90%	(8.00%)
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0%	0%	0%
Flowback of excess deferred income taxes	0%	0%	0%
AFUDC-Equity	0%	0%	0%
Federal PTCs	(7.40%)	(6.60%)	(4.60%)
ITC amortization	(19.00%)	(17.20%)	(29.70%)
Noncontrolling interests	11.10%	8.40%	13.40%
Leveraged lease impairments and dispositions			0%
Other	0.10%	(0.10%)	(0.40%)
Effective income tax (benefit) rate	5.10%	7.40%	(8.30%)
Southern Company Gas
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	7.80%	6.40%	15.10%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0%	0%	0%
Flowback of excess deferred income taxes	(2.60%)	(2.50%)	(2.80%)
AFUDC-Equity	0%	0%	0%
Federal PTCs	0%	0%	0%
ITC amortization	0%	(0.10%)	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions			0%
Other	(0.60%)	(0.90%)	0.60%
Effective income tax (benefit) rate	25.60%	23.90%	33.80%

INCOME TAXES - Deferred Tax Ass

INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax liabilities —
Deferred income tax liabilities	$ 18,574	$ 18,066
Deferred tax assets —
Deferred income tax assets	7,886	8,398
Valuation allowance	(206)	(257)
Net deferred income tax assets	7,680	8,141
Net deferred income taxes liabilities	10,894	9,925
Accumulated deferred income taxes – assets	(96)	(111)
Accumulated deferred income taxes – liabilities	10,990	10,036
Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	9,683	9,443
Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	2,647	2,350
Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	979	888
Deferred tax assets —
Deferred income tax assets	985	890
AROs
Deferred tax liabilities —
Deferred income tax liabilities	833	876
Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	601	805
AROs
Deferred tax liabilities —
Deferred income tax liabilities	1,902	2,006
Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	797	677
Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	369	400
Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	63	66
Other
Deferred tax liabilities —
Deferred income tax liabilities	700	555
ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	1,387	1,685
Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	857	888
Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	26
Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	363	388
Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	418	365
Other property basis differences
Deferred tax assets —
Deferred income tax assets	197	207
State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	115	136
Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	85	111
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	34	137
Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	79	85
Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	67	72
Other
Deferred tax assets —
Deferred income tax assets	538	552
AROs
Deferred tax assets —
Deferred income tax assets	2,735	2,882
Alabama Power
Deferred tax liabilities —
Deferred income tax liabilities	6,101	6,024
Deferred tax assets —
Deferred income tax assets	1,931	2,043
Valuation allowance	0	0
Net deferred income tax assets	1,931	2,043
Net deferred income taxes liabilities	4,170	3,981
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	4,170	3,981
Alabama Power \| Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	2,566	2,564
Alabama Power \| Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	1,444	1,303
Alabama Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	321	284
Deferred tax assets —
Deferred income tax assets	224	198
Alabama Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	476	499
Alabama Power \| Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	80	185
Alabama Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	667	679
Alabama Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	213	180
Alabama Power \| Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	143	142
Alabama Power \| Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	9	9
Alabama Power \| Other
Deferred tax liabilities —
Deferred income tax liabilities	182	179
Alabama Power \| ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	12	12
Alabama Power \| Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power \| Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	0
Alabama Power \| Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power \| Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	215	175
Alabama Power \| Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power \| State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	115	136
Alabama Power \| Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power \| Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	30	127
Alabama Power \| Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power \| Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	4	4
Alabama Power \| Other
Deferred tax assets —
Deferred income tax assets	188	213
Alabama Power \| AROs
Deferred tax assets —
Deferred income tax assets	1,143	1,178
Georgia Power
Deferred tax liabilities —
Deferred income tax liabilities	7,661	7,426
Deferred tax assets —
Deferred income tax assets	3,718	3,844
Valuation allowance	(75)	(125)
Net deferred income tax assets	3,643	3,719
Net deferred income taxes liabilities	4,018	3,707
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	4,018	3,707
Georgia Power \| Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	3,628	3,447
Georgia Power \| Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	812	693
Georgia Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	446	412
Deferred tax assets —
Deferred income tax assets	316	304
Georgia Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	314	324
Georgia Power \| Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	508	548
Georgia Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	1,196	1,285
Georgia Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	260	226
Georgia Power \| Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	221	253
Georgia Power \| Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	53	57
Georgia Power \| Other
Deferred tax liabilities —
Deferred income tax liabilities	223	181
Georgia Power \| ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	691	673
Georgia Power \| Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	857	888
Georgia Power \| Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	0
Georgia Power \| Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	13	12
Georgia Power \| Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	92	88
Georgia Power \| Other property basis differences
Deferred tax assets —
Deferred income tax assets	83	79
Georgia Power \| State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power \| Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power \| Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power \| Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power \| Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	4	5
Georgia Power \| Other
Deferred tax assets —
Deferred income tax assets	152	186
Georgia Power \| AROs
Deferred tax assets —
Deferred income tax assets	1,510	1,609
Mississippi Power
Deferred tax liabilities —
Deferred income tax liabilities	714	717
Deferred tax assets —
Deferred income tax assets	382	399
Valuation allowance	(41)	(41)
Net deferred income tax assets	341	358
Net deferred income taxes liabilities	373	359
Accumulated deferred income taxes – assets	(96)	(107)
Accumulated deferred income taxes – liabilities	469	466
Mississippi Power \| Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	339	338
Mississippi Power \| Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	188	179
Mississippi Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	49	43
Deferred tax assets —
Deferred income tax assets	52	47
Mississippi Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Mississippi Power \| Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	13	40
Mississippi Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	39	42
Mississippi Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	37	30
Mississippi Power \| Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	5	5
Mississippi Power \| Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	1	0
Mississippi Power \| Other
Deferred tax liabilities —
Deferred income tax liabilities	43	40
Mississippi Power \| ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	0
Mississippi Power \| Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	231	239
Mississippi Power \| Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	3	9
Mississippi Power \| Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power \| Other
Deferred tax assets —
Deferred income tax assets	57	62
Mississippi Power \| AROs
Deferred tax assets —
Deferred income tax assets	39	42
Southern Power
Deferred tax liabilities —
Deferred income tax liabilities	1,360	1,376
Deferred tax assets —
Deferred income tax assets	773	1,124
Valuation allowance	(27)	(27)
Net deferred income tax assets	746	1,097
Net deferred income taxes liabilities	614	279
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	614	279
Southern Power \| Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	1,346	1,351
Southern Power \| Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	12	11
Deferred tax assets —
Deferred income tax assets	10	9
Southern Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power \| Other
Deferred tax liabilities —
Deferred income tax liabilities	2	14
Southern Power \| ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	481	794
Southern Power \| Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power \| Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	0
Southern Power \| Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	49	51
Southern Power \| Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	27	28
Southern Power \| Other property basis differences
Deferred tax assets —
Deferred income tax assets	97	109
Southern Power \| State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power \| Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	85	111
Southern Power \| Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power \| Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power \| Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	6	5
Southern Power \| Other
Deferred tax assets —
Deferred income tax assets	18	17
Southern Power \| AROs
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas
Deferred tax liabilities —
Deferred income tax liabilities	2,041	1,852
Deferred tax assets —
Deferred income tax assets	377	301
Valuation allowance	(7)	(9)
Net deferred income tax assets	370	292
Net deferred income taxes liabilities	1,671	1,560
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	1,671	1,560
Southern Company Gas \| Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	1,576	1,505
Southern Company Gas \| Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	189	150
Southern Company Gas \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	74	68
Deferred tax assets —
Deferred income tax assets	89	89
Southern Company Gas \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas \| Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	0	32
Southern Company Gas \| AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas \| Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	11	15
Southern Company Gas \| Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas \| Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas \| Other
Deferred tax liabilities —
Deferred income tax liabilities	191	82
Southern Company Gas \| ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Estimated loss on regulatory disallowance
Deferred tax assets —
Deferred income tax assets	26
Southern Company Gas \| Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	8	7
Southern Company Gas \| Federal effect of net state deferred tax assets/liabilities
Deferred tax assets —
Deferred income tax assets	101	92
Southern Company Gas \| Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	79	85
Southern Company Gas \| Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas \| Other
Deferred tax assets —
Deferred income tax assets	74	28
Southern Company Gas \| AROs
Deferred tax assets —
Deferred income tax assets	$ 0	$ 0

INCOME TAXES - Federal ITC_PTC

INCOME TAXES - Federal ITC/PTC Carryforwards (Details) - ITC and PTC carryforwards $ in Millions	Dec. 31, 2023 USD ($)
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 829
Alabama Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	12
Georgia Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	131
Southern Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 481

INCOME TAXES - NOL Carryforward

INCOME TAXES - NOL Carryforwards (Details) $ in Millions	Dec. 31, 2023 USD ($)
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	$ 276
Mississippi Power \| Mississippi
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	183
Southern Power
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	38
Southern Power \| Oklahoma
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	26
Southern Power \| Florida
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	10
Southern Power \| Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	2
Other Subsidiaries \| Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	30
Other Subsidiaries \| New York
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	11
Other Subsidiaries \| New York City
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	$ 14

INCOME TAXES - Changes in Unrec

INCOME TAXES - Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Changes in unrecognized tax benefits [Roll Forward]
Beginning balance	$ 80	$ 47	$ 44
Increase from prior periods	88	33	3
Ending balance	116	80	47
Estimated loss on plants under construction
Changes in unrecognized tax benefits [Roll Forward]
Statute of limitations expiration	(52)
Georgia Power
Changes in unrecognized tax benefits [Roll Forward]
Beginning balance	0	0	0
Increase from prior periods	86	0	0
Ending balance	77	0	0
Georgia Power \| Estimated loss on plants under construction
Changes in unrecognized tax benefits [Roll Forward]
Statute of limitations expiration	(9)
Southern Company Gas
Changes in unrecognized tax benefits [Roll Forward]
Beginning balance	32	0	0
Increase from prior periods	2	32	0
Ending balance	34	$ 32	$ 0
Southern Company Gas \| Estimated loss on plants under construction
Changes in unrecognized tax benefits [Roll Forward]
Statute of limitations expiration	$ 0

RETIREMENT BENEFITS - Narrative

RETIREMENT BENEFITS - Narrative (Details) - USD ($)	12 Months Ended
RETIREMENT BENEFITS - Narrative (Details) - USD ($)	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Plan asset amortization period	5 years
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 52,000,000	$ 61,000,000
Expected future employer contributions, next fiscal year	0
Actuarial losses	$ 493,000,000	$ (3,908,000,000)
Change in discount rate	(1800.00%)	2.16%
Pension plans \| Qualified pension plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	73,000,000	$ 73,000,000
Expected future employer contributions, next fiscal year	0
Actuarial losses	$ (33,000,000)	$ (365,000,000)

RETIREMENT BENEFITS - Actuarial

RETIREMENT BENEFITS - Actuarial Assumptions (Details)	12 Months Ended
RETIREMENT BENEFITS - Actuarial Assumptions (Details)	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.09%	2.81%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.13%	2.55%	2.13%
Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.36%	3.34%	3.18%
Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.07%	5.25%
Annual salary increase	4.60%	4.80%
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.18%	2.90%	2.56%
Expected long-term return on plan assets	7.67%	7.21%	7.09%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.08%	2.32%	1.84%
Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.34%	3.26%	3.07%
Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	4.99%	5.18%
Annual salary increase	4.60%	4.80%
Alabama Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.26%	3.12%	2.85%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Alabama Power \| Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.14%	2.58%	2.17%
Alabama Power \| Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.38%	3.36%	3.23%
Alabama Power \| Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.08%	5.26%
Annual salary increase	4.60%	4.80%
Alabama Power \| Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.20%	2.95%	2.63%
Expected long-term return on plan assets	7.95%	7.54%	7.18%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Alabama Power \| Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.09%	2.38%	1.91%
Alabama Power \| Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.35%	3.30%	3.13%
Alabama Power \| Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.01%	5.20%
Annual salary increase	4.60%	4.80%
Georgia Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.07%	2.79%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Georgia Power \| Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.12%	2.51%	2.09%
Georgia Power \| Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.38%	3.37%	3.21%
Georgia Power \| Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.06%	5.25%
Annual salary increase	4.60%	4.80%
Georgia Power \| Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.17%	2.87%	2.52%
Expected long-term return on plan assets	7.49%	6.88%	6.84%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Georgia Power \| Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.07%	2.30%	1.82%
Georgia Power \| Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.34%	3.27%	3.08%
Georgia Power \| Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	4.98%	5.17%
Annual salary increase	4.60%	4.80%
Mississippi Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.07%	2.80%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Mississippi Power \| Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.12%	2.54%	2.12%
Mississippi Power \| Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.37%	3.35%	3.20%
Mississippi Power \| Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.06%	5.25%
Annual salary increase	4.60%	4.80%
Mississippi Power \| Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.17%	2.88%	2.53%
Expected long-term return on plan assets	7.43%	7.22%	6.98%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Mississippi Power \| Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.08%	2.27%	1.78%
Mississippi Power \| Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.33%	3.26%	3.06%
Mississippi Power \| Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	4.98%	5.17%
Annual salary increase	4.60%	4.80%
Southern Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.31%	3.21%	2.99%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Southern Power \| Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.19%	2.79%	2.46%
Southern Power \| Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.37%	3.36%	3.22%
Southern Power \| Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.14%	5.31%
Annual salary increase	4.60%	4.80%
Southern Power \| Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.24%	3.07%	2.78%
Expected long-term return on plan assets	0%	0%	0%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Southern Power \| Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.12%	2.55%	2.12%
Southern Power \| Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.33%	3.25%	3.05%
Southern Power \| Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.06%	5.24%
Annual salary increase	4.60%	4.80%
Southern Company Gas \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.24%	3.04%	2.75%
Expected long-term return on plan assets	8.40%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Southern Company Gas \| Pension plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.12%	2.53%	2.10%
Southern Company Gas \| Pension plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.31%	3.21%	2.97%
Southern Company Gas \| Pension plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.05%	5.24%
Annual salary increase	4.60%	4.80%
Southern Company Gas \| Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.16%	2.82%	2.46%
Expected long-term return on plan assets	6.59%	6.08%	6.54%
Annual salary increase, net periodic costs	4.80%	4.80%	4.80%
Southern Company Gas \| Other postretirement benefit plans \| Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.07%	2.17%	1.64%
Southern Company Gas \| Other postretirement benefit plans \| Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	5.33%	3.22%	3.01%
Southern Company Gas \| Other postretirement benefit plans \| Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	4.98%	5.16%
Annual salary increase	4.60%	4.80%

RETIREMENT BENEFITS - Schedule

RETIREMENT BENEFITS - Schedule of Health Care Cost Trend Rates (Details)	Dec. 31, 2023
Pre-65
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	7%
Ultimate Cost Trend Rate	4.50%
Post-65 medical
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	5.50%
Ultimate Cost Trend Rate	4.50%
Post-65 prescription
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	8.50%
Ultimate Cost Trend Rate	4.50%

RETIREMENT BENEFITS - Accumulat

RETIREMENT BENEFITS - Accumulated Benefit Obligation (Details) - Pension plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	$ 11,991	$ 11,422
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	2,746	2,601
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	3,674	3,534
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	546	520
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	145	135
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	$ 808	$ 801

