MDU Resources (MDU) 10-Q2 May 242024 Q1 Quarterly reportFinancial data

Company Profile

Cover Page

Cover Page - shares	3 Months Ended
Cover Page - shares	Mar. 31, 2024	Apr. 25, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2024
Document Transition Report	false
Entity File Number	1-03480
Entity Registrant Name	MDU RESOURCES GROUP INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	30-1133956
Entity Address, Address Line One	1200 West Century Avenue
Entity Address, Address Line Two	P.O. Box 5650
Entity Address, City or Town	Bismarck
Entity Address, State or Province	ND
Entity Address, Postal Zip Code	58506-5650
City Area Code	701
Local Phone Number	530-1000
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	MDU
Security Exchange Name	NYSE
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
Entity Shell Company	false
Entity common stock, shares outstanding		203,888,237
Entity Central Index Key	0000067716
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Operating revenues:
Operating revenues:	$ 1,213,825	$ 1,430,098
Operating expenses:
Total operation and maintenance	671,917	796,545
Purchased natural gas sold	258,602	371,015
Depreciation and amortization	55,750	52,233
Taxes, other than income	58,992	67,428
Electric fuel and purchased power	32,617	24,356
Total operating expenses	1,077,878	1,311,577
Operating income	135,947	118,521
Other income	13,787	10,374
Interest expense	28,706	23,953
Income before income taxes	121,028	104,942
Income taxes	20,130	21,067
Income from continuing operations	100,898	83,875
Discontinued operations, net of tax	0	(45,522)
Net income	$ 100,898	$ 38,353
Earnings per share - basic:
Income from continuing operations (in usd per share)	$ 0.50	$ 0.41
Discontinued operations, net of tax (in usd per share)	0	(0.22)
Earnings per share - basic (in usd per share)	0.50	0.19
Earnings per share - diluted:
Income from continuing operations (in usd per share)	0.49	0.41
Discontinued operations, net of tax (in usd per share)	0	(0.22)
Earnings per share - diluted (in usd per share)	$ 0.49	$ 0.19
Weighted average common shares outstanding - basic (in shares)	203,779	203,624
Weighted average common shares outstanding - diluted (in shares)	204,187	203,910
Regulated operation
Operating revenues:
Operating revenues:	$ 586,017	$ 673,932
Operating expenses:
Total operation and maintenance	105,680	102,041
Income from continuing operations	73,343	64,464
Nonregulated operation
Operating revenues:
Operating revenues:	627,808	756,166
Operating expenses:
Total operation and maintenance	566,237	694,504
Income from continuing operations	$ 27,555	$ 19,411

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 100,898	$ 38,353
Other comprehensive income:
Reclassification adjustment for loss on derivative instruments included in net income, net of tax of $11 for the three months ended 2023	0	34
Postretirement liability adjustment:
Amortization of postretirement liability losses included in net periodic benefit credit, net of tax of $34 and $34 for the three months ended in 2024 and 2023, respectively	104	100
Net unrealized gain (loss) on available-for-sale investments:
Net unrealized (loss) gain on available-for-sale investments arising during the period, net of tax of $(10) and $19 for the three months ended in 2024 and 2023, respectively	(36)	70
Reclassification adjustment for loss on available-for-sale investments included in net income, net of tax of $2 and $3 for the three months ended in 2024 and 2023, respectively	6	13
Net unrealized (loss) gain on available-for-sale investments	(30)	83
Other comprehensive income	74	217
Comprehensive income attributable to common stockholders	$ 100,972	$ 38,570

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Current assets:
Cash, cash equivalents and restricted cash	$ 89,296	$ 76,975	$ 85,971
Receivables, net	932,146	942,782	1,086,385
Current regulatory assets	158,614	172,492	216,318
Inventories	57,429	87,392	52,619
Prepayments and other current assets	82,459	84,082	46,525
Current assets of discontinued operations	0	0	620,896
Total current assets	1,319,944	1,363,723	2,108,714
Noncurrent assets:
Property, plant and equipment	7,441,589	7,341,116	6,962,954
Less accumulated depreciation and amortization	2,262,789	2,220,206	2,127,607
Net property, plant and equipment	5,178,800	5,120,910	4,835,347
Goodwill	488,960	488,960	488,960
Other intangible assets, net	1,482	2,004	3,571
Regulatory assets	414,433	447,099	349,500
Investments	119,396	124,235	136,924
Operating lease right-of-use assets	76,223	74,363	74,057
Other	240,633	211,865	157,903
Noncurrent assets of discontinued operations	0	0	1,687,611
Total noncurrent assets	6,519,927	6,469,436	7,733,873
Total assets	7,839,871	7,833,159	9,842,587
Current liabilities:
Short-term borrowings	0	95,000	293,500
Long-term debt due within one year	60,700	61,319	47,819
Accounts payable	420,168	475,215	429,014
Taxes payable	81,972	58,110	75,316
Dividends payable	25,044	25,461	45,306
Accrued compensation	47,394	85,512	51,499
Operating lease liabilities due within one year	23,134	22,884	21,994
Regulatory liabilities due within one year	90,115	70,761	44,395
Other accrued liabilities	174,296	181,471	178,771
Current liabilities of discontinued operations	0	0	448,715
Total current liabilities	922,823	1,075,733	1,636,329
Noncurrent liabilities:
Long-term debt	2,325,697	2,236,904	2,191,898
Deferred income taxes	461,808	458,548	467,007
Asset retirement obligations	388,451	384,371	376,085
Regulatory liabilities	523,484	521,050	454,669
Operating lease liabilities	53,204	51,645	52,619
Other	183,463	199,675	191,513
Noncurrent liabilities of discontinued operations	0	0	897,085
Total noncurrent liabilities	3,936,107	3,852,193	4,630,876
Commitments and contingencies
Stockholders' equity:
Common stock Authorized - 500,000,000 shares, $1.00 par value Shares issued - 203,888,237 at March 31, 2024, 204,162,814 at March 31, 2023 and 203,689,090 at December 31, 2023	203,888	203,689	204,163
Other paid-in capital	1,466,551	1,466,235	1,461,294
Retained earnings	1,328,812	1,253,693	1,943,917
Accumulated other comprehensive loss	(18,310)	(18,384)	(30,366)
Treasury stock at cost - 538,921 shares at March 31, 2023	0	0	(3,626)
Total stockholders' equity	2,980,941	2,905,233	3,575,382
Total liabilities and stockholders' equity	$ 7,839,871	$ 7,833,159	$ 9,842,587

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Stock	Other Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock
Common stock, beginning balance (in shares) at Dec. 31, 2022		204,162,814
Beginning balance at Dec. 31, 2022	$ 3,587,129	$ 204,163	$ 1,466,037	$ 1,951,138	$ (30,583)	$ (3,626)
Treasury stock, common, beginning balance (in shares) at Dec. 31, 2022						(538,921)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	38,353			38,353
Other comprehensive income	217				217
Dividends declared on common stock	(45,574)			(45,574)
Stock-based compensation	3,108		3,108
Repurchase of common stock (in shares)						(153,622)
Repurchase of common stock	(4,811)					$ (4,811)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings (in shares)						153,622
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	$ (3,040)		(7,851)			$ 4,811
Common stock, ending balance (in shares) at Mar. 31, 2023	204,162,814	204,162,814
Ending balance at Mar. 31, 2023	$ 3,575,382	$ 204,163	1,461,294	1,943,917	(30,366)	$ (3,626)
Treasury stock, common, ending balance (in shares) at Mar. 31, 2023	(538,921)					(538,921)
Common stock, beginning balance (in shares) at Dec. 31, 2023	203,689,090	203,689,090
Beginning balance at Dec. 31, 2023	$ 2,905,233	$ 203,689	1,466,235	1,253,693	(18,384)	$ 0
Treasury stock, common, beginning balance (in shares) at Dec. 31, 2023						0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	100,898			100,898
Other comprehensive income	74				74
Dividends declared on common stock	(25,779)			(25,779)
Stock-based compensation	3,173		3,173
Issuance of common stock	(35)		(35)
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings (in shares)		199,147				0
Issuance of common stock upon vesting of stock-based compensation, net of shares used for tax withholdings	$ (2,623)	$ 199	(2,822)			$ 0
Common stock, ending balance (in shares) at Mar. 31, 2024	203,888,237	203,888,237
Ending balance at Mar. 31, 2024	$ 2,980,941	$ 203,888	$ 1,466,551	$ 1,328,812	$ (18,310)	$ 0
Treasury stock, common, ending balance (in shares) at Mar. 31, 2024						0

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Operating activities:
Net income		$ 100,898	$ 38,353
Discontinued operations, net of tax		0	(45,522)
Income from continuing operations		100,898	83,875
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization		55,750	52,233
Deferred income taxes		1,059	9,613
Provision for credit losses		2,287	3,765
Amortization of debt issuance costs		228	248
Employee stock-based compensation costs		3,173	2,655
Pension and postretirement benefit plan net periodic benefit credit		(964)	(1,392)
Unrealized gains on investments		(2,873)	(3,066)
Gains on sales of assets		(1,276)	(1,545)
Changes in current assets and liabilities, net of acquisitions:
Receivables		12,283	(19,299)
Inventories		28,127	9,053
Other current assets		36,570	(41,319)
Accounts payable		(41,468)	(96,054)
Other current liabilities		(3,889)	50,322
Pension and postretirement benefit plan contributions		(8)	(9)
Other noncurrent changes		(24,800)	(11,380)
Net cash provided by continuing operations		165,097	37,700
Net cash used in discontinued operations		0	(81,348)
Net cash provided by (used in) operating activities		165,097	(43,648)
Investing activities:
Capital expenditures		(126,209)	(111,641)
Net proceeds from sale or disposition of property		2,820	3,169
Salvage value, net of cost of removal		31	892
Investments		(2,906)	(2,690)
Proceeds from investment cost basis withdrawal		9,000	0
Net cash used in continuing operations		(117,264)	(110,270)
Net cash used in discontinued operations		0	(40,754)
Net cash used in investing activities		(117,264)	(151,024)
Financing activities:
Issuance of short-term borrowings		0	275,000
Repayment of short-term borrowings		(95,000)	(20,000)
Issuance of long-term debt		89,200	43,835
Repayment of long-term debt		(623)	(169,823)
Debt issuance costs		(527)	(93)
Costs of issuance of common stock		(35)	0
Dividends paid		(25,904)	(45,246)
Repurchase of common stock		0	(4,811)
Tax withholding on stock-based compensation		(2,623)	(3,040)
Net cash (used in) provided by continuing operations		(35,512)	75,822
Net cash provided by discontinued operations		0	131,522
Net cash (used in) provided by financing activities		(35,512)	207,344
Increase in cash, cash equivalents and restricted cash		12,321	12,672
Cash, cash equivalents and restricted cash - beginning of year		76,975	80,517
Cash, cash equivalents and restricted cash - end of period *	[1]	$ 89,296	$ 93,189

[1]Includes cash of discontinued operations of $7.2 million at March 31, 2023.