RETIREMENT BENEFITS - Changes i

RETIREMENT BENEFITS - Changes in Projected Benefit Obligations and Fair Value of Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	$ 12,602,000,000	$ 16,382,000,000
Service cost	275,000,000	412,000,000	$ 434,000,000
Interest cost	626,000,000	408,000,000	346,000,000
Benefits paid	(744,000,000)	(692,000,000)
Actuarial loss	493,000,000	(3,908,000,000)
Balance at end of year	13,252,000,000	12,602,000,000	16,382,000,000
Change in plan assets
Fair value of plan assets at beginning of year	14,218,000,000	17,225,000,000
Actual loss on plan assets	1,092,000,000	(2,376,000,000)
Employer contributions	52,000,000	61,000,000
Benefits paid	(744,000,000)	(692,000,000)
Fair value of plan assets at end of year	14,618,000,000	14,218,000,000	17,225,000,000
Accrued asset	1,366,000,000	1,616,000,000
Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	1,441,000,000	1,849,000,000
Service cost	15,000,000	23,000,000	24,000,000
Interest cost	70,000,000	42,000,000	35,000,000
Benefits paid	(107,000,000)	(109,000,000)
Actuarial loss	(33,000,000)	(365,000,000)
Retiree drug subsidy		1,000,000
Balance at end of year	1,386,000,000	1,441,000,000	1,849,000,000
Change in plan assets
Fair value of plan assets at beginning of year	998,000,000	1,251,000,000
Actual loss on plan assets	131,000,000	(218,000,000)
Employer contributions	73,000,000	73,000,000
Benefits paid	(107,000,000)	(108,000,000)
Fair value of plan assets at end of year	1,095,000,000	998,000,000	1,251,000,000
Accrued asset	(291,000,000)	(443,000,000)
Alabama Power \| Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	2,906,000,000	3,806,000,000
Service cost	64,000,000	99,000,000	102,000,000
Interest cost	145,000,000	96,000,000	82,000,000
Benefits paid	(155,000,000)	(144,000,000)
Actuarial loss	116,000,000	(951,000,000)
Balance at end of year	3,076,000,000	2,906,000,000	3,806,000,000
Change in plan assets
Fair value of plan assets at beginning of year	3,427,000,000	4,141,000,000
Actual loss on plan assets	260,000,000	(579,000,000)
Employer contributions	11,000,000	9,000,000
Benefits paid	(154,000,000)	(144,000,000)
Fair value of plan assets at end of year	3,544,000,000	3,427,000,000	4,141,000,000
Accrued asset	468,000,000	521,000,000
Alabama Power \| Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	344,000,000	440,000,000
Service cost	4,000,000	6,000,000	6,000,000
Interest cost	17,000,000	10,000,000	9,000,000
Benefits paid	(24,000,000)	(23,000,000)
Actuarial loss	(12,000,000)	(89,000,000)
Retiree drug subsidy		0
Balance at end of year	329,000,000	344,000,000	440,000,000
Change in plan assets
Fair value of plan assets at beginning of year	372,000,000	489,000,000
Actual loss on plan assets	52,000,000	(98,000,000)
Employer contributions	3,000,000	4,000,000
Benefits paid	(24,000,000)	(23,000,000)
Fair value of plan assets at end of year	403,000,000	372,000,000	489,000,000
Accrued asset	74,000,000	28,000,000
Georgia Power \| Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	3,851,000,000	5,012,000,000
Service cost	68,000,000	103,000,000	112,000,000
Interest cost	191,000,000	123,000,000	104,000,000
Benefits paid	(224,000,000)	(226,000,000)
Actuarial loss	123,000,000	(1,161,000,000)
Balance at end of year	4,009,000,000	3,851,000,000	5,012,000,000
Change in plan assets
Fair value of plan assets at beginning of year	4,456,000,000	5,415,000,000
Actual loss on plan assets	331,000,000	(753,000,000)
Employer contributions	9,000,000	20,000,000
Benefits paid	(225,000,000)	(226,000,000)
Fair value of plan assets at end of year	4,571,000,000	4,456,000,000	5,415,000,000
Accrued asset	562,000,000	605,000,000
Georgia Power \| Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	514,000,000	656,000,000
Service cost	4,000,000	6,000,000	7,000,000
Interest cost	25,000,000	15,000,000	12,000,000
Benefits paid	(36,000,000)	(38,000,000)
Actuarial loss	(18,000,000)	(125,000,000)
Retiree drug subsidy		0
Balance at end of year	489,000,000	514,000,000	656,000,000
Change in plan assets
Fair value of plan assets at beginning of year	368,000,000	450,000,000
Actual loss on plan assets	51,000,000	(71,000,000)
Employer contributions	27,000,000	27,000,000
Benefits paid	(36,000,000)	(38,000,000)
Fair value of plan assets at end of year	410,000,000	368,000,000	450,000,000
Accrued asset	(79,000,000)	(146,000,000)
Mississippi Power \| Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	569,000,000	743,000,000
Service cost	11,000,000	17,000,000	18,000,000
Interest cost	28,000,000	18,000,000	16,000,000
Benefits paid	(32,000,000)	(30,000,000)
Actuarial loss	23,000,000	(179,000,000)
Balance at end of year	599,000,000	569,000,000	743,000,000
Change in plan assets
Fair value of plan assets at beginning of year	649,000,000	786,000,000
Actual loss on plan assets	50,000,000	(110,000,000)
Employer contributions	2,000,000	3,000,000
Benefits paid	(32,000,000)	(30,000,000)
Fair value of plan assets at end of year	669,000,000	649,000,000	786,000,000
Accrued asset	70,000,000	80,000,000
Mississippi Power \| Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	59,000,000	76,000,000
Service cost	1,000,000	1,000,000	1,000,000
Interest cost	3,000,000	2,000,000	1,000,000
Benefits paid	(4,000,000)	(4,000,000)
Actuarial loss	(2,000,000)	(16,000,000)
Retiree drug subsidy		0
Balance at end of year	57,000,000	59,000,000	76,000,000
Change in plan assets
Fair value of plan assets at beginning of year	24,000,000	29,000,000
Actual loss on plan assets	2,000,000	(4,000,000)
Employer contributions	3,000,000	3,000,000
Benefits paid	(4,000,000)	(4,000,000)
Fair value of plan assets at end of year	25,000,000	24,000,000	29,000,000
Accrued asset	(32,000,000)	(35,000,000)
Southern Power \| Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	163,000,000	222,000,000
Service cost	6,000,000	9,000,000	10,000,000
Interest cost	8,000,000	6,000,000	5,000,000
Benefits paid	(6,000,000)	(5,000,000)
Actuarial loss	6,000,000	(69,000,000)
Balance at end of year	177,000,000	163,000,000	222,000,000
Change in plan assets
Fair value of plan assets at beginning of year	178,000,000	213,000,000
Actual loss on plan assets	12,000,000	(31,000,000)
Employer contributions	2,000,000	1,000,000
Benefits paid	(7,000,000)	(5,000,000)
Fair value of plan assets at end of year	185,000,000	178,000,000	213,000,000
Accrued asset	8,000,000	15,000,000
Southern Power \| Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	9,000,000	11,000,000
Service cost	0	0	0
Interest cost	0	0	0
Benefits paid	(1,000,000)	(1,000,000)
Actuarial loss	1,000,000	(1,000,000)
Retiree drug subsidy		0
Balance at end of year	9,000,000	9,000,000	11,000,000
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual loss on plan assets	0	0
Employer contributions	1,000,000	1,000,000
Benefits paid	(1,000,000)	(1,000,000)
Fair value of plan assets at end of year	0	0	0
Accrued asset	(9,000,000)	(9,000,000)
Southern Company Gas \| Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	868,000,000	1,134,000,000
Service cost	24,000,000	34,000,000	37,000,000
Interest cost	42,000,000	28,000,000	24,000,000
Benefits paid	(104,000,000)	(75,000,000)
Actuarial loss	52,000,000	(253,000,000)
Balance at end of year	882,000,000	868,000,000	1,134,000,000
Change in plan assets
Fair value of plan assets at beginning of year	1,002,000,000	1,241,000,000
Actual loss on plan assets	79,000,000	(167,000,000)
Employer contributions	3,000,000	3,000,000
Benefits paid	(104,000,000)	(75,000,000)
Fair value of plan assets at end of year	980,000,000	1,002,000,000	1,241,000,000
Accrued asset	98,000,000	134,000,000
Southern Company Gas \| Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	179,000,000	237,000,000
Service cost	1,000,000	1,000,000	2,000,000
Interest cost	9,000,000	5,000,000	4,000,000
Benefits paid	(18,000,000)	(18,000,000)
Actuarial loss	1,000,000	(46,000,000)
Retiree drug subsidy		0
Balance at end of year	172,000,000	179,000,000	237,000,000
Change in plan assets
Fair value of plan assets at beginning of year	113,000,000	143,000,000
Actual loss on plan assets	19,000,000	(25,000,000)
Employer contributions	14,000,000	13,000,000
Benefits paid	(18,000,000)	(18,000,000)
Fair value of plan assets at end of year	128,000,000	113,000,000	$ 143,000,000
Accrued asset	(44,000,000)	$ (66,000,000)
Qualified pension plan \| Pension plans
Change in benefit obligation
Balance at end of year	12,540,000,000
Change in plan assets
Employer contributions	0
Qualified pension plan \| Alabama Power \| Pension plans
Change in benefit obligation
Balance at end of year	2,959,000,000
Qualified pension plan \| Georgia Power \| Pension plans
Change in benefit obligation
Balance at end of year	3,865,000,000
Qualified pension plan \| Mississippi Power \| Pension plans
Change in benefit obligation
Balance at end of year	569,000,000
Qualified pension plan \| Southern Power \| Pension plans
Change in benefit obligation
Balance at end of year	154,000,000
Qualified pension plan \| Southern Company Gas \| Pension plans
Change in benefit obligation
Balance at end of year	822,000,000
Non-qualified pension plan \| Pension plans
Change in benefit obligation
Balance at end of year	713,000,000
Non-qualified pension plan \| Alabama Power \| Pension plans
Change in benefit obligation
Balance at end of year	117,000,000
Non-qualified pension plan \| Georgia Power \| Pension plans
Change in benefit obligation
Balance at end of year	145,000,000
Non-qualified pension plan \| Mississippi Power \| Pension plans
Change in benefit obligation
Balance at end of year	29,000,000
Non-qualified pension plan \| Southern Power \| Pension plans
Change in benefit obligation
Balance at end of year	22,000,000
Non-qualified pension plan \| Southern Company Gas \| Pension plans
Change in benefit obligation
Balance at end of year	$ 60,000,000

RETIREMENT BENEFITS - Amounts R

RETIREMENT BENEFITS - Amounts Recognized in Balance Sheets and Amounts in AOCI (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	$ 6,264	$ 5,918
Other current liabilities	(1,029)	(787)
Employee benefit obligations	(1,115)	(1,238)
Other regulatory liabilities, deferred	(715)	(733)
Regulatory asset	66	216
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	2,079	2,290
Other regulatory assets, deferred	2,960	2,455
Other current liabilities	(64)	(56)
Employee benefit obligations	(649)	(618)
Other regulatory liabilities, deferred	(47)	(85)
AOCI	79	24
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	23	34
Other current liabilities	(6)	(6)
Employee benefit obligations	(285)	(437)
Other regulatory liabilities, deferred	(231)	(170)
AOCI	(9)	(4)
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	659	657
Other regulatory assets, deferred	1,858	2,107
Other current liabilities	(191)	(91)
Employee benefit obligations	(155)	(145)
Other regulatory liabilities, deferred	(291)	(315)
Regulatory asset	76	97
Alabama Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	585	629
Other regulatory assets, deferred	821	679
Other current liabilities	(11)	(10)
Employee benefit obligations	(106)	(98)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Alabama Power \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	74	28
Other regulatory assets, deferred	0	0
Other current liabilities	0	0
Employee benefit obligations	0	0
Other regulatory liabilities, deferred	(48)	(21)
AOCI	0	0
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	2,890	2,522
Other current liabilities	(365)	(286)
Employee benefit obligations	(248)	(318)
Regulatory asset		83
Georgia Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	706	738
Other regulatory assets, deferred	1,051	887
Other current liabilities	(13)	(12)
Employee benefit obligations	(131)	(121)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Georgia Power \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	11	19
Other current liabilities	0	0
Employee benefit obligations	(79)	(146)
Other regulatory liabilities, deferred	(85)	(58)
AOCI	0	0
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	285	249
Other current liabilities	(90)	(85)
Employee benefit obligations	(67)	(69)
Other regulatory liabilities, deferred	(92)	(96)
Regulatory asset	44	36
Mississippi Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	99	108
Other regulatory assets, deferred	152	123
Other current liabilities	(2)	(2)
Employee benefit obligations	(27)	(26)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Mississippi Power \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	0
Other current liabilities	0	0
Employee benefit obligations	(32)	(35)
Other regulatory liabilities, deferred	(10)	(9)
AOCI	0	0
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(97)	(83)
Southern Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	31	37
Other regulatory assets, deferred	0	0
Other current liabilities	(2)	(2)
Employee benefit obligations	(21)	(20)
Other regulatory liabilities, deferred	0	0
AOCI	20	11
Southern Power \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	0
Other current liabilities	(1)	(1)
Employee benefit obligations	(8)	(8)
Other regulatory liabilities, deferred	0	0
AOCI	1	0
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	504	497
Other current liabilities	(232)	(254)
Employee benefit obligations	(110)	(120)
Southern Company Gas \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs	158	183
Other regulatory assets, deferred	143	111
Other current liabilities	(3)	(3)
Employee benefit obligations	(58)	(42)
Other regulatory liabilities, deferred	0	0
AOCI	(45)	(75)
Regulatory asset	173	190
Southern Company Gas \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	0
Other current liabilities	0	0
Employee benefit obligations	(44)	(66)
Other regulatory liabilities, deferred	(68)	(58)
AOCI	(10)	(2)
Regulatory asset	$ 24	$ 32

RETIREMENT BENEFITS - Regulator

RETIREMENT BENEFITS - Regulatory Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	$ 6,523	$ 5,833
Regulatory asset	66	216
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	2,720	2,340
Regulatory asset	76	97
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	5,090	4,663
Regulatory asset		83
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	90	4
Regulatory asset	44	36
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	(2,225)	(1,891)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	2,913	2,371
Pension plans \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	821	679
Pension plans \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	1,051	887
Pension plans \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	152	123
Pension plans \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	143	111
Regulatory asset	173	190
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	203	136
Other Postretirement Benefits Plan \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	48	21
Other Postretirement Benefits Plan \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	74	39
Other Postretirement Benefits Plan \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	10	(9)
Other Postretirement Benefits Plan \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	68	58
Regulatory asset	24	32
Prior Service Cost \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	9	10
Prior Service Cost \| Pension plans \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	4	4
Prior Service Cost \| Pension plans \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	6	7
Prior Service Cost \| Pension plans \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	1	1
Prior Service Cost \| Pension plans \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	(7)	(9)
Prior Service Cost \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	13	14
Prior Service Cost \| Other Postretirement Benefits Plan \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	4	4
Prior Service Cost \| Other Postretirement Benefits Plan \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	5	6
Prior Service Cost \| Other Postretirement Benefits Plan \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	1	1
Prior Service Cost \| Other Postretirement Benefits Plan \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	1
Net Actuarial Gain (Loss) \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	2,904	2,361
Net Actuarial Gain (Loss) \| Pension plans \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	817	675
Net Actuarial Gain (Loss) \| Pension plans \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	1,045	880
Net Actuarial Gain (Loss) \| Pension plans \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	151	122
Net Actuarial Gain (Loss) \| Pension plans \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	100	66
Net Actuarial Gain (Loss) \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	216	150
Net Actuarial Gain (Loss) \| Other Postretirement Benefits Plan \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	52	25
Net Actuarial Gain (Loss) \| Other Postretirement Benefits Plan \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	79	45
Net Actuarial Gain (Loss) \| Other Postretirement Benefits Plan \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	11	10
Net Actuarial Gain (Loss) \| Other Postretirement Benefits Plan \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	64	64
Regulatory Amortization \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Pension plans \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Pension plans \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Pension plans \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Pension plans \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	50	54
Regulatory Amortization \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Other Postretirement Benefits Plan \| Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Other Postretirement Benefits Plan \| Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Other Postretirement Benefits Plan \| Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	0	0
Regulatory Amortization \| Other Postretirement Benefits Plan \| Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Net regulatory assets	$ (4)	$ 5

RETIREMENT BENEFITS - Changes_2

RETIREMENT BENEFITS - Changes in Regulatory Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 5,833
Total other comprehensive income (loss)	(10)	$ 71	$ 158
Ending balance	6,523	5,833
Regulatory asset	66	216
Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	(38)
Pension plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2,371
Ending balance	2,913	2,371
Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2,371	2,801
Reclassification adjustments	(7)
Total other comprehensive income (loss)	55	(76)
Ending balance	2,913	2,371	2,801
Pension plans \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(34)	(247)
Total other comprehensive income (loss)	542	(430)
Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	62	(82)
Reclassification adjustments	(8)	6
Pension plans \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	576	(183)
Reclassification adjustments	(33)	(246)
Pension plans \| Change in prior service costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	1
Pension plans \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Pension plans \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	136
Reclassification adjustments	7	(1)
Ending balance	203	136
Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(136)	(74)
Total other comprehensive income (loss)	(5)	(4)
Ending balance	(208)	(136)	(74)
Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	5	2
Total other comprehensive income (loss)	(72)	(62)
Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	(12)	(3)
Other Postretirement Benefits Plan \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	77	64
Reclassification adjustments	6	1
Other Postretirement Benefits Plan \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	1
Other Postretirement Benefits Plan \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2,340
Total other comprehensive income (loss)	2	4	6
Ending balance	2,720	2,340
Regulatory asset	76	97
Alabama Power \| Pension plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	679
Ending balance	821	679
Alabama Power \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	679	809
Ending balance	821	679	809
Alabama Power \| Pension plans \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(11)	(63)
Total other comprehensive income (loss)	142	(130)
Alabama Power \| Pension plans \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	153	(67)
Reclassification adjustments	(10)	(62)
Alabama Power \| Pension plans \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Alabama Power \| Pension plans \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power \| Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	21
Ending balance	48	21
Alabama Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(21)	(62)
Ending balance	(48)	(21)	(62)
Alabama Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	3	0
Total other comprehensive income (loss)	(27)	41
Alabama Power \| Other Postretirement Benefits Plan \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	30	(41)
Reclassification adjustments	3	0
Alabama Power \| Other Postretirement Benefits Plan \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power \| Other Postretirement Benefits Plan \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Georgia Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	4,663
Total other comprehensive income (loss)	3	28	6
Ending balance	5,090	4,663
Regulatory asset		83
Georgia Power \| Pension plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	887
Ending balance	1,051	887
Georgia Power \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	887	971
Ending balance	1,051	887	971
Georgia Power \| Pension plans \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(14)	(75)
Total other comprehensive income (loss)	164	(84)
Georgia Power \| Pension plans \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	178	(9)
Reclassification adjustments	(13)	(74)
Georgia Power \| Pension plans \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Georgia Power \| Pension plans \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Georgia Power \| Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	39
Ending balance	74	39
Georgia Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(39)	(10)
Ending balance	(74)	(39)	(10)
Georgia Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	3	(2)
Total other comprehensive income (loss)	(35)	(29)
Georgia Power \| Other Postretirement Benefits Plan \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	38	27
Reclassification adjustments	4	(2)
Georgia Power \| Other Postretirement Benefits Plan \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	0
Georgia Power \| Other Postretirement Benefits Plan \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	4
Total other comprehensive income (loss)	0	0	1
Ending balance	90	4
Regulatory asset	44	36
Mississippi Power \| Pension plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	123
Ending balance	152	123
Mississippi Power \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	123	146
Ending balance	152	123	146
Mississippi Power \| Pension plans \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(2)	(11)
Total other comprehensive income (loss)	29	(23)
Mississippi Power \| Pension plans \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	31	(12)
Reclassification adjustments	(2)	(11)
Mississippi Power \| Pension plans \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power \| Pension plans \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power \| Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(9)
Ending balance	10	(9)
Mississippi Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(9)	1
Ending balance	(10)	(9)	1
Mississippi Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Total other comprehensive income (loss)	(1)	(10)
Mississippi Power \| Other Postretirement Benefits Plan \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	1	10
Reclassification adjustments	0	0
Mississippi Power \| Other Postretirement Benefits Plan \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power \| Other Postretirement Benefits Plan \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	1	10	40
Southern Power \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	(7)
Southern Power \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0
Total other comprehensive income (loss)	9	(24)
Southern Power \| Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	9	(22)
Reclassification adjustments	0	(2)
Southern Power \| Pension plans \| Change in prior service costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0
Southern Power \| Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	1	(2)
Southern Power \| Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	1	(2)
Southern Company Gas
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(1,891)
Total other comprehensive income (loss)	(15)	7	46
Ending balance	(2,225)	(1,891)
Southern Company Gas \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	(16)
Southern Company Gas \| Pension plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	111
Ending balance	143	111
Regulatory asset	173	190
Southern Company Gas \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	111	91
Reclassification adjustments	1
Total other comprehensive income (loss)	30	(30)
Ending balance	143	111	91
Southern Company Gas \| Pension plans \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(2)	(7)
Total other comprehensive income (loss)	32	20
Southern Company Gas \| Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	29	(30)
Reclassification adjustments	0	0
Southern Company Gas \| Pension plans \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	34	27
Reclassification adjustments	0	1
Southern Company Gas \| Pension plans \| Change in prior service costs
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	1
Southern Company Gas \| Pension plans \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	2	2
Southern Company Gas \| Pension plans \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(4)	(10)
Southern Company Gas \| Other Postretirement Benefits Plan
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	58
Reclassification adjustments	(8)	3
Ending balance	68	58
Regulatory asset	24	32
Southern Company Gas \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(58)	(34)
Total other comprehensive income (loss)	(8)	3
Ending balance	(68)	(58)	$ (34)
Southern Company Gas \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(10)	(11)
Total other comprehensive income (loss)	(10)	(24)
Southern Company Gas \| Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	0	0
Southern Company Gas \| Other Postretirement Benefits Plan \| Net gain \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain (loss)	0	13
Reclassification adjustments	0	0
Southern Company Gas \| Other Postretirement Benefits Plan \| Change in prior service costs \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Company Gas \| Other Postretirement Benefits Plan \| Amortization of regulatory assets \| Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	$ (10)	$ (11)

RETIREMENT BENEFITS - Component

RETIREMENT BENEFITS - Components of Accumulated OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 34,532	$ 32,276	$ 32,234
Total other comprehensive income (loss)	(10)	71	158
Ending balance	35,225	34,532	32,276
Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(18)
Total other comprehensive income (loss)	(38)
Ending balance	(56)	(18)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(1)	(2)
Net loss	80	26
AOCI	79	24
Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	24	100
Reclassification adjustments	(7)
Total other comprehensive income (loss)	55	(76)
Ending balance	79	24	100
Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	62	(82)
Reclassification adjustments	(8)	6
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	1	1
Net loss	(10)	(5)
AOCI	(9)	(4)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	7	(1)
Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(4)	0
Total other comprehensive income (loss)	(5)	(4)
Ending balance	(9)	(4)	0
Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	(12)	(3)
Southern Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	6,916	6,598	6,631
Total other comprehensive income (loss)	1	10	40
Ending balance	6,698	6,916	6,598
Southern Power \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(9)
Total other comprehensive income (loss)	(7)
Ending balance	(16)	(9)
Southern Power \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net loss	20	11
AOCI	20	11
Southern Power \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	11	35
Reclassification adjustments	0
Total other comprehensive income (loss)	9	(24)
Ending balance	20	11	35
Southern Power \| Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	9	(22)
Reclassification adjustments	0	(2)
Southern Power \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net loss	1	0
AOCI	1	0
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Power \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	0	2
Total other comprehensive income (loss)	1	(2)
Ending balance	1	0	2
Southern Power \| Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	1	(2)
Southern Company Gas
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Total other comprehensive income (loss)	(15)	7	46
Southern Company Gas \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	56
Total other comprehensive income (loss)	(16)
Ending balance	40	56
Southern Company Gas \| Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(2)	(3)
Net loss	(43)	(72)
AOCI	(45)	(75)
Southern Company Gas \| Pension plans \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(75)	(45)
Reclassification adjustments	1
Total other comprehensive income (loss)	30	(30)
Ending balance	(45)	(75)	(45)
Southern Company Gas \| Pension plans \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	29	(30)
Reclassification adjustments	0	0
Southern Company Gas \| Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net loss	(10)	(2)
AOCI	(10)	(2)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(8)	3
Southern Company Gas \| Other Postretirement Benefits Plan \| Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(2)	(5)
Total other comprehensive income (loss)	(8)	3
Ending balance	(10)	(2)	$ (5)
Southern Company Gas \| Other Postretirement Benefits Plan \| Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	$ 0	$ 0

RETIREMENT BENEFITS - Compone_2

RETIREMENT BENEFITS - Components of Net Periodic Benefit Cost and Estimated Future Benefit Payments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension plans
Components of net periodic
Service cost	$ 275	$ 412	$ 434
Interest cost	626	408	346
Expected return on plan assets	(1,229)	(1,265)	(1,191)
Recognized net (gain) loss	32	240	314
Net amortization	0	0	1
Prior service cost	0	0	0
Total change	(296)	(205)	(96)
Benefit payments:
2024	748
2025	776
2026	801
2027	822
2028	840
2029 to 2033	4,417
Other Postretirement Benefits Plan
Components of net periodic
Service cost	15	23	24
Interest cost	70	42	35
Expected return on plan assets	(83)	(80)	(76)
Prior service cost	(11)	(1)	2
Total change	(9)	(16)	(15)
Benefit payments:
2024	111
2025	109
2026	108
2027	108
2028	108
2029 to 2033	523
Alabama Power \| Pension plans
Components of net periodic
Service cost	64	99	102
Interest cost	145	96	82
Expected return on plan assets	(297)	(306)	(287)
Recognized net (gain) loss	9	62	82
Net amortization	1	1	1
Prior service cost	0	0	0
Total change	(78)	(48)	(20)
Benefit payments:
2024	164
2025	171
2026	177
2027	182
2028	187
2029 to 2033	988
Alabama Power \| Other Postretirement Benefits Plan
Components of net periodic
Service cost	4	6	6
Interest cost	17	10	9
Expected return on plan assets	(33)	(32)	(30)
Prior service cost	(3)	0	0
Total change	(15)	(16)	(15)
Benefit payments:
2024	24
2025	24
2026	24
2027	24
2028	25
2029 to 2033	123
Georgia Power \| Pension plans
Components of net periodic
Service cost	68	103	112
Interest cost	191	123	104
Expected return on plan assets	(385)	(399)	(375)
Recognized net (gain) loss	13	75	100
Net amortization	1	1	1
Prior service cost	0	0	0
Total change	(112)	(97)	(58)
Benefit payments:
2024	241
2025	248
2026	254
2027	257
2028	260
2029 to 2033	1,337
Georgia Power \| Other Postretirement Benefits Plan
Components of net periodic
Service cost	4	6	7
Interest cost	25	15	12
Expected return on plan assets	(29)	(28)	(26)
Prior service cost	(3)	2	2
Total change	(3)	(5)	(5)
Benefit payments:
2024	40
2025	39
2026	38
2027	38
2028	38
2029 to 2033	188
Mississippi Power \| Pension plans
Components of net periodic
Service cost	11	17	18
Interest cost	28	18	16
Expected return on plan assets	(56)	(57)	(55)
Recognized net (gain) loss	2	11	15
Net amortization	0	0	0
Prior service cost	0	0	0
Total change	(15)	(11)	(6)
Benefit payments:
2024	33
2025	34
2026	36
2027	37
2028	38
2029 to 2033	201
Mississippi Power \| Other Postretirement Benefits Plan
Components of net periodic
Service cost	1	1	1
Interest cost	3	2	1
Expected return on plan assets	(3)	(2)	(1)
Prior service cost	0	0	0
Total change	1	1	1
Benefit payments:
2024	5
2025	5
2026	5
2027	5
2028	4
2029 to 2033	21
Southern Power \| Pension plans
Components of net periodic
Service cost	6	9	10
Interest cost	8	6	5
Expected return on plan assets	(15)	(15)	(14)
Recognized net (gain) loss	0	2	3
Net amortization	0	0	0
Prior service cost	0	0	0
Total change	(1)	2	4
Benefit payments:
2024	7
2025	7
2026	8
2027	8
2028	7
2029 to 2033	47
Southern Power \| Other Postretirement Benefits Plan
Components of net periodic
Service cost	0	0	0
Interest cost	0	0	0
Expected return on plan assets	1	1	1
Prior service cost	0	0	0
Total change	1	1	1
Benefit payments:
2024	1
2025	1
2026	1
2027	1
2028	1
2029 to 2033	1
Southern Company Gas \| Pension plans
Components of net periodic
Service cost	24	34	37
Interest cost	42	28	24
Expected return on plan assets	(85)	(91)	(86)
Recognized net (gain) loss	(5)	8	13
Net amortization	15	15	15
Prior service cost	(3)	(3)	(3)
Total change	(12)	(9)	0
Benefit payments:
2024	57
2025	59
2026	60
2027	62
2028	64
2029 to 2033	336
Southern Company Gas \| Other Postretirement Benefits Plan
Components of net periodic
Service cost	1	1	2
Interest cost	9	5	4
Expected return on plan assets	(10)	(9)	(10)
Prior service cost	6	6	6
Total change	6	$ 3	$ 2
Benefit payments:
2024	17
2025	17
2026	16
2027	16
2028	15
2029 to 2033	$ 64