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Reclassification adjustment for loss on derivative instruments included in net income, tax		$ 11
Amortization of postretirement liability losses included in net periodic benefit credit, tax	$ 34	34
Net unrealized gain (loss) on available-for-sale investments arising during the period, tax	(10)	19
Reclassification adjustment for loss on available-for-sale investments included in net income, tax	$ 2	$ 3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Statement of Financial Position [Abstract]
Common stock, authorized (in shares)	500,000,000	500,000,000	500,000,000
Common stock, par value per share (in usd per share)	$ 1	$ 1	$ 1
Common stock, issued (in shares)	203,888,237	203,689,090	204,162,814
Treasury stock, common (in shares)			538,921

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) $ in Millions	Mar. 31, 2023 USD ($)
Statement of Cash Flows [Abstract]
Disposal group, including discontinued operation, cash and cash equivalents	$ 7.2

Basis of presentation

Basis of presentation	3 Months Ended
Basis of presentation	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	Basis of presentation The accompanying consolidated interim financial statements were prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with those appearing in the 2023 Annual Report. The information is unaudited but includes all adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Depreciation and amortization expense is reported separately on the Consolidated Statements of Income and therefore is excluded from the other line items within operating expenses. On May 31, 2023, the Company completed the separation of Knife River, formerly the construction materials and contracting segment, which resulted in two independent, publicly traded companies, MDU Resources Group, Inc. and Knife River. The Company's board of directors approved the distribution of approximately 90 percent of the issued and outstanding shares of Knife River to the Company's stockholders. Stockholders of the Company received one share of Knife River common stock for every four shares of the Company's common stock held on May 22, 2023, the record date for the distribution. The Company retained approximately 10 percent or 5.7 million shares of Knife River common stock immediately following the separation, which were disposed of in a tax-free exchange in November 2023. The separation of Knife River was a tax-free spinoff transaction to the Company's stockholders for U.S. federal income tax purposes. The Company's consolidated financial statements and accompanying notes for the current and prior periods have been restated to present the results of operations and the assets and liabilities of Knife River as discontinued operations, other than certain corporate overhead costs of the Company historically allocated to Knife River, which are reflected in Other. Also included in discontinued operations in the Consolidated Statements of Income are the supporting activities of Fidelity and certain interest expense related to financing activity associated with the Knife River separation. The assets and liabilities of the Company's discontinued operations are included in current assets of discontinued operations, noncurrent assets of discontinued operations, current liabilities of discontinued operations and noncurrent liabilities of discontinued operations on the Consolidated Balance Sheets. Unless otherwise indicated, the amounts presented in the accompanying notes to the consolidated financial statements relate to the Company's continuing operations. For more information on discontinued operations, see Note 3. On November 2, 2023, the Company announced its intent to pursue a tax-free spinoff of its wholly owned construction services business, MDU Construction Services. On March 13, 2024, the Company announced its construction services business, MDU Construction Services, rebranded to Everus Construction. The Company's board of directors believes a tax-free spinoff of the construction services business supports the Company's goal of enhancing value for stockholders by becoming a pure-play regulated energy delivery company. The separation will occur by means of a tax-free spinoff of a newly formed company, Everus, which will own the assets and liabilities of Everus Construction.

New accounting standards

New accounting standards	3 Months Ended
New accounting standards	Mar. 31, 2024
Accounting Standards Update and Change in Accounting Principle [Abstract]
New accounting standards	New accounting standards The following table provides a brief description of the accounting pronouncements applicable to the Company and the potential impact on its Consolidated Financial Statements and/or disclosures: Standard Description Effective date Impact on financial statements/disclosures Recently adopted accounting standards ASU 2022-06 - Reference Rate Reform: Deferral of Sunset Date In December 2022, the FASB included a sunset provision within ASC 848 based on expectations of when LIBOR would cease being published. At the time ASU 2020-04 was issued, the UK Financial Conduct Authority had established its intent to cease overnight tenors of LIBOR after December 31, 2021. In March 2021, the UK Financial Conduct Authority announced that the intended cessation date of the overnight tenors of LIBOR would be June 30, 2023 which is beyond the current sunset date of ASC 848. The amendments in this Update defer the sunset date of ASC 848 from December 31, 2022 to December 31, 2024, after which entities will no longer be permitted to apply the relief in ASC 848. December 31, 2024 The Company has updated its credit agreements to include language regarding the successor or alternate rate to LIBOR. The Company does not expect the guidance to have a material impact on its results of operations, financial position, cash flows or disclosures. Recently issued accounting standards not yet adopted ASU 2023-05 Business Combinations - Joint Venture Formations - Recognition and Initial Measurement In August 2023, the FASB issued guidance on accounting for contributions made to a joint venture, upon formation, in a joint venture's separate financial statement in order to provide decision-useful information to investors and other allocators of capital (collectively investors) in a joint venture's financial statements and reduce diversity in practice. The new basis of accounting will require that a joint venture, upon formation, will recognize and initially measure its assets and liabilities at fair value (with the exceptions to fair value measurement that are consistent with the business combinations guidance). A joint venture that was formed before January 1, 2025 may elect to apply the guidance retrospectively if it has sufficient information. Effective prospectively for all joint venture formations with a formation date on or after January 1, 2025. The Company is currently evaluating the impact the guidance will have on its interim and annual disclosures for the year ended December 31, 2025. ASU 2023-07 Segment Reporting - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued guidance on improving financial reporting by requiring disclosure of incremental segment information, primarily through enhanced disclosures about significant segment expenses, on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. Effective for fiscal year December 31, 2024 and interim periods beginning January 1, 2025, with prior periods disclosed in the period of adoption. The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2024 and future interim periods. ASU 2023-09 Income Taxes - Improvements to Income Tax Disclosures an Amendment, December 2023 The FASB issued guidance to address investors requests for more transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information and effectiveness of income tax disclosures. December 31, 2025 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025. ASU 2024-01 Compensation - Stock Compensation This FASB issued improvements to GAAP through an example to demonstrate application of the scope of paragraph 718-10-15-3 to determine whether profits interest and similar awards should be accounted in Compensation - Stock Compensation. Effective for fiscal year beginning after December 15, 2024. The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025.