RETIREMENT BENEFITS - Fair Valu

RETIREMENT BENEFITS - Fair Values of Pension Plan and Other Postretirement Benefit Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets:
Target Allocation	100%	100%
Actual Allocation	100%	100%
Pension plans
Assets:
Plan assets	$ 14,760	$ 14,197
Target Allocation		100%
Actual Allocation		100%
Derivatives		$ (4)
Total		$ 14,193
Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Pension plans \| Domestic equity
Assets:
Plan assets	$ 2,730	$ 2,769
Pension plans \| International equity
Assets:
Plan assets	$ 2,999	$ 3,256
Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 1,973	$ 1,469
Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	44	29
Pension plans \| Corporate bonds
Assets:
Plan assets	1,724	1,494
Pension plans \| Pooled funds
Assets:
Plan assets	777	607
Pension plans \| Cash equivalents and other
Assets:
Plan assets	429	406
Pension plans \| Real estate investments
Assets:
Plan assets	$ 2,053	$ 2,263
Target Allocation	12%	13%
Actual Allocation	14%	15%
Pension plans \| Special situations
Assets:
Plan assets	$ 245	$ 187
Target Allocation	3%	3%
Actual Allocation	2%	2%
Pension plans \| Private equity
Assets:
Plan assets	$ 1,761	$ 1,717
Target Allocation	9%	9%
Actual Allocation	12%	12%
Pension plans \| Private Credit
Assets:
Plan assets	$ 25
Target Allocation	3%
Actual Allocation	0%
Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Other postretirement benefit plans
Assets:
Plan assets	$ 1,096	$ 998
Target Allocation	100%	100%
Actual Allocation	100%	100%
Other postretirement benefit plans \| Equity
Assets:
Target Allocation	60%	61%
Actual Allocation	61%	59%
Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	$ 172	$ 159
Other postretirement benefit plans \| International equity
Assets:
Plan assets	$ 135	$ 137
Other postretirement benefit plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	28%	28%
Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 57	$ 43
Other postretirement benefit plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	47	40
Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	92	79
Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	23	19
Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	456	406
Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	$ 57	$ 62
Target Allocation	4%	5%
Actual Allocation	6%	7%
Other postretirement benefit plans \| Special situations
Assets:
Plan assets	$ 6	$ 6
Target Allocation	1%	1%
Actual Allocation	1%	1%
Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 48	$ 46
Target Allocation	3%	3%
Actual Allocation	4%	5%
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 4,646	$ 5,019
Derivatives		(4)
Total		5,015
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	1,959	2,078
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	1,947	2,166
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	371	399
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	369	376
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans
Assets:
Plan assets	170	173
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	85	85
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	53	58
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	21	19
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	11	11
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	6,399	5,387
Derivatives		0
Total		5,387
Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	771	691
Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	1,052	1,090
Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	1,973	1,469
Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	44	29
Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	1,724	1,494
Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	777	607
Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	58	7
Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans
Assets:
Plan assets	825	722
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	87	74
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	82	79
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	57	43
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	47	40
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	92	79
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	2	0
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	456	406
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Derivatives		0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	3,715	3,791
Derivatives		0
Total		3,791
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	1,684	1,887
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	245	187
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	1,761	1,717
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	25
Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans
Assets:
Plan assets	101	103
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	46	51
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	6	6
Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	48	$ 46
Alabama Power
Assets:
Target Allocation		100%
Actual Allocation		100%
Alabama Power \| Pension plans
Assets:
Plan assets	$ 3,579	$ 3,422
Target Allocation	100%	100%
Actual Allocation	100%	100%
Derivatives		$ (1)
Total		$ 3,421
Alabama Power \| Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Alabama Power \| Pension plans \| Domestic equity
Assets:
Plan assets	$ 663	$ 667
Alabama Power \| Pension plans \| International equity
Assets:
Plan assets	$ 727	$ 785
Alabama Power \| Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Alabama Power \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 479	$ 354
Alabama Power \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	11	7
Alabama Power \| Pension plans \| Corporate bonds
Assets:
Plan assets	418	360
Alabama Power \| Pension plans \| Pooled funds
Assets:
Plan assets	188	146
Alabama Power \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	104	98
Alabama Power \| Pension plans \| Real estate investments
Assets:
Plan assets	$ 497	$ 546
Target Allocation	12%	13%
Actual Allocation	14%	15%
Alabama Power \| Pension plans \| Special situations
Assets:
Plan assets	$ 59	$ 45
Target Allocation	3%	3%
Actual Allocation	2%	2%
Alabama Power \| Pension plans \| Private equity
Assets:
Plan assets	$ 427	$ 414
Target Allocation	9%	9%
Actual Allocation	12%	12%
Alabama Power \| Pension plans \| Private Credit
Assets:
Plan assets	$ 6
Target Allocation	3%
Actual Allocation	0%
Alabama Power \| Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Alabama Power \| Other postretirement benefit plans
Assets:
Plan assets	$ 402	$ 371
Target Allocation	100%	100%
Actual Allocation	100%	100%
Alabama Power \| Other postretirement benefit plans \| Equity
Assets:
Target Allocation	67%	69%
Actual Allocation	66%	65%
Alabama Power \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	$ 22	$ 23
Alabama Power \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	$ 25	$ 27
Alabama Power \| Other postretirement benefit plans \| Fixed income
Assets:
Target Allocation	23%	23%
Actual Allocation	23%	23%
Alabama Power \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 16	$ 12
Alabama Power \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	14	12
Alabama Power \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	8	7
Alabama Power \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	3	3
Alabama Power \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	280	252
Alabama Power \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	$ 17	$ 19
Target Allocation	4%	4%
Actual Allocation	6%	7%
Alabama Power \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	$ 2	$ 2
Target Allocation	1%	1%
Actual Allocation	1%	1%
Alabama Power \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 15	$ 14
Target Allocation	3%	3%
Actual Allocation	4%	4%
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 1,127	$ 1,209
Derivatives		(1)
Total		1,208
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	476	500
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	472	522
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	90	96
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	89	91
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans
Assets:
Plan assets	38	41
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	16	17
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	16	18
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	3	3
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	3	3
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Alabama Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	1,552	1,299
Derivatives		0
Total		1,299
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	187	167
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	255	263
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	479	354
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	11	7
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	418	360
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	188	146
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	14	2
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans
Assets:
Plan assets	333	298
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	6	6
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	9	9
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	16	12
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	14	12
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	8	7
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	280	252
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Alabama Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Derivatives		0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Alabama Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	900	914
Derivatives		0
Total		914
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	408	455
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	59	45
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	427	414
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	6
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans
Assets:
Plan assets	31	32
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	14	16
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	2	2
Alabama Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	15	$ 14
Georgia Power
Assets:
Target Allocation		100%
Actual Allocation		100%
Georgia Power \| Pension plans
Assets:
Plan assets	$ 4,615	$ 4,448
Target Allocation	100%	100%
Actual Allocation	100%	100%
Derivatives		$ (1)
Total		$ 4,447
Georgia Power \| Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Georgia Power \| Pension plans \| Domestic equity
Assets:
Plan assets	$ 852	$ 868
Georgia Power \| Pension plans \| International equity
Assets:
Plan assets	$ 938	$ 1,020
Georgia Power \| Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Georgia Power \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 617	$ 460
Georgia Power \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	14	9
Georgia Power \| Pension plans \| Corporate bonds
Assets:
Plan assets	539	468
Georgia Power \| Pension plans \| Pooled funds
Assets:
Plan assets	243	190
Georgia Power \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	134	127
Georgia Power \| Pension plans \| Real estate investments
Assets:
Plan assets	$ 642	$ 709
Target Allocation	12%	13%
Actual Allocation	14%	15%
Georgia Power \| Pension plans \| Special situations
Assets:
Plan assets	$ 77	$ 59
Target Allocation	3%	3%
Actual Allocation	2%	2%
Georgia Power \| Pension plans \| Private equity
Assets:
Plan assets	$ 551	$ 538
Target Allocation	9%	9%
Actual Allocation	12%	12%
Georgia Power \| Pension plans \| Private Credit
Assets:
Plan assets	$ 8
Target Allocation	3%
Actual Allocation	0%
Georgia Power \| Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Georgia Power \| Other postretirement benefit plans
Assets:
Plan assets	$ 409	$ 368
Target Allocation	100%	100%
Actual Allocation	100%	100%
Georgia Power \| Other postretirement benefit plans \| Equity
Assets:
Target Allocation	58%	58%
Actual Allocation	57%	56%
Georgia Power \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	$ 53	$ 52
Georgia Power \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	$ 56	$ 56
Georgia Power \| Other postretirement benefit plans \| Fixed income
Assets:
Target Allocation	35%	35%
Actual Allocation	35%	34%
Georgia Power \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 16	$ 10
Georgia Power \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	14	12
Georgia Power \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	47	40
Georgia Power \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	13	9
Georgia Power \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	176	154
Georgia Power \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	$ 18	$ 19
Target Allocation	3%	4%
Actual Allocation	4%	5%
Georgia Power \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	$ 2	$ 2
Target Allocation	1%	1%
Actual Allocation	1%	1%
Georgia Power \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 14	$ 14
Target Allocation	2%	2%
Actual Allocation	3%	4%
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 1,451	$ 1,572
Derivatives		(1)
Total		1,571
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	611	651
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	609	678
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	116	125
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	115	118
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans
Assets:
Plan assets	80	76
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	47	46
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	16	17
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	13	9
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	4	4
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Georgia Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	2,001	1,688
Derivatives		0
Total		1,688
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	241	217
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	329	342
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	617	460
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	14	9
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	539	468
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	243	190
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	18	2
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans
Assets:
Plan assets	299	261
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	6	6
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	40	39
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	16	10
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	14	12
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	47	40
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	176	154
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Georgia Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Derivatives		0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Georgia Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	1,163	1,188
Derivatives		0
Total		1,188
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	527	591
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	77	59
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	551	538
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	8
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans
Assets:
Plan assets	30	31
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Trust-owned life insurance
Assets:
Plan assets	0	0
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	14	15
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	2	2
Georgia Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	14	14
Mississippi Power \| Pension plans
Assets:
Plan assets	$ 675	$ 648
Target Allocation	100%	100%
Actual Allocation	100%	100%
Mississippi Power \| Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Mississippi Power \| Pension plans \| Domestic equity
Assets:
Plan assets	$ 124	$ 127
Mississippi Power \| Pension plans \| International equity
Assets:
Plan assets	$ 137	$ 149
Mississippi Power \| Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Mississippi Power \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 90	$ 67
Mississippi Power \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Mississippi Power \| Pension plans \| Corporate bonds
Assets:
Plan assets	79	68
Mississippi Power \| Pension plans \| Pooled funds
Assets:
Plan assets	36	28
Mississippi Power \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	20	18
Mississippi Power \| Pension plans \| Real estate investments
Assets:
Plan assets	$ 94	$ 103
Target Allocation	12%	13%
Actual Allocation	14%	15%
Mississippi Power \| Pension plans \| Special situations
Assets:
Plan assets	$ 11	$ 9
Target Allocation	3%	3%
Actual Allocation	2%	2%
Mississippi Power \| Pension plans \| Private equity
Assets:
Plan assets	$ 81	$ 78
Target Allocation	9%	9%
Actual Allocation	12%	12%
Mississippi Power \| Pension plans \| Private Credit
Assets:
Plan assets	$ 1
Target Allocation	3%
Actual Allocation	0%
Mississippi Power \| Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Mississippi Power \| Other postretirement benefit plans
Assets:
Plan assets	$ 24	$ 24
Target Allocation	100%	100%
Actual Allocation	100%	100%
Mississippi Power \| Other postretirement benefit plans \| Equity
Assets:
Target Allocation	34%	37%
Actual Allocation	33%	35%
Mississippi Power \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	$ 4	$ 4
Mississippi Power \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	$ 4	$ 5
Mississippi Power \| Other postretirement benefit plans \| Fixed income
Assets:
Target Allocation	43%	43%
Actual Allocation	44%	41%
Mississippi Power \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 7	$ 4
Mississippi Power \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	2	2
Mississippi Power \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	1	1
Mississippi Power \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	1	2
Mississippi Power \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	$ 3	$ 4
Target Allocation	10%	11%
Actual Allocation	11%	12%
Mississippi Power \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	$ 0	$ 0
Target Allocation	2%	2%
Actual Allocation	2%	2%
Mississippi Power \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 2	$ 2
Target Allocation	7%	7%
Actual Allocation	10%	10%
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 212	$ 229
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	89	95
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	89	99
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	17	18
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	17	17
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans
Assets:
Plan assets	8	9
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	3	3
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	3	3
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	1	2
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	1	1
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	293	246
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	35	32
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	48	50
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	90	67
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	79	68
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	36	28
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	3	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans
Assets:
Plan assets	12	10
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	1	1
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	1	2
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	7	4
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	2	2
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	1	1
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Mississippi Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	170	173
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	77	86
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	11	9
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	81	78
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	1
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans
Assets:
Plan assets	4	5
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	2	3
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Special situations
Assets:
Plan assets	0	0
Mississippi Power \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	2	2
Southern Power \| Pension plans
Assets:
Plan assets	$ 187	$ 177
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Power \| Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Southern Power \| Pension plans \| Domestic equity
Assets:
Plan assets	$ 34	$ 34
Southern Power \| Pension plans \| International equity
Assets:
Plan assets	$ 38	$ 41
Southern Power \| Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Southern Power \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 25	$ 18
Southern Power \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	1
Southern Power \| Pension plans \| Corporate bonds
Assets:
Plan assets	22	19
Southern Power \| Pension plans \| Pooled funds
Assets:
Plan assets	10	8
Southern Power \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	6	5
Southern Power \| Pension plans \| Real estate investments
Assets:
Plan assets	$ 26	$ 29
Target Allocation	12%	13%
Actual Allocation	14%	15%
Southern Power \| Pension plans \| Special situations
Assets:
Plan assets	$ 3	$ 2
Target Allocation	3%	3%
Actual Allocation	2%	2%
Southern Power \| Pension plans \| Private equity
Assets:
Plan assets	$ 22	$ 21
Target Allocation	9%	9%
Actual Allocation	12%	12%
Southern Power \| Pension plans \| Private Credit
Assets:
Plan assets	$ 0
Target Allocation	3%
Actual Allocation	0%
Southern Power \| Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 59	$ 62
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	24	25
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	25	27
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	5	5
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	5	5
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	82	68
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	10	9
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	13	14
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	25	18
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	1
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	22	19
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	10	8
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	1	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Power \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Power \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	46	47
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	21	24
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	3	2
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	22	21
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Power \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Company Gas \| Pension plans
Assets:
Plan assets	$ 989	$ 1,001
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Company Gas \| Pension plans \| Equity
Assets:
Target Allocation	41%	45%
Actual Allocation	40%	43%
Southern Company Gas \| Pension plans \| Domestic equity
Assets:
Plan assets	$ 182	$ 195
Southern Company Gas \| Pension plans \| International equity
Assets:
Plan assets	$ 201	$ 229
Southern Company Gas \| Pension plans \| Fixed income
Assets:
Target Allocation	30%	30%
Actual Allocation	32%	28%
Southern Company Gas \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 132	$ 104
Southern Company Gas \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	3	2
Southern Company Gas \| Pension plans \| Corporate bonds
Assets:
Plan assets	116	105
Southern Company Gas \| Pension plans \| Pooled funds
Assets:
Plan assets	52	43
Southern Company Gas \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	29	29
Southern Company Gas \| Pension plans \| Real estate investments
Assets:
Plan assets	$ 138	$ 160
Target Allocation	12%	13%
Actual Allocation	14%	15%
Southern Company Gas \| Pension plans \| Special situations
Assets:
Plan assets	$ 16	$ 13
Target Allocation	3%	3%
Actual Allocation	2%	2%
Southern Company Gas \| Pension plans \| Private equity
Assets:
Plan assets	$ 118	$ 121
Target Allocation	9%	9%
Actual Allocation	12%	12%
Southern Company Gas \| Pension plans \| Private Credit
Assets:
Plan assets	$ 2
Target Allocation	3%
Actual Allocation	0%
Southern Company Gas \| Pension plans \| Infrastructure
Assets:
Plan assets	$ 0
Target Allocation	2%
Actual Allocation	0%
Southern Company Gas \| Other postretirement benefit plans
Assets:
Plan assets	$ 127	$ 113
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Company Gas \| Other postretirement benefit plans \| Equity
Assets:
Target Allocation	72%	72%
Actual Allocation	72%	70%
Southern Company Gas \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	$ 69	$ 58
Southern Company Gas \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	$ 24	$ 22
Southern Company Gas \| Other postretirement benefit plans \| Fixed income
Assets:
Target Allocation	26%	26%
Actual Allocation	26%	27%
Southern Company Gas \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 1	$ 1
Southern Company Gas \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	1	1
Southern Company Gas \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	29	27
Southern Company Gas \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	1	1
Southern Company Gas \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	$ 1	$ 2
Target Allocation	1%	1%
Actual Allocation	1%	2%
Southern Company Gas \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 1	$ 1
Target Allocation	1%	1%
Actual Allocation	1%	1%
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans
Assets:
Plan assets	$ 310	$ 353
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Domestic equity
Assets:
Plan assets	130	146
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| International equity
Assets:
Plan assets	130	152
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	25	28
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Real estate investments
Assets:
Plan assets	25	27
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans
Assets:
Plan assets	5	5
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	2	2
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	2	2
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	1	1
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas \| Quoted Prices in Active Markets for Identical Assets (Level 1) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans
Assets:
Plan assets	430	381
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Domestic equity
Assets:
Plan assets	52	49
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| International equity
Assets:
Plan assets	71	77
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	132	104
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	3	2
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Corporate bonds
Assets:
Plan assets	116	105
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Pooled funds
Assets:
Plan assets	52	43
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	4	1
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans
Assets:
Plan assets	120	105
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	67	56
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	22	20
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	1	1
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	1	1
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	29	27
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Other Observable Inputs (Level 2) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Special situations
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private equity
Assets:
Plan assets	0	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Private Credit
Assets:
Plan assets	0
Southern Company Gas \| Significant Unobservable Inputs (Level 3) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans
Assets:
Plan assets	249	267
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| International equity
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Real estate investments
Assets:
Plan assets	113	133
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Special situations
Assets:
Plan assets	16	13
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private equity
Assets:
Plan assets	118	121
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Private Credit
Assets:
Plan assets	2
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Pension plans \| Infrastructure
Assets:
Plan assets	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans
Assets:
Plan assets	2	3
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| International equity
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Real estate investments
Assets:
Plan assets	1	2
Southern Company Gas \| Net Asset Value as a Practical Expedient (NAV) \| Other postretirement benefit plans \| Private equity
Assets:
Plan assets	$ 1	$ 1

RETIREMENT BENEFITS - 401K Plan

RETIREMENT BENEFITS - 401K Plan Matching Contributions (Details) - Employee Savings Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 131	$ 124	$ 119
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	28	26	26
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	31	29	28
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	5	5	5
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	3	3	2
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 18	$ 17	$ 16

STOCK COMPENSATION - Schedule o

STOCK COMPENSATION - Schedule of Employees Participating in Stock-Based Compensation Programs (Details)	Dec. 31, 2023 employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	1,401
Alabama Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	191
Georgia Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	210
Mississippi Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	42
Southern Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	40
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	193

STOCK COMPENSATION - Performanc

STOCK COMPENSATION - Performance Shares Narrative (Details) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Feb. 28, 2024 $ / shares shares	Feb. 28, 2023 $ / shares shares	Dec. 31, 2023 USD ($) type $ / shares shares	Dec. 31, 2022 $ / shares shares	Dec. 31, 2021 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares converted (in shares)		1.8
Shares converted (in dollars per share) \| $ / shares		$ 67.13
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares converted (in shares)	2.3
Shares converted (in dollars per share) \| $ / shares	$ 66.95
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of performance share units issued under performance share plan			3 years	3 years
Minimum percentage of transfer performance shares to common stock based on actual total shareholder return			0%
Maximum percentage of transfer performance shares to common stock based on actual total shareholder return			200%
Number of types of PSUs \| type			2
Performance share units, unvested (in shares)			2.4	2.4
Equity instrument, granted (in shares)			1.3
Equity instruments, vested (in shares)			1.3
Unrecognized compensation cost \| $			$ 32
Total unrecognized compensation cost related to award, weighted average period			19 months
EPS-based and ROE-based Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of performance share units issued under performance share plan			3 years
Equity instrument granted in period, weighted average grant date fair value (in dollars per share) \| $ / shares			$ 68.93	$ 66.87	$ 59.49

STOCK COMPENSATION - Performa_2

STOCK COMPENSATION - Performance Shares, Assumptions Used (Details) - Performance Shares - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	30%	29.60%	30%
Expected term (in years)	3 years	3 years	3 years
Interest rate	3.80%	1.70%	0.20%
Weighted average grant-date fair value (in dollars per share)	$ 76.83	$ 79.69	$ 69.06

STOCK COMPENSATION - Performa_3

STOCK COMPENSATION - Performance Shares, Compensation Costs and Related Tax Benefit (Details) - Performance Shares - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized in income	$ 107	$ 101	$ 112
Tax benefit of compensation cost recognized in income	28	26	29
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized in income	14	12	17
Tax benefit of compensation cost recognized in income	$ 4	$ 4	$ 4

STOCK COMPENSATION - Restricted

STOCK COMPENSATION - Restricted Stock Units Narrative (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instrument granted in period, weighted average grant date fair value (in dollars per share)	$ 68.95	$ 67.20	$ 59.56
Award requisite service period	3 years
Total unrecognized compensation cost related to award, weighted average period	17 months
Restricted stock units, unvested (in shares)	0.9	0.9
Equity instrument, granted (in shares)	0.5
Vested or forfeited (in shares)	0.5
Total compensation cost for award recognized in income	$ 30	$ 26	$ 32
Total compensation cost for award recognized in income, tax benefit	$ 8	$ 7	$ 8
One-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	1 year
Two-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	2 years
Three-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	3 years

STOCK COMPENSATION - Stock Opti

STOCK COMPENSATION - Stock Options Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual term for options outstanding	2 months
Cash received from issuance related to option exercise	$ 28	$ 75	$ 66
Stock Options \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years

STOCK COMPENSATION - Stock Op_2

STOCK COMPENSATION - Stock Option Activity (Details) shares in Millions	12 Months Ended
	Dec. 31, 2023 $ / shares shares
Shares Subject to Option
Beginning balance (in shares) \| shares	1
Exercised (in shares) \| shares	0.7
Ending balance (in shares) \| shares	0.3
Weighted Average Exercise Price
Beginning balance (in dollars per share) \| $ / shares	$ 42.22
Exercised (in dollars per share) \| $ / shares	42.54
Ending balance (in dollars per share) \| $ / shares	$ 41.58

STOCK COMPENSATION - Aggregate

STOCK COMPENSATION - Aggregate Intrinsic Value for Options Exercised (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$ 18	$ 49	$ 34
Tax benefit of options exercised	4	$ 12	$ 7
Georgia Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Mississippi Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Alabama Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Southern Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	$ 0

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets:
Derivative asset	$ 32	$ 141
Liabilities:
Derivative liability	659	617
Collateral already posted, aggregate fair value	62
Recurring
Assets:
Cash equivalents	268	1,447
Other investments	44	35
Total	2,806	3,856
Liabilities:
Contingent consideration	19	12
Other	13
Total	776	753
Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	253	1,427
Other investments	9	9
Total	1,238	2,271
Liabilities:
Contingent consideration	3	0
Other	0
Total	49	32
Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	15	20
Other investments	27	26
Total	1,382	1,424
Liabilities:
Contingent consideration	0	0
Other	13
Total	711	709
Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Other investments	8	0
Total	8	0
Liabilities:
Contingent consideration	16	12
Other	0
Total	16	12
Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Total	178	161
Alabama Power
Assets:
Derivative asset	5	38
Liabilities:
Derivative liability	100	15
Collateral already posted, aggregate fair value	0
Alabama Power \| Recurring
Assets:
Cash equivalents	134	458
Other investments	27	26
Total	1,435	1,671
Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	119	438
Other investments	0	0
Total	715	966
Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	15	20
Other investments	27	26
Total	542	544
Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Other investments	0	0
Total	0	0
Alabama Power \| Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Total	178	161
Georgia Power
Assets:
Derivative asset	2	21
Liabilities:
Derivative liability	113	41
Georgia Power \| Recurring
Assets:
Cash equivalents		355
Total	1,176	1,415
Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents		355
Total	371	640
Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents		0
Total	805	775
Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents		0
Total	0	0
Mississippi Power
Assets:
Derivative asset	1	42
Liabilities:
Derivative liability	47	15
Mississippi Power \| Recurring
Assets:
Cash equivalents	17	47
Total	32	106
Mississippi Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	17	47
Total	17	47
Mississippi Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0	0
Total	15	59
Mississippi Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Total	0	0
Southern Power
Assets:
Derivative asset	3	8
Liabilities:
Derivative liability	27	59
Other		13
Collateral already posted, aggregate fair value	0
Southern Power \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Other		0
Southern Power \| Significant Other Observable Inputs (Level 2)
Liabilities:
Other		13
Southern Power \| Significant Unobservable Inputs (Level 3)
Liabilities:
Other		0
Southern Power \| Recurring
Liabilities:
Contingent consideration	19
Other	13
Total	59	84
Southern Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Contingent consideration	3
Other	0
Total	3	0
Southern Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Contingent consideration	0
Other	13
Total	40	72
Southern Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Contingent consideration	16
Other	0
Total	16	12
Southern Company Gas
Assets:
Derivative asset	21	28
Liabilities:
Derivative liability	87	110
Collateral already posted, aggregate fair value	62	41
Southern Company Gas \| Recurring
Assets:
Cash equivalents		50
Total	26	98
Liabilities:
Total	137	151
Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents		50
Total	9	72
Liabilities:
Total	46	32
Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents		0
Total	17	26
Liabilities:
Total	91	119
Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents		0
Total	0	0
Liabilities:
Total	0	0
Energy-related derivatives \| Recurring
Assets:
Derivative asset	55	199
Liabilities:
Derivative liability	358	210
Energy-related derivatives \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	6	18
Liabilities:
Derivative liability	46	32
Energy-related derivatives \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	49	181
Liabilities:
Derivative liability	312	178
Energy-related derivatives \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Alabama Power \| Recurring
Assets:
Derivative asset	15	62
Liabilities:
Derivative liability	110	39
Energy-related derivatives \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	15	62
Liabilities:
Derivative liability	110	39
Energy-related derivatives \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Georgia Power \| Recurring
Assets:
Derivative asset	13	42
Liabilities:
Derivative liability	124	62
Energy-related derivatives \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	13	42
Liabilities:
Derivative liability	124	62
Energy-related derivatives \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Mississippi Power \| Recurring
Assets:
Derivative asset	15	59
Liabilities:
Derivative liability	61	32
Energy-related derivatives \| Mississippi Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Mississippi Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	15	59
Liabilities:
Derivative liability	61	32
Energy-related derivatives \| Mississippi Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Southern Power \| Recurring
Assets:
Derivative asset	3	8
Liabilities:
Derivative liability	5	12
Energy-related derivatives \| Southern Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Southern Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	3	8
Liabilities:
Derivative liability	5	12
Energy-related derivatives \| Southern Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives \| Southern Company Gas \| Recurring
Assets:
Derivative asset	9	28
Liabilities:
Derivative liability	58	65
Energy-related derivatives \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	6	18
Liabilities:
Derivative liability	46	32
Energy-related derivatives \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	3	10
Liabilities:
Derivative liability	12	33
Energy-related derivatives \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Interest rate derivatives \| Recurring
Assets:
Derivative asset		12
Liabilities:
Derivative liability	264	302
Interest rate derivatives \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset		0
Liabilities:
Derivative liability	0	0
Interest rate derivatives \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset		12
Liabilities:
Derivative liability	264	302
Interest rate derivatives \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset		0
Liabilities:
Derivative liability	0	0
Interest rate derivatives \| Southern Company Gas \| Recurring
Liabilities:
Derivative liability	79	86
Interest rate derivatives \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability	0	0
Interest rate derivatives \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability	79	86
Interest rate derivatives \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability	0	0
Foreign currency derivatives \| Recurring
Liabilities:
Derivative liability	122	216
Foreign currency derivatives \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability	0	0
Foreign currency derivatives \| Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability	122	216
Foreign currency derivatives \| Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability	0	0
Foreign currency derivatives \| Southern Power \| Recurring
Liabilities:
Derivative liability	22	47
Contingent consideration		12
Foreign currency derivatives \| Southern Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability	0	0
Contingent consideration		0
Foreign currency derivatives \| Southern Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability	22	47
Contingent consideration		0
Foreign currency derivatives \| Southern Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability	0	0
Contingent consideration		12
Domestic equity \| Recurring
Assets:
Nuclear decommissioning trusts	980	829
Domestic equity \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	764	651
Domestic equity \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	216	178
Domestic equity \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	651	565
Domestic equity \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	443	396
Domestic equity \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	208	169
Domestic equity \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	322	256
Domestic equity \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	321	255
Domestic equity \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	1	1
Domestic equity \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity \| Southern Company Gas \| Recurring
Assets:
Non-qualified deferred compensation trusts	7	8
Domestic equity \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Domestic equity \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	7	8
Domestic equity \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
Foreign equity \| Recurring
Assets:
Nuclear decommissioning trusts	316	275
Foreign equity \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	145	125
Foreign equity \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	171	150
Foreign equity \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	145	125
Foreign equity \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	145	125
Foreign equity \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	170	149
Foreign equity \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	170	149
Foreign equity \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity \| Southern Company Gas \| Recurring
Assets:
Non-qualified deferred compensation trusts	1	1
Foreign equity \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Foreign equity \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	1	1
Foreign equity \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
U.S. Treasury and government agency securities \| Recurring
Assets:
Nuclear decommissioning trusts	369	285
U.S. Treasury and government agency securities \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	369	285
U.S. Treasury and government agency securities \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	20	19
U.S. Treasury and government agency securities \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	20	19
U.S. Treasury and government agency securities \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	349	266
U.S. Treasury and government agency securities \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	349	266
U.S. Treasury and government agency securities \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Recurring
Assets:
Nuclear decommissioning trusts	48	51
Municipal bonds \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	48	51
Municipal bonds \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	1	1
Municipal bonds \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	1	1
Municipal bonds \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	47	50
Municipal bonds \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	47	50
Municipal bonds \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income \| Recurring
Assets:
Nuclear decommissioning trusts	6	7
Pooled funds – fixed income \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	6	7
Pooled funds – fixed income \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income \| Southern Company Gas \| Recurring
Assets:
Non-qualified deferred compensation trusts	6	7
Pooled funds – fixed income \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Pooled funds – fixed income \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	6	7
Pooled funds – fixed income \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
Corporate bonds \| Recurring
Assets:
Nuclear decommissioning trusts	389	412
Corporate bonds \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	389	412
Corporate bonds \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	231	225
Corporate bonds \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	231	225
Corporate bonds \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	158	187
Corporate bonds \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	158	187
Corporate bonds \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Recurring
Assets:
Nuclear decommissioning trusts	89	90
Mortgage and asset backed securities \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	89	90
Mortgage and asset backed securities \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	25	22
Mortgage and asset backed securities \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	25	22
Mortgage and asset backed securities \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	64	68
Mortgage and asset backed securities \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	64	68
Mortgage and asset backed securities \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Recurring
Assets:
Nuclear decommissioning trusts	169	161
Private equity \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	169	161
Private equity \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	169	161
Private equity \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity \| Alabama Power \| Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	169	161
Cash and cash equivalents \| Recurring
Assets:
Nuclear decommissioning trusts	3	4
Cash and cash equivalents \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	3	4
Cash and cash equivalents \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Cash and cash equivalents \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Cash equivalents \| Southern Company Gas \| Recurring
Assets:
Non-qualified deferred compensation trusts	3	4
Cash equivalents \| Southern Company Gas \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	3	4
Cash equivalents \| Southern Company Gas \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	0	0
Cash equivalents \| Southern Company Gas \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
Other \| Recurring
Assets:
Nuclear decommissioning trusts	70	49
Other \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	58	37
Other \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	3	12
Other \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Other \| Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	9
Other \| Alabama Power \| Recurring
Assets:
Nuclear decommissioning trusts	17	7
Other \| Alabama Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	8	7
Other \| Alabama Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Other \| Alabama Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Other \| Alabama Power \| Recurring \| Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	9
Other \| Georgia Power \| Recurring
Assets:
Nuclear decommissioning trusts	53	42
Other \| Georgia Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	50	30
Other \| Georgia Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	3	12
Other \| Georgia Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	$ 0	0
Other \| Southern Power \| Recurring
Liabilities:
Derivative liability		13
Other \| Southern Power \| Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability		0
Other \| Southern Power \| Recurring \| Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability		13
Other \| Southern Power \| Recurring \| Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability		$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - Alabama Power - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Option, Quantitative Disclosures [Line Items]
Alternative investment	$ 178	$ 161
Unfunded commitments	$ 87	$ 78