Discontinued operations

Discontinued operations	3 Months Ended
Discontinued operations	Mar. 31, 2024
Discontinued Operations and Disposal Groups [Abstract]
Discontinued operations	Discontinued operations On May 31, 2023, the Company completed the previously announced separation of Knife River, its former construction materials and contracting segment, into a new publicly traded company. The separation was achieved through the Company's pro-rata distribution of approximately 90 percent of the outstanding shares of Knife River to the Company's common stockholders. To effect the separation, the Company distributed to its stockholders one share of Knife River common stock for every four shares of the Company's common stock held on May 22, 2023, the record date for the distribution, with the Company retaining approximately 10 percent, or 5.7 million shares of Knife River common stock immediately following the separation. In the fourth quarter of 2023, the Company completed the tax-free exchange of its retained shares. As a result of the separation, the historical assets and liabilities for Knife River have been classified as assets and liabilities of discontinued operations and the historical results of operations are shown in discontinued operations, net of tax, other than allocated general corporate overhead costs of the Company, which do not meet the criteria for income (loss) from discontinued operations. The Company’s consolidated financial statements and accompanying notes for prior periods have been restated. On April 25, 2023, Knife River issued $425.0 million of senior notes, pursuant to an indenture, due in 2031 to qualified institutional buyers. Knife River also entered into a new credit agreement which provided a revolving credit facility in an initial amount of up to $350.0 million and a senior secured term loan facility in an amount up to $275.0 million. The net proceeds from the notes offering, revolving credit facility and the term loan were used to repay $825.0 million of Knife River's intercompany obligations owed to Centennial. Centennial used the entirety of these proceeds from Knife River to repay a portion of its existing third-party indebtedness. As a result of the separation, the Company retained legal ownership of 538,921 shares of the Company's common stock that were historically owned by a subsidiary of Knife River and recorded in Treasury stock at cost. Following the separation, the 538,921 treasury shares were retired. The Company provided to Knife River and Knife River provided to the Company transition services in accordance with the TSA entered into on May 31, 2023. For the three months ended March 31, 2024, the Company received $1.0 million; and paid $78,200 , for these related activities. The majority of the transition services are expected to be provided for a period of one year, however, no longer than two years after the separation. Separation related costs of $4.3 million, net of tax, were incurred during the three months ended March 31, 2023. Separation costs incurred are presented in income (loss) from discontinued operations in the Consolidated Statements of Income. These charges primarily relate to transaction and third-party support costs, one-time business separation fees and related tax charges. The Company had no assets or liabilities related to the discontinued operations of Knife River on its balance sheet as of March 31, 2024 or December 31, 2023. The carrying amounts of the major classes of assets and liabilities of discontinued operations included in the Company’s Consolidated Balance Sheet at March 31, 2023 were as follows: March 31, 2023 Assets (In Thousands) Current assets: Cash and cash equivalents $ 7,218 Receivables, net 205,564 Inventories 373,215 Prepayments and other current assets 34,899 Total current assets of discontinued operations 620,896 Noncurrent assets: Net property, plant and equipment 1,317,368 Goodwill 274,540 Other intangible assets, net 12,763 Investments 35,542 Operating lease right-of-use assets 43,995 Other 3,403 Total noncurrent assets of discontinued operations 1,687,611 Total assets of discontinued operations $ 2,308,507 Liabilities Current liabilities: Short-term borrowings $ 208,000 Long-term debt due within one year 30,211 Accounts payable 118,175 Taxes payable (1,402) Accrued compensation 14,010 Operating lease liabilities due within one year 12,981 Other accrued liabilities 66,740 Total current liabilities of discontinued operations 448,715 Noncurrent liabilities: Long-term debt 577,138 Deferred income taxes 175,062 Asset retirement obligations 33,462 Operating lease liabilities 31,014 Other 80,409 Total noncurrent liabilities of discontinued operations 897,085 Total liabilities of discontinued operations $ 1,345,800 The reconciliation of the major classes of income and expense constituting pretax loss from discontinued operations to the after-tax loss from discontinued operations on the Consolidated Statements of Income were as follows: Three Months Ended March 31, 2023 (In thousands) Operating revenues $ 307,239 Operating expenses 351,274 Operating loss (44,035) Other income 493 Interest expense 14,067 Loss from discontinued operations before income taxes (57,609) Income taxes (12,087) Discontinued operations, net of tax $ (45,522)

Seasonality of operations

Seasonality of operations	3 Months Ended
Seasonality of operations	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Seasonality of operations	Seasonality of operations Some of the Company's operations are highly seasonal and revenues from, and certain expenses for, such operations may fluctuate significantly among quarterly periods. Accordingly, the interim results for particular businesses, and for the Company as a whole, may not be indicative of results for the full fiscal year.

Receivables and allowance for e

Receivables and allowance for expected credit losses	3 Months Ended
Receivables and allowance for expected credit losses	Mar. 31, 2024
Credit Loss [Abstract]
Receivables and allowance for expected credit loss	Receivables and allowance for expected credit losses Receivables consist primarily of trade and contracting services receivables from the sale of goods and services, net of expected credit losses. The Company's trade receivables are all due in 12 months or less. The total balance of receivables past due 90 days or more was $70.2 million, $39.8 million and $45.7 million at March 31, 2024 and 2023, and December 31, 2023, respectively. The Company's expected credit losses are determined through a review using historical credit loss experience; changes in asset specific characteristics; current conditions; and reasonable and supportable future forecasts, among other specific account data, and is performed at least quarterly. The Company develops and documents its methodology to determine its allowance for expected credit losses at each of its reportable business segments. Risk characteristics used by the business segments may include customer mix, knowledge of customers and general economic conditions of the various local economies, among others. Specific account balances are written off when management determines the amounts to be uncollectible. Management has reviewed the balance reserved through the allowance for expected credit losses and believes it is reasonable. Details of the Company's expected credit losses were as follows: Electric Natural gas Pipeline Construction Total (In thousands) At December 31, 2023 $ 414 $ 1,189 $ — $ 7,967 $ 9,570 Current expected credit loss provision 782 1,916 — (411) 2,287 Less write-offs charged against the allowance 659 1,455 — 48 2,162 Credit loss recoveries collected 147 314 — — 461 At March 31, 2024 $ 684 $ 1,964 $ — $ 7,508 $ 10,156 Electric Natural gas Pipeline Construction Total (In thousands) At December 31, 2022 $ 375 $ 1,615 $ 2 $ 2,162 $ 4,154 Current expected credit loss provision 615 2,324 — 826 3,765 Less write-offs charged against the allowance 667 1,225 — 51 1,943 Credit loss recoveries collected 145 229 — 1 375 At March 31, 2023 $ 468 $ 2,943 $ 2 $ 2,938 $ 6,351

Inventories and natural gas in

Inventories and natural gas in storage	3 Months Ended
Inventories and natural gas in storage	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories and natural gas in storage	Inventories and natural gas in storage Natural gas in storage for the Company's regulated operations is generally valued at lower of cost or market using the last-in, first-out method or lower of cost or net realizable value using the average cost or first-in, first-out method. The majority of all other inventories are valued at the lower of cost or net realizable value using the average cost method. The portion of the cost of natural gas in storage expected to be used within 12 months was included in inventories. Inventories on the Consolidated Balance Sheets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Merchandise for resale 38,280 29,934 34,955 Natural gas in storage (current) 9,309 8,662 39,377 Materials and supplies $ 3,636 $ 7,064 $ 5,460 Other 6,204 6,959 7,600 Total $ 57,429 $ 52,619 $ 87,392

Earnings per share

Earnings per share	3 Months Ended
Earnings per share	Mar. 31, 2024
Earnings Per Share [Abstract]
Earnings per share	Earnings per share Basic earnings per share is computed by dividing net income by the weighted average number of shares of common stock outstanding during the applicable period. Diluted earnings per share is computed by dividing net income by the total of the weighted average number of shares of common stock outstanding during the applicable period, plus the effect of non-vested performance share awards and restricted stock units. Common stock outstanding includes issued shares less shares held in treasury. Net income was the same for both the basic and diluted earnings per share calculations. A reconciliation of the weighted average common shares outstanding used in the basic and diluted earnings per share calculations follows: Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Weighted average common shares outstanding - basic 203,779 203,624 Effect of dilutive performance share awards and restricted stock units 408 286 Weighted average common shares outstanding - diluted 204,187 203,910 Earnings per share - basic: Income from continuing operations $ .50 $ .41 Discontinued operations, net of tax — (.22) Earnings per share - basic $ .50 $ .19 Earnings per share - diluted: Income from continuing operations $ .49 $ .41 Discontinued operations, net of tax — (.22) Earnings per share - diluted $ .49 $ .19 Shares excluded from the calculation of diluted earnings per share — — Dividends declared per common share 0.1250 $ .2225