FAIR VALUE MEASUREMENTS - Finan

FAIR VALUE MEASUREMENTS - Financial Instruments, Carrying Amount Not Equal to Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 59,400	$ 54,600
Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	55,000	48,600
Alabama Power \| Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	11,200	10,600
Alabama Power \| Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	10,100	9,200
Georgia Power \| Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	16,500	14,700
Georgia Power \| Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	15,100	13,000
Mississippi Power \| Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,600	1,500
Mississippi Power \| Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	1,400	1,300
Southern Power \| Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,700	3,000
Southern Power \| Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	2,600	2,800
Southern Company Gas \| Carrying amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	7,800	7,400
Southern Company Gas \| Fair value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt	$ 6,800	$ 6,500

DERIVATIVES - Energy-Related De

DERIVATIVES - Energy-Related Derivative Contracts (Details) - Energy-related, Natural Gas MMBTU in Millions	Dec. 31, 2023 MMBTU
Derivative [Line Items]
Net Purchased mmBtu	448
Alabama Power
Derivative [Line Items]
Net Purchased mmBtu	118
Georgia Power
Derivative [Line Items]
Net Purchased mmBtu	128
Mississippi Power
Derivative [Line Items]
Net Purchased mmBtu	93
Southern Power
Derivative [Line Items]
Net Purchased mmBtu	7
Southern Company Gas
Derivative [Line Items]
Net Purchased mmBtu	102
Long \| Not Designated as Hedging Instrument \| Southern Company Gas
Derivative [Line Items]
Derivative nonmonetary notional amount net long short position volume	112
Short \| Not Designated as Hedging Instrument \| Southern Company Gas
Derivative [Line Items]
Derivative nonmonetary notional amount net long short position volume	10

DERIVATIVES - Narrative (Detail

DERIVATIVES - Narrative (Details) MMBTU in Millions	12 Months Ended
DERIVATIVES - Narrative (Details) MMBTU in Millions	Dec. 31, 2023 USD ($) MMBTU	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints \| MMBTU	12
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	$ (37,000,000)
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period	19,000,000
Collateral already posted, aggregate fair value	62,000,000
Derivative liability	659,000,000	$ 617,000,000
Interest rate derivatives
Derivative [Line Items]
Derivative liability	52,000,000
Interest rate derivatives \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(12,000,000)	46,000,000	$ 5,000,000
Energy-related derivatives \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (81,000,000)	3,000,000	34,000,000
Alabama Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints \| MMBTU	3
Collateral already posted, aggregate fair value	$ 0
Derivative liability	100,000,000	15,000,000
Alabama Power \| Energy-related derivatives \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ 0
Georgia Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints \| MMBTU	4
Derivative liability	$ 113,000,000	41,000,000
Georgia Power \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (2,000,000)	31,000,000	0
Mississippi Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints \| MMBTU	2
Derivative liability	$ 47,000,000	15,000,000
Southern Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints \| MMBTU	3
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	$ (4,000,000)
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period	11,000,000
Collateral already posted, aggregate fair value	0
Derivative liability	27,000,000	59,000,000
Southern Power \| Interest rate derivatives
Derivative [Line Items]
Derivative liability	0
Southern Power \| Energy-related derivatives \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(18,000,000)	(15,000,000)	12,000,000
Registrants \| Derivative Counterparties
Derivative [Line Items]
Collateral already posted, aggregate fair value	0
Southern Company Gas
Derivative [Line Items]
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	(33,000,000)
Collateral already posted, aggregate fair value	62,000,000	41,000,000
Derivative liability	87,000,000	110,000,000
Southern Company Gas \| Energy-related derivatives \| Cash Flow Hedging
Derivative [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (63,000,000)	$ 18,000,000	$ 22,000,000

DERIVATIVES - Interest Rate Der

DERIVATIVES - Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)
Derivative [Line Items]
Notional Amount	$ 2,200
Fair Value Gain (Loss) December 31, 2023	(264)
Southern Company \| Fair Value Hedges of Existing Debt \| Date one
Derivative [Line Items]
Notional Amount	$ 400
Weighted Average Interest Rate Paid	0.80%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2023	$ (46)
Southern Company \| Fair Value Hedges of Existing Debt \| Date 2
Derivative [Line Items]
Notional Amount	$ 1,000
Weighted Average Interest Rate Paid	2.48%
Interest Rate Received	3.70%
Fair Value Gain (Loss) December 31, 2023	$ (139)
Southern Company Gas \| Fair Value Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 500
Weighted Average Interest Rate Paid	0.49%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2023	$ (79)
Georgia Power \| Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Notional Amount	$ 150
Weighted Average Interest Rate Paid	4.01%
Fair Value Gain (Loss) December 31, 2023	$ 0
Mississippi Power \| Cash Flow Hedges of Forecasted Debt \| Date one
Derivative [Line Items]
Notional Amount	$ 75
Weighted Average Interest Rate Paid	3.84%
Fair Value Gain (Loss) December 31, 2023	$ 0
Mississippi Power \| Cash Flow Hedges of Forecasted Debt \| Date 2
Derivative [Line Items]
Notional Amount	$ 75
Weighted Average Interest Rate Paid	4.04%
Fair Value Gain (Loss) December 31, 2023	$ 0

DERIVATIVES - Foreign Currency

DERIVATIVES - Foreign Currency Derivatives (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2023 EUR (€)	Dec. 31, 2022 USD ($)
Foreign currency derivatives \| Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Pay Notional	$ 2,040
Receive Notional \| €		€ 1,750
Fair Value Gain (Loss) December 31, 2023	(122)
Southern Power
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2023	(12)		$ (31)
Southern Power \| Foreign currency derivatives \| Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Pay Notional	$ 564
Pay Rate	3.78%
Receive Notional \| €		500
Receive Rate	1.85%
Southern Power \| Foreign currency derivatives \| Date \| Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2023	$ (22)
Southern Company \| Foreign currency derivatives \| Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2023	(100)
Southern Company \| Foreign currency derivatives \| Date \| Fair Value Hedges of Existing Debt
Derivative [Line Items]
Pay Notional	$ 1,476
Pay Rate	3.39%
Receive Notional \| €		€ 1,250
Receive Rate	1.88%

DERIVATIVES - Derivative Financ

DERIVATIVES - Derivative Financial Statement Presentation and Amounts With Balance Sheet Offsetting (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	$ 55	$ 211
Derivative asset, gross amount offset	(23)	(70)
Derivative asset, net amounts recognized in the balance sheets	32	141
Derivative liability, gross amounts recognized	744	728
Derivative liability, gross amounts offset	(85)	(111)
Derivative liability, gross amounts recognized in balance sheets	$ 659	$ 617
Derivative asset, statement of financial position, extensible enumeration, not disclosed, flag	Net amounts recognized in the Balance Sheets(b)	Net amounts recognized in the Balance Sheets(b)
Collateral already posted, aggregate fair value	$ 62
Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	9	$ 15
Derivative liability, gross amounts recognized	10	14
Energy-related derivatives \| Other deferred charges and assets \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	2
Energy-related derivatives \| Other deferred credits and liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	2	1
Energy-related derivatives \| Assets from risk management activities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	8	13
Energy-related derivatives \| Other current liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	8	13
Interest rate derivatives
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized in balance sheets	52
Alabama Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amount offset	(10)	(24)
Derivative asset, net amounts recognized in the balance sheets	5	38
Derivative liability, gross amounts offset	(10)	(24)
Derivative liability, gross amounts recognized in balance sheets	100	15
Collateral already posted, aggregate fair value	0
Georgia Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	13	42
Derivative asset, gross amount offset	(11)	(21)
Derivative asset, net amounts recognized in the balance sheets	2	21
Derivative liability, gross amounts recognized	124	62
Derivative liability, gross amounts offset	(11)	(21)
Derivative liability, gross amounts recognized in balance sheets	113	41
Georgia Power \| Energy-related derivatives \| Other deferred charges and assets \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	0
Georgia Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	1
Mississippi Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amount offset	(14)	(17)
Derivative asset, net amounts recognized in the balance sheets	1	42
Derivative liability, gross amounts offset	(14)	(17)
Derivative liability, gross amounts recognized in balance sheets	47	15
Southern Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, net amounts recognized in the balance sheets	3	8
Derivative liability, gross amounts recognized in balance sheets	27	59
Collateral already posted, aggregate fair value	0
Southern Power \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	3
Derivative liability, gross amounts recognized	0	0
Southern Power \| Energy-related derivatives \| Other current liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Southern Power \| Energy-related derivatives \| Other current assets \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	2
Southern Power \| Interest rate derivatives
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized in balance sheets	0
Southern Company Gas
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	9	28
Derivative asset, gross amount offset	12	0
Derivative asset, net amounts recognized in the balance sheets	21	28
Derivative liability, gross amounts recognized	137	151
Derivative liability, gross amounts offset	(50)	(41)
Derivative liability, gross amounts recognized in balance sheets	87	110
Collateral already posted, aggregate fair value	62	41
Southern Company Gas \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	8	12
Derivative liability, gross amounts recognized	10	13
Southern Company Gas \| Energy-related derivatives \| Other deferred charges and assets \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	1
Southern Company Gas \| Energy-related derivatives \| Other deferred credits and liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	2	1
Southern Company Gas \| Energy-related derivatives \| Assets from risk management activities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	7	11
Southern Company Gas \| Energy-related derivatives \| Other current liabilities \| Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	8	12
Hedging Instruments for Regulatory Purposes \| Energy-related derivatives \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	43	175
Derivative liability, gross amounts recognized	315	165
Hedging Instruments for Regulatory Purposes \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	31	52
Hedging Instruments for Regulatory Purposes \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	117	44
Hedging Instruments for Regulatory Purposes \| Energy-related derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	123
Hedging Instruments for Regulatory Purposes \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	198	121
Hedging Instruments for Regulatory Purposes \| Alabama Power \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	15	62
Derivative liability, gross amounts recognized	110	39
Hedging Instruments for Regulatory Purposes \| Alabama Power \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	9	20
Hedging Instruments for Regulatory Purposes \| Alabama Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	41	18
Hedging Instruments for Regulatory Purposes \| Alabama Power \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	69	21
Hedging Instruments for Regulatory Purposes \| Alabama Power \| Energy-related derivatives \| Other current assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	6	42
Hedging Instruments for Regulatory Purposes \| Georgia Power \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	42
Derivative liability, gross amounts recognized	124	61
Hedging Instruments for Regulatory Purposes \| Georgia Power \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	10	6
Hedging Instruments for Regulatory Purposes \| Georgia Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	42	18
Hedging Instruments for Regulatory Purposes \| Georgia Power \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	82	43
Hedging Instruments for Regulatory Purposes \| Georgia Power \| Energy-related derivatives \| Other current assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	2	36
Hedging Instruments for Regulatory Purposes \| Mississippi Power \| Energy-related derivatives \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	15	59
Derivative liability, gross amounts recognized	61	32
Hedging Instruments for Regulatory Purposes \| Mississippi Power \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	26
Hedging Instruments for Regulatory Purposes \| Mississippi Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	34	8
Hedging Instruments for Regulatory Purposes \| Mississippi Power \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	27	24
Hedging Instruments for Regulatory Purposes \| Mississippi Power \| Energy-related derivatives \| Other current assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	33
Hedging Instruments for Regulatory Purposes \| Southern Power \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	1
Hedging Instruments for Regulatory Purposes \| Southern Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Hedging Instruments for Regulatory Purposes \| Southern Company Gas \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	1
Hedging Instruments for Regulatory Purposes \| Southern Company Gas \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	4	4
Hedging Instruments for Regulatory Purposes \| Southern Company Gas \| Energy-related derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	12
Hedging Instruments for Regulatory Purposes \| Southern Company Gas \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	20	33
Cash Flow and Fair Value Hedging \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	21
Derivative liability, gross amounts recognized	419	549
Cash Flow and Fair Value Hedging \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	6
Cash Flow and Fair Value Hedging \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	4	4
Cash Flow and Fair Value Hedging \| Energy-related derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	3
Cash Flow and Fair Value Hedging \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	29	27
Cash Flow and Fair Value Hedging \| Interest rate derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Interest rate derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	190	240
Cash Flow and Fair Value Hedging \| Interest rate derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	12
Cash Flow and Fair Value Hedging \| Interest rate derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	74	62
Cash Flow and Fair Value Hedging \| Foreign currency derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Foreign currency derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	88	182
Cash Flow and Fair Value Hedging \| Foreign currency derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Foreign currency derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	34	34
Cash Flow and Fair Value Hedging \| Southern Power \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	5
Derivative liability, gross amounts recognized	27	59
Cash Flow and Fair Value Hedging \| Southern Power \| Energy-related derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	5
Cash Flow and Fair Value Hedging \| Southern Power \| Energy-related derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Power \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	5	12
Cash Flow and Fair Value Hedging \| Southern Power \| Energy-related derivatives \| Other current assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Power \| Foreign currency derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Power \| Foreign currency derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	11	36
Cash Flow and Fair Value Hedging \| Southern Power \| Foreign currency derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	11	11
Cash Flow and Fair Value Hedging \| Southern Power \| Foreign currency derivatives \| Other current assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Energy-related derivatives \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	4
Derivative liability, gross amounts recognized	107	105
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Energy-related derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	3
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Energy-related derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	24	15
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Interest rate derivatives \| Other deferred charges and assets \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Interest rate derivatives \| Other deferred credits and liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	59	72
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Interest rate derivatives \| Assets from risk management activities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging \| Southern Company Gas \| Interest rate derivatives \| Other current liabilities \| Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	$ 20	$ 14