Revenue from contracts with cus

Revenue from contracts with customers	3 Months Ended
Revenue from contracts with customers	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Revenue from contracts with customers	Revenue from contracts with customers Revenue is recognized when a performance obligation is satisfied by transferring control over a product or service to a customer. Revenue is measured based on consideration specified in a contract with a customer and excludes any sales incentives and amounts collected on behalf of third parties. The Company is considered an agent for certain taxes collected from customers. As such, the Company presents revenues net of these taxes at the time of sale to be remitted to governmental authorities, including sales and use taxes. As part of the adoption of ASC 606 - Revenue from Contracts with Customers , the Company elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the Company otherwise would have recognized is 12 months or less. The Company recognizes revenue from the sale of emissions allowances allocated under the environmental programs in certain states. The Company has the right to payment when the allowances are sold at auction. Revenue is recognized on a point in time basis within the quarter that the auction is held. The revenues associated with the sale of these allowances are deferred as a component of the respective jurisdiction’s regulatory asset or liability for environmental compliance. For more information on the Company’s regulatory assets and liabilities, see Note 10. Changes in cost estimates on certain contracts may result in the issuance of change orders, which can be approved or unapproved by the customer, or the assertion of contract claims. The Company recognizes amounts associated with change orders and claims as revenue if it is probable that the contract price will be adjusted and the amount of any such adjustment can be reasonably estimated. Change orders and claims are negotiated in the normal course of business and represent management’s estimates of additional contract revenues that have been earned and are probable of collection. The Company received notification in 2023 from a customer on a large project with a contract that was billed on a time and materials basis with no stated maximum price, that it is withholding payment of approximately $31.0 million on remaining outstanding billings, including retention. The Company believes it has substantial defenses against these claims based upon the terms of the contract and the Company's belief that it has fully performed under the terms of the contract. The Company believes collection of the remaining outstanding billings, including retention is probable and, as a result, the Company has recognized the revenue from this project in its results. However, there is uncertainty surrounding this matter, including the potential long-term nature of dispute resolution, the Company filing a lien on the property and the broad range of possible consideration amounts as a result of negotiations and potential litigation to resolve the dispute. Disaggregation In the following tables, revenue is disaggregated by the type of customer or service provided. The Company believes this level of disaggregation best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The table also includes a reconciliation of the disaggregated revenue by reportable segments. For more information on the Company's business segments, see Note 15. Three Months Ended March 31, 2024 Electric Natural gas Pipeline Construction Other Total (In thousands) Residential utility sales $ 39,222 $ 263,103 $ — $ — $ — $ 302,325 Commercial utility sales 41,515 162,130 — — — 203,645 Industrial utility sales 11,349 14,579 — — — 25,928 Other utility sales 1,936 — — — — 1,936 Natural gas transportation — 14,591 43,637 — — 58,228 Natural gas storage — — 5,382 — — 5,382 Electrical & mechanical specialty contracting — — — 439,378 — 439,378 Transmission & distribution specialty contracting — — — 176,860 — 176,860 Other 15,630 3,201 2,256 46 1,433 22,566 Intersegment eliminations (28) (56) (30,311) (87) (1,417) (31,899) Revenues from contracts with customers 109,624 457,548 20,964 616,197 16 1,204,349 Other revenues (1,897) 1,921 47 9,405 — 9,476 Total external operating revenues $ 107,727 $ 459,469 $ 21,011 $ 625,602 $ 16 $ 1,213,825 Three Months Ended March 31, 2023 Electric Natural gas Pipeline Construction Other Total (In thousands) Residential utility sales $ 37,825 $ 327,651 $ — $ — $ — $ 365,476 Commercial utility sales 36,347 204,927 — — — 241,274 Industrial utility sales 10,763 16,838 — — — 27,601 Other utility sales 1,774 — — — — 1,774 Natural gas transportation — 13,504 34,983 — — 48,487 Natural gas storage — — 3,861 — — 3,861 Electrical & mechanical specialty contracting — — — 590,263 — 590,263 Transmission & distribution specialty contracting — — — 152,022 — 152,022 Other 11,878 4,721 1,859 33 1,572 20,063 Intersegment eliminations (27) (70) (26,270) — (1,572) (27,939) Revenues from contracts with customers 98,560 567,571 14,433 742,318 — 1,422,882 Other revenues (2,863) (1,974) 38 12,015 — 7,216 Total external operating revenues $ 95,697 $ 565,597 $ 14,471 $ 754,333 $ — $ 1,430,098 Contract balances The timing of revenue recognition may differ from the timing of invoicing to customers. The timing of invoicing to customers does not necessarily correlate with the timing of revenues being recognized under the cost-to-cost method of accounting. Contracts from contracting services are billed as work progresses in accordance with agreed upon contractual terms. Generally, billing to the customer occurs contemporaneous to revenue recognition. A variance in timing of the billings may result in a contract asset or a contract liability. A contract asset occurs when revenues are recognized under the cost-to-cost measure of progress, which exceeds amounts billed on uncompleted contracts. Such amounts will be billed as standard contract terms allow, usually based on various measures of performance or achievement. A contract liability occurs when there are billings in excess of revenues recognized under the cost-to-cost measure of progress on uncompleted contracts. Contract liabilities decrease as revenue is recognized from the satisfaction of the related performance obligation. The changes in contract assets and liabilities were as follows: March 31, 2024 December 31, 2023 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 165,924 $ 158,861 $ 7,063 Receivables, net Contract liabilities - current (187,741) (202,144) 14,403 Accounts payable Contract liabilities - noncurrent (2,161) (291) (1,870) Noncurrent liabilities - other Net contract liabilities $ (23,978) $ (43,574) $ 19,596 The Company recognized $97.6 million in revenue for the three months ended March 31, 2024, which was previously included in contract liabilities at December 31, 2023. The Company recognized $134.6 million in revenue for the three months ended March 31, 2023, which was previously included in contract liabilities at December 31, 2022. The Company recognized a net increase in revenues of $33.4 million and $17.7 million for the three months ended March 31, 2024 and 2023, respectively, from performance obligations satisfied in prior periods. Remaining performance obligations The remaining performance obligations, also referred to as backlog, at the construction services segment include unrecognized revenues that the Company reasonably expects to be realized. These unrecognized revenues can include: projects that have a written award, a letter of intent, a notice to proceed, an agreed upon work order to perform work on mutually accepted terms and conditions and change orders or claims to the extent management believes additional contract revenues will be earned and are deemed probable of collection. Excluded from remaining performance obligations are potential orders under master service agreements. The majority of the Company's construction contracts have an original duration of less than two years. The remaining performance obligations at the pipeline segment include firm transportation and storage contracts with fixed pricing and fixed volumes. The Company has applied the practical expedient that does not require additional disclosures for contracts with an original duration of less than 12 months, to certain firm transportation, storage and non-regulated contracts. The Company's firm transportation and storage contracts included in the remaining performance obligations have weighted average remaining durations of less than five years and two years, respectively. At March 31, 2024, the Company's remaining performance obligations were $2.8 billion. The Company expects to recognize the following revenue amounts in future periods related to these remaining performance obligations: $1.8 billion within the next 12 months or less; $412.8 million within the next 13 to 24 months; and $530.6 million in 25 months or more.

Leases

Leases	3 Months Ended
Leases	Mar. 31, 2024
Leases [Abstract]
Leases	Leases The Company's leases primarily include operating leases for equipment, buildings, easements and vehicles. The Company leases certain equipment to third parties through its utility and construction services segments, which are considered short-term operating leases with terms of less than 12 months. The Company recognized revenue from operating leases of $9.5 million and $12.2 million for the three months ended March 31, 2024 and 2023, respectively. At March 31, 2024, the Company had $8.5 million of lease receivables with a majority due within 12 months.

Regulatory assets and liabiliti

Regulatory assets and liabilities	3 Months Ended
Regulatory assets and liabilities	Mar. 31, 2024
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory assets and liabilities	Regulatory assets and liabilities The following table summarizes the individual components of unamortized regulatory assets and liabilities: Estimated Recovery or Refund Period as of March 31, 2024 * March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Regulatory assets: Current: Natural gas costs recoverable through rate adjustments Up to 1 year $ 110,481 $ 198,166 $ 98,844 Electric fuel and purchased power deferral Up to 1 year 17,061 3,279 33,918 Conservation programs Up to 1 year 13,735 8,599 14,425 Environmental compliance programs Up to 1 year 7,443 1,191 5,525 Cost recovery mechanisms Up to 1 year 6,454 3,954 9,153 Other Up to 1 year 3,440 1,129 10,627 158,614 216,318 172,492 Noncurrent: Pension and postretirement benefits 142,511 143,349 142,511 Cost recovery mechanisms Up to 25 years 84,546 65,732 85,944 Environmental compliance programs - 50,372 21,942 66,806 Plant costs/asset retirement obligations Over plant lives 45,702 44,131 46,009 Natural gas costs recoverable through rate adjustments Up to 2 years 25,915 — 55,493 Manufactured gas plant site remediation - 25,851 26,605 26,127 Taxes recoverable from customers Over plant lives 12,331 12,198 12,249 Electric fuel and purchased power deferral Up to 2 years 15,612 — — Long-term debt refinancing costs Up to 36 years 2,453 3,041 2,600 Plant to be retired - 294 21,072 772 Other Up to 15 years 8,846 11,430 8,588 414,433 349,500 447,099 Total regulatory assets $ 573,047 $ 565,818 $ 619,591 Regulatory liabilities: Current: Natural gas costs refundable through rate adjustments Up to 1 year $ 54,282 $ 6,331 $ 43,161 Provision for rate refund Up to 1 year 6,517 1,115 6,866 Cost recovery mechanisms Up to 1 year 5,642 2,926 6,284 Conservation programs Up to 1 year 3,576 3,834 2,130 Margin sharing Up to 1 year 2,869 — 5,243 Taxes refundable to customers Up to 1 year 1,991 1,513 2,149 Refundable fuel and electric costs Up to 1 year 1,122 1,179 263 Electric fuel and purchased power deferral Up to 1 year 746 9,630 — Other Up to 1 year 13,370 17,867 4,665 90,115 44,395 70,761 Noncurrent: Plant removal and decommissioning costs Over plant lives 220,519 214,467 220,147 Taxes refundable to customers Over plant lives 190,850 200,879 193,578 Environmental compliance programs - 63,746 — 61,941 Cost recovery mechanisms Up to 18 years 24,269 16,313 21,791 Accumulated deferred investment tax credit Over plant lives 16,129 13,996 15,740 Pension and postretirement benefits 6,044 7,376 6,044 Other Up to 14 years 1,927 1,638 1,809 523,484 454,669 521,050 Total regulatory liabilities $ 613,599 $ 499,064 $ 591,811 Net regulatory position $ (40,552) $ 66,754 $ 27,780 * Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers. ** Recovered as expense is incurred or cash contributions are made. At March 31, 2024 and 2023, and December 31, 2023, approximately $191.7 million, $255.6 million and $194.3 million, respectively, of regulatory assets were not earning a rate of return; however, these regulatory assets are expected to be recovered from customers in future rates. These assets are largely comprised of the unfunded portion of pension and postretirement benefits, asset retirement obligations, certain pipeline integrity costs and the estimated future cost of manufactured gas plant site remediation. If, for any reason, the Company's regulated businesses cease to meet the criteria for application of regulatory accounting for all or part of their operations, the regulatory assets and liabilities relating to those portions ceasing to meet such criteria would be written off and included in the statement of income or accumulated other comprehensive loss in the period in which the discontinuance of regulatory accounting occurs.

Environmental allowances and ob

Environmental allowances and obligations	3 Months Ended
Environmental allowances and obligations	Mar. 31, 2024
Accounting Policies [Abstract]
Environmental allowances and obligations	Environmental allowances and obligations Beginning in 2023, the Company's natural gas distribution segment acquires environmental allowances as part of its requirement to comply with environmental regulations in certain states. Allowances are allocated by the respective states to the Company at no cost and additional allowances are required to be purchased as needed based on the requirements in the respective states. The segment records purchased and allocated environmental allowances at weighted average cost under the inventory method of accounting. Environmental allowances are included in prepayments and other current assets and noncurrent assets - other on the Consolidated Balance Sheets. Environmental compliance obligations, which are based on GHG emissions, are measured at the carrying value of environmental allowances held plus the estimated value of additional allowances necessary to satisfy the compliance obligation. Environmental compliance obligations are included in current liabilities - other accrued liabilities and noncurrent liabilities - other on the Consolidated Balance Sheets. The Company recognizes revenue from the sale of emissions allowances allocated under the environmental programs when the allowances are sold at auction. The revenues associated with the sale of these allowances are deferred as a component of the respective jurisdiction’s regulatory liability for environmental compliance. As environmental allowances are surrendered, the segment reduces the associated environmental compliance assets and liabilities from the Consolidated Balance Sheets. The expenses and revenues associated with the Company’s environmental allowances and obligations are deferred as regulatory assets and liabilities. For more information on the Company’s regulatory assets and liabilities, see Note 10.

Fair value measurements

Fair value measurements	3 Months Ended
Fair value measurements	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair value measurements	Fair value measurements Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. The fair value ASC establishes a hierarchy for grouping assets and liabilities, based on the significance of inputs. The estimated fair values of the Company's assets and liabilities measured on a recurring basis are determined using the market approach. The Company measures its investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income. The Company anticipates using these investments, which consist of insurance contracts, to satisfy its obligations under its unfunded, nonqualified defined benefit and defined contribution plans for executive officers and certain key management employees and invests in these fixed-income and equity securities for the purpose of earning investment returns and capital appreciation. These investments, which totaled $62.7 million, $83.5 million and $66.2 million, at March 31, 2024 and 2023, and December 31, 2023, respectively, are classified as investments on the Consolidated Balance Sheets. The net unrealized gain on these investments was $2.9 million for both the three months ended March 31, 2024 and 2023. The change in fair value, which is considered part of the cost of the plan, is classified in other income on the Consolidated Statements of Income. In the first quarter of 2024 and the fourth quarter of 2023 the Company withdrew $9.0 million and $20.0 million, respectively, of its cost basis, which reduced investments on the Consolidated Balance Sheets. The Company did not elect the fair value option, which records gains and losses in income, for its available-for-sale securities, which include mortgage-backed securities and U.S. Treasury securities. These available-for-sale securities are recorded at fair value and are classified as investments on the Consolidated Balance Sheets. Unrealized gains or losses are recorded in accumulated other comprehensive loss. Details of available-for-sale securities were as follows: March 31, 2024 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,072 $ 4 $ 507 $ 7,569 U.S. Treasury securities 3,756 35 2 3,789 Total $ 11,828 $ 39 $ 509 $ 11,358 March 31, 2023 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,557 $ 3 $ 561 $ 7,999 U.S. Treasury securities 3,023 8 51 2,980 Total $ 11,580 $ 11 $ 612 $ 10,979 December 31, 2023 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,234 $ 17 $ 470 $ 7,781 U.S. Treasury securities 3,521 28 8 3,541 Total $ 11,755 $ 45 $ 478 $ 11,322 The Company's assets measured at fair value on a recurring basis were as follows: Fair Value Measurements at March 31, 2024, Using Quoted Prices in Significant Significant Balance at March 31, 2024 (In thousands) Assets: Money market funds $ — $ 6,985 — $ 6,985 Insurance contracts* — 62,713 — 62,713 Available-for-sale securities: Mortgage-backed securities — 7,569 — 7,569 U.S. Treasury securities — 3,789 — 3,789 Total assets measured at fair value $ — $ 81,056 $ — $ 81,056 * The insurance contracts invest approximately 57 percent in fixed-income investments, 17 percent in common stock of large-cap companies, 10 percent in target date investments, 8 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 3 percent in cash equivalents, and 1 percent in international investments. Fair Value Measurements at March 31, 2023, Using Quoted Prices in Significant Significant Balance at March 31, 2023 (In thousands) Assets: Money market funds $ — $ 5,447 $ — $ 5,447 Insurance contracts* — 83,460 — 83,460 Available-for-sale securities: Mortgage-backed securities — 7,999 — 7,999 U.S. Treasury securities — 2,980 — 2,980 Total assets measured at fair value $ — $ 99,886 $ — $ 99,886 * The insurance contracts invest approximately 61 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in common stock of mid-cap companies, 7 in target date investments, 6 percent in common stock of small-cap companies, 2 percent in cash equivalents and 1 percent in international investments. Fair Value Measurements at December 31, 2023, Using Quoted Prices in Significant Significant Balance at December 31, 2023 (In thousands) Assets: Money market funds $ — $ 6,409 $ — $ 6,409 Insurance contracts* — 66,283 — 66,283 Available-for-sale securities: Mortgage-backed securities — 7,781 — 7,781 U.S. Treasury securities — 3,541 — 3,541 Total assets measured at fair value $ — $ 84,014 $ — $ 84,014 * The insurance contracts invest approximately 60 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in target date investments, 7 percent in common stock of mid-cap companies, 5 percent in common stock of small-cap companies, 3 percent in cash equivalents, 1 percent in high yield investments and 1 percent in international investments. The Company's money market funds are valued at the net asset value of shares held at the end of the period, based on published market quotations on active markets, or using other known sources including pricing from outside sources. The estimated fair value of the Company's mortgage-backed securities and U.S. Treasury securities are based on comparable market transactions, other observable inputs or other sources, including pricing from outside sources. The estimated fair value of the Company's insurance contracts are based on contractual cash surrender values that are determined primarily by investments in managed separate accounts of the insurer. These amounts approximate fair value. The managed separate accounts are valued based on other observable inputs or corroborated market data. Though the Company believes the methods used to estimate fair value are consistent with those used by other market participants, the use of other methods or assumptions could result in a different estimate of fair value. The Company applies the provisions of the fair value measurement standard to its nonrecurring, non-financial measurements, including long-lived asset impairments. These assets are not measured at fair value on an ongoing basis but are subject to fair value adjustments only in certain circumstances. The Company reviews the carrying value of its long-lived assets, excluding goodwill, whenever events or changes in circumstances indicate that such carrying amounts may not be recoverable. The Company's long-term debt is not measured at fair value on the Consolidated Balance Sheets and the fair value is being provided for disclosure purposes only. The fair value was categorized as Level 2 in the fair value hierarchy and was based on discounted future cash flows using current market interest rates. The estimated fair value of the Company's Level 2 long-term debt was as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Carrying amount $ 2,386,397 $ 2,239,718 $ 2,298,223 Fair value $ 2,098,002 $ 1,974,344 $ 2,046,039 The carrying amounts of the Company's remaining financial instruments included in current assets and current liabilities approximate their fair values .

Debt

Debt	3 Months Ended
Debt	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt	Debt Due to the Knife River separation, Centennial repaid all of its outstanding debt in the second quarter of 2023, which was funded by the Knife River repayment and the Company entering into various new debt instruments. Refer to Note 3 for additional information related to the repayment of debt associated with the Knife River separation. Certain debt instruments of the Company and its subsidiaries contain restrictive and financial covenants and cross-default provisions. In order to borrow under the debt agreements, the Company and its subsidiaries must be in compliance with the applicable covenants and certain other conditions, all of which the Company and its subsidiaries, as applicable, were in compliance with at March 31, 2024. In the event the Company or its subsidiaries do not comply with the applicable covenants and other conditions, alternative sources of funding may need to be pursued. Montana-Dakota's commercial paper program is supported by a revolving credit agreement. While the amount of commercial paper outstanding does not reduce available capacity under the revolving credit agreement, Montana-Dakota does not issue commercial paper in an aggregate amount exceeding the available capacity under the credit agreement. The commercial paper and revolving credit agreement borrowings may vary during the period, largely the result of fluctuations in working capital requirements due to the seasonality of certain operations of Montana-Dakota. Short-term debt Cascade On January 20, 2023, Cascade entered into a $150.0 million term loan agreement with a SOFR-based variable interest rate and a maturity date of January 19, 2024. On December 5, 2023, Cascade paid down $100.0 million of the outstanding balance. On January 19, 2024, Cascade made the final $50.0 million repayment on the $150.0 million term loan agreement. Intermountain On January 20, 2023, Intermountain entered into a $125.0 million term loan agreement with a SOFR-based variable interest rate and a maturity date of January 19, 2024. In March, April, and May 2023, Intermountain paid down $20.0 million, $30.0 million, and $30.0 million, respectively, of the outstanding balance. On January 19, 2024, Intermountain made the final $45.0 million repayment on the $125.0 million term loan agreement. Long-term debt Long-term Debt Outstanding Long-term debt outstanding was as follows: Weighted Average Interest Rate at March 31, 2024 March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Senior Notes due on dates ranging from July 15, 2024 to June 15, 2062 4.46 % $ 1,882,000 $ 1,848,500 $ 1,882,000 Term Loan Agreements due on dates ranging from May 31, 2025 to September 3, 2032 6.48 % 196,300 7,000 196,300 Commercial paper supported by revolving credit agreement 5.72 % 158,800 264,540 144,200 Credit agreements due on dates ranging from October 13, 2027 to November 30, 2027 8.57 % 120,700 89,144 46,100 Medium-Term Notes due on dates ranging from September 15, 2027 to March 16, 2029 7.32 % 35,000 35,000 35,000 Other notes due on dates ranging from May 31, 2028 to November 30, 2038 6.00 % 357 991 980 Less unamortized debt issuance costs 6,760 5,174 6,357 Less discount — 284 — Total long-term debt 2,386,397 2,239,717 2,298,223 Less current maturities 60,700 47,819 61,319 Net long-term debt $ 2,325,697 $ 2,191,898 $ 2,236,904 Schedule of Debt Maturities Long-term debt maturities, which excludes unamortized debt issuance costs and discount, at March 31, 2024, were as follows: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Long-term debt maturities $ 60,700 $ 347,700 $ 140,700 $ 141,400 $ 234,500 $ 1,468,157