DERIVATIVES - Schedule of Unrea

DERIVATIVES - Schedule of Unrealized Gain (Loss) Recognized in the Balance Sheet (Details) - Energy-related derivatives - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	$ (257)	$ 9
Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(180)	(71)
Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(87)	(23)
Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	9	72
Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	1	31
Alabama Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(95)	23
Alabama Power \| Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(67)	(8)
Alabama Power \| Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(32)	(7)
Alabama Power \| Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	4	29
Alabama Power \| Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	0	9
Georgia Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(112)	(19)
Georgia Power \| Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(80)	(26)
Georgia Power \| Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(33)	(14)
Georgia Power \| Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	0	19
Georgia Power \| Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	1	2
Mississippi Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(46)	27
Mississippi Power \| Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(25)	(13)
Mississippi Power \| Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(22)	(2)
Mississippi Power \| Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	1	22
Mississippi Power \| Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	0	20
Southern Company Gas
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(4)	(22)
Southern Company Gas \| Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(8)	(24)
Southern Company Gas \| Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	0	0
Southern Company Gas \| Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	4	2
Southern Company Gas \| Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	$ 0	$ 0

DERIVATIVES - Pre-Tax Effects o

DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (58)	$ (80)	$ (67)
Energy-related derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(81)	3	34
Interest rate derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(12)	46	5
Foreign currency derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	14	(105)	(103)
Foreign currency derivatives \| Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	21	(24)	(3)
Georgia Power \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(2)	31	0
Southern Power
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(4)	(120)	(91)
Southern Power \| Energy-related derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(18)	(15)	12
Southern Power \| Foreign currency derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	14	(105)	(103)
Southern Company Gas \| Energy-related derivatives \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (63)	$ 18	$ 22

DERIVATIVES - Pre-Tax Effects_2

DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Total other operations and maintenance	$ 6,093	$ 6,573	$ 5,902
Depreciation and amortization	4,525	3,663	3,565
Interest expense, net of amounts capitalized	(2,446)	(2,022)	(1,837)
Other income (expense), net	553	500	449
Natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Cost of sales	1,644	3,004	1,619
Energy-related derivatives \| Cost of Sales \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(44)	37	17
Energy-related derivatives \| Operating Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	(2)	0	0
Energy-related derivatives \| Depreciation and Amortization \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(23)	(5)	9
Interest rate derivatives \| Interest Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(35)	(25)	(27)
Interest rate derivatives \| Interest Expense \| Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	37	(291)	(30)
Foreign currency derivatives \| Interest Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(11)	(19)	(24)
Foreign currency derivatives \| Other Income (Expense) \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	19	(83)	(104)
Gain (loss) on foreign currency fair value hedges	69	(106)	(63)
Amount excluded from effectiveness testing recognized in earnings	(21)	24	3
Southern Power
Derivative Instruments, Gain (Loss) [Line Items]
Total other operations and maintenance	473	482	423
Depreciation and amortization	504	516	517
Interest expense, net of amounts capitalized	(129)	(138)	(147)
Other income (expense), net	12	7	10
Southern Power \| Energy-related derivatives \| Depreciation and Amortization \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(23)	(5)	9
Southern Power \| Foreign currency derivatives \| Interest Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(11)	(19)	(24)
Southern Power \| Foreign currency derivatives \| Other Income (Expense) \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	19	(83)	(104)
Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Cost of sales	1,644	3,004	1,619
Total other operations and maintenance	1,194	1,176	1,072
Depreciation and amortization	582	559	536
Interest expense, net of amounts capitalized	(310)	(263)	(238)
Other income (expense), net	57	53	(53)
Southern Company Gas \| Energy-related derivatives \| Operating Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	(2)	0	0
Southern Company Gas \| Interest rate derivatives \| Interest Expense \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	(19)	(4)	0
Southern Company Gas \| Interest rate derivatives \| Interest Expense \| Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	6	(86)	0
Southern Company Gas \| Foreign currency derivatives \| Other Income (Expense) \| Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	$ (44)	$ 37	$ 17

DERIVATIVES - Cumulative Basis

DERIVATIVES - Cumulative Basis Adjustments for Fair Value Hedges (Details) - Long-term debt - Fair Value Hedging - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Carrying Amount of the Hedged Item	$ (3,024)	$ (2,927)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	235	282
Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Carrying Amount of the Hedged Item	(427)	(415)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	$ 70	$ 81

DERIVATIVES - Pre-Tax Effects_3

DERIVATIVES - Pre-Tax Effects of Derivatives Not Designated as Hedging (Details) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Energy-related derivatives \| Natural gas revenues
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 0	$ (11,000,000)	$ (117,000,000)
Energy-related derivatives \| Cost of natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	59,000,000	(65,000,000)	(27,000,000)
Energy-related derivatives \| Cost of natural gas \| Not Designated as Hedging Instrument \| Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	59,000,000	(76,000,000)	(144,000,000)
Weather derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 15,000,000	$ (7,000,000)	$ 0

ACQUISITIONS AND DISPOSITIONS -

ACQUISITIONS AND DISPOSITIONS - Southern Company Narrative (Details)	1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2021 USD ($) project	Oct. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023 project
Business Acquisition [Line Items]
Proceeds from sale of assets subject to leveraged lease	$ 673,000,000	$ 45,000,000
Gain (loss) on sale of assets subject to leveraged lease		0
Leveraged leases, income tax benefits		$ 16,000,000
Number of international projects subject to leveraged lease terminated \| project	2			2
Gain (loss) on termination of leveraged leases	$ 93,000,000
Gain (loss) on termination of leveraged leases, after tax	$ 99,000,000
All Other
Business Acquisition [Line Items]
Lease, impairment loss			$ 7,000,000
Lease, impairment loss, after tax			$ 6,000,000

ACQUISITIONS AND DISPOSITIONS_2

ACQUISITIONS AND DISPOSITIONS - Alabama Power Narrative (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Business Acquisition [Line Items]
Capital expenditures related to qualifying projects		$ 9,095	$ 7,923	$ 7,586
Alabama Power
Business Acquisition [Line Items]
Capital expenditures related to qualifying projects		$ 2,022	$ 2,016	$ 1,753
Alabama Power \| Calhoun Generating Station
Business Acquisition [Line Items]
Purchase price	$ 179
Capital expenditures related to qualifying projects	$ 171

ACQUISITIONS AND DISPOSITIONS_3

ACQUISITIONS AND DISPOSITIONS - Schedule of Asset Acquisitions (Details) - Southern Power $ in Millions	2 Months Ended	12 Months Ended
	Feb. 14, 2024 MW	Dec. 31, 2023 USD ($) MW	Dec. 31, 2021 MW
Deuel Harvest
Asset Acquisition [Line Items]
Approximate Nameplate Capacity (MW)			300
Deuel Harvest \| Maximum
Asset Acquisition [Line Items]
PPA Contract Period			25 years
Deuel Harvest \| Minimum
Asset Acquisition [Line Items]
PPA Contract Period			15 years
Deuel Harvest \| Deuel Harvest
Asset Acquisition [Line Items]
Ownership Percentage			100%
Millers Branch
Asset Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		200
Ownership Percentage		10,000%
PPA Contract Period		20 years
Millers Branch \| Maximum
Asset Acquisition [Line Items]
Addition to nameplate capacity		300
Millers Branch \| Maximum \| Subsequent Event
Asset Acquisition [Line Items]
Addition to nameplate capacity	205
South Cheyenne
Asset Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		150
Ownership Percentage		10,000%
PPA Contract Period		20 years
South Cheyenne Solar Facility and Millers Branch Solar Development
Asset Acquisition [Line Items]
Payments to acquire businesses \| $		$ 193

ACQUISITIONS AND DISPOSITIONS_4

ACQUISITIONS AND DISPOSITIONS - Southern Power Narrative (Details) - SOUTHERN POWER CO - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Asset Acquisition [Line Items]
Gain on dispositions, net	$ 20	$ 2	$ 41
South Cheyenne Solar Facility and Millers Branch Solar Development
Asset Acquisition [Line Items]
Payments to acquire businesses	193
Wind Generating Facility
Asset Acquisition [Line Items]
Gain on dispositions, net	$ 37		$ 37

ACQUISITIONS AND DISPOSITIONS_5

ACQUISITIONS AND DISPOSITIONS - Schedule of Construction Projects (Details) - Southern Power - MW	1 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2022	Dec. 31, 2021
Garland Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		88	88
PPA Contract Period		20 years
Nameplate capacity placed in service (in MWs)		15	73
Tranquility Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		72	72
PPA Contract Period		20 years
Nameplate capacity placed in service (in MWs)			32
Glass Sands
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)			118
PPA Contract Period			12 years
Tranquillity Solar Storage
Business Acquisition [Line Items]
Nameplate capacity placed in service (in MWs)		40
Tranquility Solar Storage \| Class B Membership Interest \| Tranquility Solar Storage
Business Acquisition [Line Items]
Noncontrolling ownership percentage sold by parent	100%
Garland Solar Storage \| Class B Membership Interest \| Garland Solar Storage
Business Acquisition [Line Items]
Noncontrolling ownership percentage sold by parent	100%
Glass Sands \| Glass Sands
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent	100%

ACQUISITIONS AND DISPOSITIONS_6

ACQUISITIONS AND DISPOSITIONS - GAS Acquisitions and Dispositions Narrative (Details) - Southern Company Gas $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Jul. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2022 USD ($) storageFacility
Business Acquisition [Line Items]
Gain (loss) on dispositions			$ 7	$ 4	$ 127
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Sequent
Business Acquisition [Line Items]
Consideration for sale	$ 159
Gain (loss) on dispositions	121		121		121
Gain (loss) on dispositions, after tax	92		92		92
Deferred tax expense, increase from change in appointment rate	$ 85		$ 85		$ 85
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Natural Gas Storage Facilities
Business Acquisition [Line Items]
Consideration for sale						$ 186
Gain (loss) on dispositions		$ (131)
Gain (loss) on dispositions, after tax		$ (99)
Number of natural gas storage facilities sold \| storageFacility						2

SEGMENT AND RELATED INFORMATI_3

SEGMENT AND RELATED INFORMATION - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) segment state	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Total operating revenues	24,828	25,941	23,463
Southern Power
Segment Reporting Information [Line Items]
Total operating revenues	2,189	3,369	2,216
Total operating revenues	1,630	2,805	1,605
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues	4,702	5,962	4,380
Total operating revenues	$ 4,598	5,905	6,293
Number of reportable segments \| segment	3
Number of states in which entity operates \| state	4
Southern Company Gas \| Southern Power
Segment Reporting Information [Line Items]
Total operating revenues			18
Southern Natural Gas Company, LLC \| Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50%
Dalton Pipeline \| Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50%
Wholesale revenues, affiliates \| Southern Power \| Traditional Electric Operating Companies
Segment Reporting Information [Line Items]
Total operating revenues	$ 537	$ 875	$ 515

SEGMENT AND RELATED INFORMATI_4

SEGMENT AND RELATED INFORMATION - Financial Data for Business Segments (Details) $ in Millions	1 Months Ended		3 Months Ended					12 Months Ended
	Dec. 31, 2021 USD ($) project	Jul. 31, 2021 USD ($)	Dec. 31, 2023 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2023 USD ($) project	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Segment Reporting Information [Line Items]
Total operating revenues								$ 25,253	$ 29,279	$ 23,113
Depreciation and amortization								4,525	3,663	3,565
Interest income								85	59	22
Earnings from equity method investments								144	151	76
Interest expense								2,446	2,022	1,837
Income taxes (benefit)								496	795	267
Segment net income (loss)								3,976	3,524	2,393
Goodwill	$ 5,280		$ 5,161		$ 5,161			5,161	5,161	5,280
Total assets	127,534		139,331		134,891			139,331	134,891	127,534
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4								(68)	183	1,692
Impairment charges								$ 0	251	2
Gain (loss) on termination of leveraged leases	93
Gain (loss) on termination of leveraged leases, after tax	$ 99
Number of international projects subject to leveraged lease terminated \| project	2							2
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								$ 4,702	5,962	4,380
Operating Segments \| Electric Utilities
Segment Reporting Information [Line Items]
Total operating revenues								19,998	22,873	18,300
Depreciation and amortization								3,865	3,029	2,953
Interest income								76	47	21
Earnings from equity method investments								(1)	0	1
Interest expense								1,274	1,067	968
Income taxes (benefit)								583	848	219
Segment net income (loss)								3,994	3,672	2,247
Goodwill	$ 2		2		2			2	2	2
Total assets	101,774		112,645		108,283			112,645	108,283	101,774
Operating Segments \| Traditional Electric Operating Companies
Segment Reporting Information [Line Items]
Total operating revenues								18,358	20,408	16,614
Depreciation and amortization								3,361	2,513	2,436
Interest income								69	44	20
Earnings from equity method investments								(1)	0	1
Interest expense								1,145	929	821
Income taxes (benefit)								571	828	232
Segment net income (loss)								3,637	3,318	1,981
Goodwill	0		0		0			0	0	0
Total assets	89,051		100,429		95,861			100,429	95,861	89,051
Operating Segments \| Southern Power
Segment Reporting Information [Line Items]
Total operating revenues								2,189	3,369	2,216
Depreciation and amortization								504	516	517
Interest income								7	3	1
Earnings from equity method investments								0	0	0
Interest expense								129	138	147
Income taxes (benefit)								12	20	(13)
Segment net income (loss)								357	354	266
Goodwill	2		2		2			2	2	2
Total assets	13,390		12,761		13,081			12,761	13,081	13,390
Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								4,702	5,962	4,380
Depreciation and amortization								582	559	536
Interest income								9	3	0
Earnings from equity method investments								140	148	50
Interest expense								310	263	238
Income taxes (benefit)								211	180	275
Segment net income (loss)								615	572	539
Goodwill	5,015		5,015		5,015			5,015	5,015	5,015
Total assets	23,560		25,083		24,621			25,083	24,621	23,560
Operating Segments \| All Other
Segment Reporting Information [Line Items]
Total operating revenues								718	593	582
Depreciation and amortization								78	75	76
Interest income								26	16	4
Earnings from equity method investments								5	3	24
Interest expense								879	694	631
Income taxes (benefit)								(298)	(233)	(227)
Segment net income (loss)								(635)	(711)	(384)
Goodwill	263		144		144			144	144	263
Total assets	2,975		2,446		2,665			2,446	2,665	2,975
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total operating revenues								(165)	(149)	(149)
Depreciation and amortization								0	0	0
Interest income								(26)	(7)	(3)
Earnings from equity method investments								0	0	1
Interest expense								(17)	(2)	0
Income taxes (benefit)								0	0	0
Segment net income (loss)								2	(9)	(9)
Goodwill	0		0		0			0	0	0
Total assets	(775)		(843)		(678)			(843)	(678)	(775)
Intersegment Eliminations \| Electric Utilities
Segment Reporting Information [Line Items]
Total operating revenues								(549)	(904)	(530)
Depreciation and amortization								0	0	0
Interest income								0	0	0
Earnings from equity method investments								0	0	0
Interest expense								0	0	0
Income taxes (benefit)								0	0	0
Segment net income (loss)								0	0	0
Goodwill	0		0		0			0	0	0
Total assets	(667)		(545)		(659)			(545)	(659)	(667)
Georgia Power
Segment Reporting Information [Line Items]
Total operating revenues								10,118	11,584	9,260
Depreciation and amortization								1,681	1,430	1,371
Interest expense								626	485	421
Income taxes (benefit)								448	370	(168)
Total assets			56,817		53,163			56,817	53,163
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4								(68)	183	1,692
Georgia Power \| Traditional Electric Operating Companies \| Plant Vogtle Units 3 and 4
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4								(68)	183	1,700
Estimated loss on Plant Vogtle Units 3 and 4, net of tax								(50)	137	1,300
Southern Power
Segment Reporting Information [Line Items]
Total operating revenues								2,189	3,369	2,216
Depreciation and amortization								504	516	517
Interest expense								129	138	147
Income taxes (benefit)								12	20	(13)
Segment net income (loss)								357	354	266
Total assets			12,761		13,081			12,761	13,081
Segment and Related Information (Textual) [Abstract]
Amount awarded from other party								9
Gain (loss) on dispositions								20	2	41
Southern Power \| Southern Power vs First Solar \| Settled Litigation
Segment and Related Information (Textual) [Abstract]
Litigation settlement								18
Southern Power \| Wind Generating Facility
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions								37		37
Gain (loss) on dispositions, after tax								28
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								4,702	5,962	4,380
Depreciation and amortization								582	559	536
Earnings from equity method investments								140	148	50
Interest expense								310	263	238
Income taxes (benefit)								211	180	275
Segment net income (loss)								615	572	539
Goodwill			5,015		5,015			5,015	5,015
Total assets	23,560		25,083		24,621			25,083	24,621	23,560
Segment and Related Information (Textual) [Abstract]
Estimated loss on regulatory disallowance								(96)	0	0
Gain (loss) on dispositions								7	4	127
Impairment charges								0	131	0
Southern Company Gas \| PennEast Pipeline
Segment Reporting Information [Line Items]
Earnings from equity method investments								0	0	(81)
Income taxes (benefit)										7
Segment and Related Information (Textual) [Abstract]
Impairment charges						$ 2	$ 82	84		84
Impairment charges, after tax						$ 2	$ 58	67		67
Southern Company Gas \| Operating Segments
Segment Reporting Information [Line Items]
Total operating revenues								4,685	5,937	4,374
Depreciation and amortization								581	537	505
Earnings from equity method investments								140	148	50
Interest expense								310	259	237
Income taxes (benefit)								195	217	213
Segment net income (loss)								630	671	626
Total assets	23,971		26,055		25,233			26,055	25,233	23,971
Southern Company Gas \| Operating Segments \| All Other
Segment Reporting Information [Line Items]
Total operating revenues								36	55	38
Depreciation and amortization								1	22	31
Earnings from equity method investments								0	0	0
Interest expense								0	4	1
Income taxes (benefit)								16	(37)	62
Segment net income (loss)								(15)	(99)	(87)
Total assets	12,114		9,675		8,943			9,675	8,943	12,114
Southern Company Gas \| Intersegment Eliminations
Segment Reporting Information [Line Items]
Total operating revenues								(19)	(30)	(32)
Depreciation and amortization								0	0	0
Earnings from equity method investments								0	0	0
Interest expense								0	0	0
Income taxes (benefit)								0	0	0
Segment net income (loss)								0	0	0
Total assets	$ (12,525)		(10,647)		(9,555)			(10,647)	$ (9,555)	(12,525)
Nicor Gas
Segment and Related Information (Textual) [Abstract]
Estimated loss on regulatory disallowance			(58)	$ (38)				96
Estimated loss on regulatory disallowance, after tax			$ (44)	$ (28)				72
Spare Parts \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Southern Power
Segment and Related Information (Textual) [Abstract]
Gain on sale								16
Gain on sale, after tax								12
Natural Gas Storage Facilities \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Southern Company Gas
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions					(131)
Gain (loss) on dispositions, after tax					$ (99)
Sequent \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Southern Company Gas
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions		$ 121						121		121
Gain (loss) on dispositions, after tax		92						92		92
Deferred tax expense, increase from change in appointment rate		$ 85						$ 85		$ 85

SEGMENT AND RELATED INFORMATI_5

SEGMENT AND RELATED INFORMATION - Electric Utilities' Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue from External Customer [Line Items]
Total operating revenues	$ 25,253	$ 29,279	$ 23,113
Wholesale electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	2,467	3,641	2,455
Electric Utilities
Revenue from External Customer [Line Items]
Total operating revenues	19,998	22,873	18,300
Electric Utilities \| Retail electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	16,343	18,197	14,852
Electric Utilities \| Wholesale electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	2,467	3,641	2,455
Electric Utilities \| Other
Revenue from External Customer [Line Items]
Total operating revenues	$ 1,188	$ 1,035	$ 993

SEGMENT AND RELATED INFORMATI_6

SEGMENT AND RELATED INFORMATION - Gas Revenues (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Jul. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating revenues				$ 25,253	$ 29,279	$ 23,113
Depreciation and amortization				4,525	3,663	3,565
Operating income (loss)				5,826	5,370	3,698
Earnings from equity method investments				144	151	76
Interest expense				2,446	2,022	1,837
Income taxes (benefit)				496	795	267
Segment net income (loss)				3,976	3,524	2,393
Total assets				139,331	134,891	127,534
Impairment charges				0	251	2
Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				4,702	5,962	4,380
Depreciation and amortization				582	559	536
Operating income (loss)				939	814	1,055
Earnings from equity method investments				140	148	50
Interest expense				310	263	238
Income taxes (benefit)				211	180	275
Segment net income (loss)				615	572	539
Total assets				25,083	24,621	23,560
Impairment charges				0	131	0
Gain on dispositions, net				7	4	127
Southern Company Gas \| Disposal Group, Disposed of by Sale, Not Discontinued Operations \| Sequent
Segment Reporting Information [Line Items]
Deferred tax expense, increase from change in appointment rate	$ 85			85		85
Gain on dispositions, net	121			121		121
Gain (loss) on dispositions, after tax	$ 92			92		92
Southern Company Gas \| PennEast Pipeline
Segment Reporting Information [Line Items]
Earnings from equity method investments				0	0	(81)
Income taxes (benefit)						7
Impairment charges		$ 2	$ 82	84		84
Impairment charges, after tax		$ 2	$ 58	67		67
Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				4,685	5,937	4,374
Depreciation and amortization				581	537	505
Operating income (loss)				956	957	1,095
Earnings from equity method investments				140	148	50
Interest expense				310	259	237
Income taxes (benefit)				195	217	213
Segment net income (loss)				630	671	626
Total assets				26,055	25,233	23,971
Intersegment Eliminations
Segment Reporting Information [Line Items]
Operating revenues				(165)	(149)	(149)
Depreciation and amortization				0	0	0
Earnings from equity method investments				0	0	1
Interest expense				(17)	(2)	0
Income taxes (benefit)				0	0	0
Segment net income (loss)				2	(9)	(9)
Total assets				(843)	(678)	(775)
Intersegment Eliminations \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				(19)	(30)	(32)
Depreciation and amortization				0	0	0
Operating income (loss)				(13)	(8)	0
Earnings from equity method investments				0	0	0
Interest expense				0	0	0
Income taxes (benefit)				0	0	0
Segment net income (loss)				0	0	0
Total assets				(10,647)	(9,555)	(12,525)
Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				4,702	5,962	4,380
Southern Company Gas \| Gas distribution operations
Segment Reporting Information [Line Items]
Operating revenues				4,090	5,240	3,656
Southern Company Gas \| Gas marketing services
Segment Reporting Information [Line Items]
Operating revenues				548	638	475
Southern Company Gas \| Other Gas Revenue
Segment Reporting Information [Line Items]
Operating revenues				64	84	249
Southern Company Gas \| Operating Segments
Segment Reporting Information [Line Items]
Operating revenues				4,702	5,962	4,380
Depreciation and amortization				582	559	536
Earnings from equity method investments				140	148	50
Interest expense				310	263	238
Income taxes (benefit)				211	180	275
Segment net income (loss)				615	572	539
Total assets				25,083	24,621	23,560
Wholesale gas services \| Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				0	0	188
Depreciation and amortization				0	0	0
Operating income (loss)				0	0	241
Earnings from equity method investments				0	0	0
Interest expense					0	2
Income taxes (benefit)				0	0	32
Segment net income (loss)				0	0	107
Total assets				0	0	31
Less Gross Gas Costs						3,783
Wholesale gas services \| Operating Segments \| Third Party Gross Revenues \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues						3,881
Wholesale gas services \| Operating Segments \| Intercompany Revenues \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues						90
Wholesale gas services \| Operating Segments \| Total Gross Revenues \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues						3,971
Gas distribution operations \| Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				4,105	5,267	3,679
Depreciation and amortization				561	516	482
Operating income (loss)				804	803	708
Earnings from equity method investments				0	0	0
Interest expense				275	229	207
Income taxes (benefit)				126	145	120
Segment net income (loss)				441	470	412
Total assets				22,906	22,040	20,917
Gas Pipeline Investments \| Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				32	32	32
Depreciation and amortization				5	5	5
Operating income (loss)				22	21	21
Earnings from equity method investments				140	148	50
Interest expense				32	27	25
Income taxes (benefit)				32	35	27
Segment net income (loss)				98	107	19
Total assets				1,534	1,577	1,467
Gas marketing services \| Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				548	638	475
Depreciation and amortization				15	16	18
Operating income (loss)				130	133	125
Earnings from equity method investments				0	0	0
Interest expense				3	3	3
Income taxes (benefit)				37	37	34
Segment net income (loss)				91	94	88
Total assets				1,615	1,616	1,556
All Other \| Operating Segments
Segment Reporting Information [Line Items]
Operating revenues				718	593	582
Depreciation and amortization				78	75	76
Earnings from equity method investments				5	3	24
Interest expense				879	694	631
Income taxes (benefit)				(298)	(233)	(227)
Segment net income (loss)				(635)	(711)	(384)
Total assets				2,446	2,665	2,975
All Other \| Operating Segments \| Southern Company Gas
Segment Reporting Information [Line Items]
Operating revenues				36	55	38
Depreciation and amortization				1	22	31
Operating income (loss)				(4)	(135)	(40)
Earnings from equity method investments				0	0	0
Interest expense				0	4	1
Income taxes (benefit)				16	(37)	62
Segment net income (loss)				(15)	(99)	(87)
Total assets				$ 9,675	$ 8,943	$ 12,114

VALUATION AND QUALIFYING ACCO_2

VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Provision for uncollectible accounts:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 71	$ 78	$ 118
Charged to Income	87	71	51
Charged to Other Accounts	3	(1)	(23)
Deductions	93	77	68
Balance at End of Period	68	71	78	$ 118
Provision for uncollectible accounts: \| Alabama Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	14	14	43
Charged to Income	16	10	(7)
Charged to Other Accounts	0	0	0
Deductions	14	10	22
Balance at End of Period	16	14	14	43
Provision for uncollectible accounts: \| Georgia Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	3	2	26
Charged to Income	26	21	16
Charged to Other Accounts	0	0	(23)	23
Deductions	25	20	17
Balance at End of Period	4	3	2	26
Provision for uncollectible accounts: \| Mississippi Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	1	1	1
Charged to Income	2	1	1
Charged to Other Accounts	0	1	0
Deductions	2	2	1
Balance at End of Period	1	1	1	1
Provision for uncollectible accounts: \| Southern Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	1	5	0
Charged to Income	0	(2)	5
Charged to Other Accounts	0	0	0
Deductions	0	2	0
Balance at End of Period	1	1	5	0
Provision for uncollectible accounts: \| Southern Company Gas
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	50	39	40
Charged to Income	43	55	26
Charged to Other Accounts	3	0	0
Deductions	52	44	27
Balance at End of Period	44	50	39	40
Tax valuation allowance (net state)
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	207	169	112
Charged to Income	(14)	68	57
Charged to Other Accounts	(25)	(30)	0
Deductions	0	0	0
Balance at End of Period	168	207	169	112
Tax valuation allowance (net state) \| Georgia Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	98	58	28
Charged to Income	(15)	70	30
Charged to Other Accounts	(23)	(30)	0
Deductions	0	0	0
Balance at End of Period	60	98	58	28
Tax valuation allowance (net state) \| Mississippi Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	32	32	32
Charged to Income	0	0	0
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Balance at End of Period	32	32	32	32
Tax valuation allowance (net state) \| Southern Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	21	21	27
Charged to Income	0	0	(6)
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Balance at End of Period	21	21	21	27
Tax valuation allowance (net state) \| Southern Company Gas
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	7	7	4
Charged to Income	0	0	3
Charged to Other Accounts	(2)	0	0
Deductions	0	0	0
Balance at End of Period	$ 5	$ 7	$ 7	$ 4