Cash flow information

Cash flow information	3 Months Ended
Cash flow information	Mar. 31, 2024
Supplemental Cash Flow Information [Abstract]
Cash flow information	Cash flow information Cash expenditures for interest and income taxes were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Interest, net* $ 21,155 $ 21,362 Income taxes paid (refunded), net** $ (257) $ 7,972 * AFUDC - borrowed was $2.7 million and $2.4 million for the three months ended March 31, 2024 and 2023, respectively. Interest, net also includes interest classified as discontinued operations in 2023. Noncash investing and financing transactions were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Right-of-use assets obtained in exchange for new operating lease liabilities $ 12,735 $ 13,201 $ 46,181 Property, plant and equipment additions in accounts payable $ 32,972 $ 29,564 $ 46,622

Business segment data

Business segment data	3 Months Ended
Business segment data	Mar. 31, 2024
Segment Reporting [Abstract]
Business segment data	Business segment data The Company's reportable segments are those that are based on the Company's method of internal reporting, which generally segregates the strategic business units due to differences in products, services and regulation. The internal reporting of these operating segments is defined based on the reporting and review process used by the Company's chief executive officer. The Company's operations are located within the United States. The electric segment generates, transmits and distributes electricity in Montana, North Dakota, South Dakota and Wyoming. The natural gas distribution segment distributes natural gas in those states, as well as in Idaho, Minnesota, Oregon and Washington. These operations also supply related value-added services. The pipeline segment provides natural gas transportation and underground storage services through a regulated pipeline system primarily in the Rocky Mountain and northern Great Plains regions of the United States. This segment also provides non-regulated energy-related services, including cathodic protection. The construction services segment provides a full spectrum of construction services through its electrical and mechanical and transmission and distribution specialty contracting services across the United States. These specialty contracting services are provided to utilities, manufacturing, transportation, commercial, industrial, institutional, renewable and governmental customers. Its electrical and mechanical contracting services include construction and maintenance of electrical and communication wiring and infrastructure, fire suppression systems, and mechanical piping and services. Its transmission and distribution contracting services include construction and maintenance of overhead and underground electrical, gas and communication infrastructure, as well as manufacturing and supplying transmission and distribution line construction equipment and tools. The Other category includes the activities of Centennial Capital, which, through its subsidiary InterSource Insurance Company, insures various types of risks as a captive insurer for certain of the Company's subsidiaries. The function of the captive insurer is to fund the self-insured layers of the insured Company's general liability, automobile liability, pollution liability and other coverages. Centennial Capital also owns certain real and personal property. In addition, the Other category includes certain assets, liabilities and tax adjustments of the holding company primarily associated with corporate functions, as well as costs associated with certain strategic initiatives. Also included are certain general and administrative costs (reflected in operation and maintenance expense) and interest expense, which were previously allocated to the refining business, Fidelity and Knife River which do not meet the criteria for income (loss) from discontinued operations. Discontinued operations includes Knife River's operations, associated separation costs and interest on debt facilities repaid in connection with the Knife River separation. Discontinued operations also includes the supporting activities of Fidelity other than certain general and administrative costs and interest expense as described above. The information below follows the same accounting policies as described in Note 2 of the Notes to Consolidated Financial Statements in the 2023 Annual Report. Information on the Company's segments was as follows: Three Months Ended March 31, 2024 2023 (In thousands) External operating revenues: Regulated operations: Electric $ 107,727 $ 95,697 Natural gas distribution 459,469 565,597 Pipeline 18,821 12,638 586,017 673,932 Non-regulated operations: Pipeline 2,190 1,833 Construction services 625,602 754,333 Other 16 — 627,808 756,166 Total external operating revenues $ 1,213,825 $ 1,430,098 Intersegment operating revenues: Regulated operations: Electric $ 28 $ 27 Natural gas distribution 56 70 Pipeline 30,275 26,259 30,359 26,356 Non-regulated operations: Pipeline 36 11 Construction services 87 — Other 1,417 1,572 1,540 1,583 Total intersegment operating revenues $ 31,899 $ 27,939 Operating income (loss): Electric $ 22,788 $ 21,091 Natural gas distribution 58,238 58,505 Pipeline 22,650 13,040 Construction services 38,884 35,217 Other (6,613) (9,332) Total operating income $ 135,947 $ 118,521 Income (loss) from continuing operations: Regulated operations: Electric $ 17,869 $ 16,607 Natural gas distribution 40,070 38,928 Pipeline 15,404 8,929 73,343 64,464 Non-regulated operations: Pipeline (346) (458) Construction services 28,214 28,809 Other (313) (8,940) 27,555 19,411 Income from continuing operations 100,898 83,875 Discontinued operations, net of tax — (45,522) Net income $ 100,898 $ 38,353 A reconciliation of reportable segment operating revenues to consolidated operating revenues is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Operating revenues reconciliation: Total reportable segment operating revenues $ 1,244,291 $ 1,456,465 Other revenue 1,433 1,572 Elimination of intersegment operating revenues (31,899) (27,939) Total consolidated operating revenues $ 1,213,825 $ 1,430,098

Employee benefit plans

Employee benefit plans	3 Months Ended
Employee benefit plans	Mar. 31, 2024
Retirement Benefits [Abstract]
Employee benefit plans	Employee benefit plans Pension and other postretirement plans The Company has noncontributory qualified defined benefit pension plans and other postretirement benefit plans for certain eligible employees. Components of net periodic benefit cost (credit) for the Company's pension benefit plans were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Components of net periodic benefit cost (credit): Interest cost $ 3,200 $ 3,380 Expected return on assets (4,028) (4,298) Amortization of net actuarial loss 1,037 773 Net periodic benefit cost (credit) $ 209 $ (145) Components of net periodic benefit credit for the Company's other postretirement benefit plans were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Components of net periodic benefit credit: Service cost $ 126 $ 138 Interest cost 459 489 Expected return on assets (1,329) (1,348) Amortization of prior service credit (330) (330) Amortization of net actuarial gain (72) (168) Net periodic benefit credit, including amount capitalized (1,146) (1,219) Less amount capitalized 22 24 Net periodic benefit credit $ (1,168) $ (1,243) The components of net periodic benefit cost (credit), other than the service cost component, are included in other income on the Consolidated Statements of Income. The service cost component is included in operation and maintenance expense on the Consolidated Statements of Income. Nonqualified defined benefit plans In addition to the qualified defined benefit pension plans reflected in the table at the beginning of this note, the Company also has unfunded, nonqualified defined benefit plans for executive officers and certain key management employees. The Company's net periodic benefit cost for these plans was $733,000 and $746,000 for the three months ended March 31, 2024 and 2023, respectively. The components of net periodic benefit cost for these plans are included in other income on the Consolidated Statements of Income.

Regulatory matters

Regulatory matters	3 Months Ended
Regulatory matters	Mar. 31, 2024
Regulated Operations [Abstract]
Regulatory matters	Regulatory matters The Company regularly reviews the need for electric and natural gas rate changes in each of the jurisdictions in which service is provided. The Company files for rate adjustments to seek recovery of operating costs and capital investments, as well as reasonable returns as allowed by regulators. Certain regulatory proceedings and cases may also contain recurring mechanisms that can have an annual true-up. Examples of these recurring mechanisms include: infrastructure riders, transmission trackers, renewable resource cost adjustment riders, as well as weather normalization and decoupling mechanisms. The following paragraphs summarize the Company's significant open regulatory proceedings and cases by jurisdiction including updates to those reported in the 2023 Annual Report and should be read in conjunction with previous filings. The Company is unable to predict the ultimate outcome of these matters, the timing of final decisions of the various regulators and courts, or the effect on the Company's results of operations, financial position or cash flows. NDPSC On November 1, 2023, Montana-Dakota filed a request with the NDPSC for a natural gas general rate increase of approximately $11.6 million annually or 7.5 percent above current rates. The requested increase is primarily to recover investments in system upgrades and pipeline replacement projects enhancing the reliability, safety and integrity of the natural gas system, as well as increased costs to operate and maintain that system. On December 13, 2023, the NDPSC approved an interim rate increase of approximately $10.1 million annually or 6.5 percent above current rates, subject to refund, for service rendered on and after January 1, 2024. This matter is pending before the NDPSC. SDPUC On August 15, 2023, Montana-Dakota filed a request with the SDPUC for an electric general rate increase of approximately $3.0 million annually or 17.3 percent above current rates. The requested increase is primarily to recover investments in production, transmission and distribution facilities and the associated depreciation, operation and maintenance expense and taxes associated with the increased investment. On January 26, 2024, Montana-Dakota filed a notice of intent to implement interim rates of $2.7 million annually or 15.4 percent above current rates, which reflects the removal of Heskett Unit 4 due to the project delay caused by unforeseen operational setbacks. The interim rates, subject to refund, were effective March 1, 2024. This matter is pending before the SDPUC. On August 15, 2023, Montana-Dakota filed a request with the SDPUC for a natural gas general rate increase of approximately $7.4 million annually or 11.2 percent above current rates. The requested increase is primarily to recover investments in system upgrades and pipeline replacement projects enhancing the reliability, safety and integrity of the natural gas system, as well as increased costs to operate and maintain that system. On January 26, 2024, Montana-Dakota filed a notice of intent to implement interim rates, subject to refund, which were effective March 1, 2024. This matter is pending before the SDPUC. WUTC On March 29, 2024, Cascade filed a request with the WUTC for a multi-year natural gas general rate increase of $43.8 million or 11.6 percent effective March 1, 2025 and $11.7 million or 2.8 percent to be effective March 1, 2026. Multi-year filings are now required by Washington law that went into effect on January 1, 2022. The requested increase is primarily to recover infrastructure investments necessary to provide safe and reliable service and higher operating costs due to inflation. This matter is pending before the WUTC.

Contingencies

Contingencies	3 Months Ended
Contingencies	Mar. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contingencies	Contingencies The Company is party to claims and lawsuits arising out of its business and that of its consolidated subsidiaries, which may include, but are not limited to, matters involving property damage, personal injury, and environmental, contractual, statutory and regulatory obligations. The Company accrues a liability for those contingencies when the incurrence of a loss is probable and the amount can be reasonably estimated. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. The Company does not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated or when the liability is believed to be only reasonably possible or remote. For contingencies where an unfavorable outcome is probable or reasonably possible and which are material, the Company discloses the nature of the contingency and, in some circumstances, an estimate of the possible loss. Accruals are based on the best information available, but in certain situations management is unable to estimate an amount or range of a reasonably possible loss including, but not limited to when: (1) the damages are unsubstantiated or indeterminate, (2) the proceedings are in the early stages, (3) numerous parties are involved, or (4) the matter involves novel or unsettled legal theories. At March 31, 2024 and 2023, and December 31, 2023, the Company accrued liabilities, which have not been discounted, of $22.9 million, $23.4 million and $22.5 million, respectively. At March 31, 2024 and 2023, and December 31, 2023, the Company also recorded corresponding insurance receivables of $80,000, $2.0 million and $202,000, respectively, and regulatory assets of $21.6 million, $20.9 million and $21.6 million, respectively, related to the accrued liabilities. The accruals are for contingencies resulting from litigation and environmental matters. This includes amounts that have been accrued for matters discussed in Environmental matters within this note. The Company will continue to monitor each matter and adjust accruals as might be warranted based on new information and further developments. Management believes that the outcomes with respect to probable and reasonably possible losses in excess of the amounts accrued, net of insurance recoveries, while uncertain, either cannot be estimated or will not have a material effect upon the Company's financial position, results of operations or cash flows. Unless otherwise required by GAAP, legal costs are expensed as they are incurred. Environmental matters The Company is a party to claims for the cleanup of environmental contamination at certain manufactured gas plant sites. There were no material changes to the Company's environmental matters that were previously reported in the 2023 Annual Report. Guarantees Certain subsidiaries of the Company have outstanding guarantees to third parties that guarantee the performance of other subsidiaries of the Company. These guarantees are related to construction contracts, insurance deductibles and loss limits, and certain other guarantees. At March 31, 2024, the fixed maximum amounts guaranteed under these agreements aggregate $329.9 million. Certain of the guarantees also have no fixed maximum amounts specified. At March 31, 2024, the amounts of scheduled expiration of the maximum amounts guaranteed under these agreements aggregate to $53.0 million in 2024; $210.7 million in 2025; $64.9 million in 2026; $1.0 million in 2027; $0.3 million in 2028; and $0 thereafter. There were no amounts outstanding under the previously mentioned guarantees at March 31, 2024. In the event of default under these guarantee obligations, the subsidiary issuing the guarantee for that particular obligation would be required to make payments under its guarantee. The Company and certain subsidiaries have outstanding letters of credit to third parties related to insurance policies and other agreements, some of which are guaranteed by other subsidiaries of the Company. At March 31, 2024, the fixed maximum amounts guaranteed under these letters of credit aggregated $14.3 million, with the scheduled expiration of the maximum amounts guaranteed under these letters aggregate $12.3 million in 2024 and $2.0 million in 2025. There were no amounts outstanding under the previously mentioned letters of credit at March 31, 2024. In the event of default under these letter of credit obligations, the subsidiary guaranteeing the letter of credit would be obligated for reimbursement of payments made under the letter of credit. In addition, Centennial and Everus Construction have issued guarantees to third parties related to the routine purchase of maintenance items, materials and lease obligations for which no fixed maximum amounts have been specified. These guarantees have no scheduled maturity date. In the event a subsidiary of the Company defaults under these obligations, Centennial or Everus Construction would be required to make payments under these guarantees. Any amounts outstanding by subsidiaries of the Company were reflected on the Consolidated Balance Sheet at March 31, 2024. In the normal course of business, Centennial has surety bonds related to construction contracts and reclamation obligations of its subsidiaries. In the event a subsidiary of Centennial does not fulfill a bonded obligation, Centennial would be responsible to the surety bond company for completion of the bonded contract or obligation. A large portion of the surety bonds is expected to expire within the next 12 months; however, Centennial will likely continue to enter into surety bonds for its subsidiaries in the future. At March 31, 2024, approximately $738.1 million of surety bonds were outstanding, which were not reflected on the Consolidated Balance Sheet. Variable interest entities The Company evaluates its arrangements and contracts with other entities to determine if they are VIEs and if so, if the Company is the primary beneficiary. Fuel Contract Coyote Station entered into a coal supply agreement with Coyote Creek that provides for the purchase of coal necessary to supply the coal requirements of the Coyote Station for the period May 2016 through December 2040. Coal purchased under the coal supply agreement is reflected in inventories on the Consolidated Balance Sheets and is recovered from customers as a component of electric fuel and purchased power. The coal supply agreement creates a variable interest in Coyote Creek due to the transfer of all operating and economic risk to the Coyote Station owners, as the agreement is structured so that the price of the coal will cover all costs of operations, as well as future reclamation costs. The Coyote Station owners are also providing a guarantee of the value of the assets of Coyote Creek as they would be required to buy the assets at book value should they terminate the contract prior to the end of the contract term and are providing a guarantee of the value of the equity of Coyote Creek in that they are required to buy the entity at the end of the contract term at equity value. Although the Company has determined that Coyote Creek is a VIE, the Company has concluded that it is not the primary beneficiary of Coyote Creek because the authority to direct the activities of the entity is shared by the four unrelated owners of the Coyote Station, with no primary beneficiary existing. As a result, Coyote Creek is not required to be consolidated in the Company's financial statements. At March 31, 2024, the Company's exposure to loss as a result of the Company's involvement with the VIE, based on the Company's ownership percentage, was $27.1 million.

Subsequent event

Subsequent event	3 Months Ended
Subsequent event	Mar. 31, 2024
Subsequent Events [Abstract]
Subsequent event	Subsequent event On April 1, 2024, WBI Energy Transmission entered into a $60.0 million term loan agreement with an interest rate of 4.52 percent and a maturity date of April 1, 2039. The agreement contains customary covenants and provisions, including a covenant of WBI Energy Transmission not to permit, at any time, the ratio of total debt to total capitalization to be greater than 65 percent. The covenants also include certain restrictions on the sale of certain assets, loans and investments.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended
Pay vs Performance Disclosure - USD ($) $ in Thousands	Mar. 31, 2024	Mar. 31, 2023
Pay vs Performance Disclosure
Net income	$ 100,898	$ 38,353

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
Insider Trading Arrangements	Mar. 31, 2024
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

Basis of presentation (Policies

Basis of presentation (Policies)	3 Months Ended
Basis of presentation (Policies)	Mar. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of presentation	The accompanying consolidated interim financial statements were prepared in accordance with GAAP for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Interim financial statements do not include all disclosures provided in annual financial statements and, accordingly, these financial statements should be read in conjunction with those appearing in the 2023 Annual Report. The information is unaudited but includes all adjustments that are, in the opinion of management, necessary for a fair presentation of the accompanying consolidated interim financial statements and are of a normal recurring nature. Depreciation and amortization expense is reported separately on the Consolidated Statements of Income and therefore is excluded from the other line items within operating expenses.
New accounting standards	The following table provides a brief description of the accounting pronouncements applicable to the Company and the potential impact on its Consolidated Financial Statements and/or disclosures: Standard Description Effective date Impact on financial statements/disclosures Recently adopted accounting standards ASU 2022-06 - Reference Rate Reform: Deferral of Sunset Date In December 2022, the FASB included a sunset provision within ASC 848 based on expectations of when LIBOR would cease being published. At the time ASU 2020-04 was issued, the UK Financial Conduct Authority had established its intent to cease overnight tenors of LIBOR after December 31, 2021. In March 2021, the UK Financial Conduct Authority announced that the intended cessation date of the overnight tenors of LIBOR would be June 30, 2023 which is beyond the current sunset date of ASC 848. The amendments in this Update defer the sunset date of ASC 848 from December 31, 2022 to December 31, 2024, after which entities will no longer be permitted to apply the relief in ASC 848. December 31, 2024 The Company has updated its credit agreements to include language regarding the successor or alternate rate to LIBOR. The Company does not expect the guidance to have a material impact on its results of operations, financial position, cash flows or disclosures. Recently issued accounting standards not yet adopted ASU 2023-05 Business Combinations - Joint Venture Formations - Recognition and Initial Measurement In August 2023, the FASB issued guidance on accounting for contributions made to a joint venture, upon formation, in a joint venture's separate financial statement in order to provide decision-useful information to investors and other allocators of capital (collectively investors) in a joint venture's financial statements and reduce diversity in practice. The new basis of accounting will require that a joint venture, upon formation, will recognize and initially measure its assets and liabilities at fair value (with the exceptions to fair value measurement that are consistent with the business combinations guidance). A joint venture that was formed before January 1, 2025 may elect to apply the guidance retrospectively if it has sufficient information. Effective prospectively for all joint venture formations with a formation date on or after January 1, 2025. The Company is currently evaluating the impact the guidance will have on its interim and annual disclosures for the year ended December 31, 2025. ASU 2023-07 Segment Reporting - Improvements to Reportable Segment Disclosures In November 2023, the FASB issued guidance on improving financial reporting by requiring disclosure of incremental segment information, primarily through enhanced disclosures about significant segment expenses, on an annual and interim basis for all public entities to enable investors to develop more decision-useful financial analyses. Effective for fiscal year December 31, 2024 and interim periods beginning January 1, 2025, with prior periods disclosed in the period of adoption. The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2024 and future interim periods. ASU 2023-09 Income Taxes - Improvements to Income Tax Disclosures an Amendment, December 2023 The FASB issued guidance to address investors requests for more transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information and effectiveness of income tax disclosures. December 31, 2025 The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025. ASU 2024-01 Compensation - Stock Compensation This FASB issued improvements to GAAP through an example to demonstrate application of the scope of paragraph 718-10-15-3 to determine whether profits interest and similar awards should be accounted in Compensation - Stock Compensation. Effective for fiscal year beginning after December 15, 2024. The Company is currently evaluating the impact the guidance will have on its disclosures for the year ended December 31, 2025.
Discontinued operations	As a result of the separation, the historical assets and liabilities for Knife River have been classified as assets and liabilities of discontinued operations and the historical results of operations are shown in discontinued operations, net of tax, other than allocated general corporate overhead costs of the Company, which do not meet the criteria for income (loss) from discontinued operations. The Company’s consolidated financial statements and accompanying notes for prior periods have been restated.
Expected credit loss	The Company's expected credit losses are determined through a review using historical credit loss experience; changes in asset specific characteristics; current conditions; and reasonable and supportable future forecasts, among other specific account data, and is performed at least quarterly. The Company develops and documents its methodology to determine its allowance for expected credit losses at each of its reportable business segments. Risk characteristics used by the business segments may include customer mix, knowledge of customers and general economic conditions of the various local economies, among others. Specific account balances are written off when management determines the amounts to be uncollectible.
Inventories and natural gas in storage	Natural gas in storage for the Company's regulated operations is generally valued at lower of cost or market using the last-in, first-out method or lower of cost or net realizable value using the average cost or first-in, first-out method. The majority of all other inventories are valued at the lower of cost or net realizable value using the average cost method.
Earnings per share	Basic earnings per share is computed by dividing net income by the weighted average number of shares of common stock outstanding during the applicable period. Diluted earnings per share is computed by dividing net income by the total of the weighted average number of shares of common stock outstanding during the applicable period, plus the effect of non-vested performance share awards and restricted stock units. Common stock outstanding includes issued shares less shares held in treasury.
Revenue from contracts with customers	Revenue is recognized when a performance obligation is satisfied by transferring control over a product or service to a customer. Revenue is measured based on consideration specified in a contract with a customer and excludes any sales incentives and amounts collected on behalf of third parties. The Company is considered an agent for certain taxes collected from customers. As such, the Company presents revenues net of these taxes at the time of sale to be remitted to governmental authorities, including sales and use taxes. As part of the adoption of ASC 606 - Revenue from Contracts with Customers , the Company elected the practical expedient to recognize the incremental costs of obtaining a contract as an expense when incurred if the amortization period of the asset that the Company otherwise would have recognized is 12 months or less. The Company recognizes revenue from the sale of emissions allowances allocated under the environmental programs in certain states. The Company has the right to payment when the allowances are sold at auction. Revenue is recognized on a point in time basis within the quarter that the auction is held. The revenues associated with the sale of these allowances are deferred as a component of the respective jurisdiction’s regulatory asset or liability for environmental compliance. For more information on the Company’s regulatory assets and liabilities, see Note 10.
Environmental allowances and obligations	Environmental allowances and obligations Beginning in 2023, the Company's natural gas distribution segment acquires environmental allowances as part of its requirement to comply with environmental regulations in certain states. Allowances are allocated by the respective states to the Company at no cost and additional allowances are required to be purchased as needed based on the requirements in the respective states. The segment records purchased and allocated environmental allowances at weighted average cost under the inventory method of accounting. Environmental allowances are included in prepayments and other current assets and noncurrent assets - other on the Consolidated Balance Sheets. Environmental compliance obligations, which are based on GHG emissions, are measured at the carrying value of environmental allowances held plus the estimated value of additional allowances necessary to satisfy the compliance obligation. Environmental compliance obligations are included in current liabilities - other accrued liabilities and noncurrent liabilities - other on the Consolidated Balance Sheets. The Company recognizes revenue from the sale of emissions allowances allocated under the environmental programs when the allowances are sold at auction. The revenues associated with the sale of these allowances are deferred as a component of the respective jurisdiction’s regulatory liability for environmental compliance. As environmental allowances are surrendered, the segment reduces the associated environmental compliance assets and liabilities from the Consolidated Balance Sheets. The expenses and revenues associated with the Company’s environmental allowances and obligations are deferred as regulatory assets and liabilities. For more information on the Company’s regulatory assets and liabilities, see Note 10.
Fair value measurements	The Company measures its investments in certain fixed-income and equity securities at fair value with changes in fair value recognized in income.
Investments	The Company did not elect the fair value option, which records gains and losses in income, for its available-for-sale securities, which include mortgage-backed securities and U.S. Treasury securities. These available-for-sale securities are recorded at fair value and are classified as investments on the Consolidated Balance Sheets.
Business segment data	The Company's reportable segments are those that are based on the Company's method of internal reporting, which generally segregates the strategic business units due to differences in products, services and regulation. The internal reporting of these operating segments is defined based on the reporting and review process used by the Company's chief executive officer.
Contingencies	The Company is party to claims and lawsuits arising out of its business and that of its consolidated subsidiaries, which may include, but are not limited to, matters involving property damage, personal injury, and environmental, contractual, statutory and regulatory obligations. The Company accrues a liability for those contingencies when the incurrence of a loss is probable and the amount can be reasonably estimated. If a range of amounts can be reasonably estimated and no amount within the range is a better estimate than any other amount, then the minimum of the range is accrued. The Company does not accrue liabilities when the likelihood that the liability has been incurred is probable but the amount cannot be reasonably estimated or when the liability is believed to be only reasonably possible or remote. For contingencies where an unfavorable outcome is probable or reasonably possible and which are material, the Company discloses the nature of the contingency and, in some circumstances, an estimate of the possible loss. Accruals are based on the best information available, but in certain situations management is unable to estimate an amount or range of a reasonably possible loss including, but not limited to when: (1) the damages are unsubstantiated or indeterminate, (2) the proceedings are in the early stages, (3) numerous parties are involved, or (4) the matter involves novel or unsettled legal theories.
Variable interest entity	The Company evaluates its arrangements and contracts with other entities to determine if they are VIEs and if so, if the Company is the primary beneficiary.

Discontinued operations (Tables

Discontinued operations (Tables)	3 Months Ended
Discontinued operations (Tables)	Mar. 31, 2024
Discontinued Operations and Disposal Groups [Abstract]
Schedule of discontinued operations, including balance sheet and income statement	The carrying amounts of the major classes of assets and liabilities of discontinued operations included in the Company’s Consolidated Balance Sheet at March 31, 2023 were as follows: March 31, 2023 Assets (In Thousands) Current assets: Cash and cash equivalents $ 7,218 Receivables, net 205,564 Inventories 373,215 Prepayments and other current assets 34,899 Total current assets of discontinued operations 620,896 Noncurrent assets: Net property, plant and equipment 1,317,368 Goodwill 274,540 Other intangible assets, net 12,763 Investments 35,542 Operating lease right-of-use assets 43,995 Other 3,403 Total noncurrent assets of discontinued operations 1,687,611 Total assets of discontinued operations $ 2,308,507 Liabilities Current liabilities: Short-term borrowings $ 208,000 Long-term debt due within one year 30,211 Accounts payable 118,175 Taxes payable (1,402) Accrued compensation 14,010 Operating lease liabilities due within one year 12,981 Other accrued liabilities 66,740 Total current liabilities of discontinued operations 448,715 Noncurrent liabilities: Long-term debt 577,138 Deferred income taxes 175,062 Asset retirement obligations 33,462 Operating lease liabilities 31,014 Other 80,409 Total noncurrent liabilities of discontinued operations 897,085 Total liabilities of discontinued operations $ 1,345,800 The reconciliation of the major classes of income and expense constituting pretax loss from discontinued operations to the after-tax loss from discontinued operations on the Consolidated Statements of Income were as follows: Three Months Ended March 31, 2023 (In thousands) Operating revenues $ 307,239 Operating expenses 351,274 Operating loss (44,035) Other income 493 Interest expense 14,067 Loss from discontinued operations before income taxes (57,609) Income taxes (12,087) Discontinued operations, net of tax $ (45,522)

Receivables and allowance for_2

Receivables and allowance for expected credit losses (Tables)	3 Months Ended
	Mar. 31, 2024
Credit Loss [Abstract]
Accounts Receivable, Allowance for Credit Loss	Details of the Company's expected credit losses were as follows: Electric Natural gas Pipeline Construction Total (In thousands) At December 31, 2023 $ 414 $ 1,189 $ — $ 7,967 $ 9,570 Current expected credit loss provision 782 1,916 — (411) 2,287 Less write-offs charged against the allowance 659 1,455 — 48 2,162 Credit loss recoveries collected 147 314 — — 461 At March 31, 2024 $ 684 $ 1,964 $ — $ 7,508 $ 10,156 Electric Natural gas Pipeline Construction Total (In thousands) At December 31, 2022 $ 375 $ 1,615 $ 2 $ 2,162 $ 4,154 Current expected credit loss provision 615 2,324 — 826 3,765 Less write-offs charged against the allowance 667 1,225 — 51 1,943 Credit loss recoveries collected 145 229 — 1 375 At March 31, 2023 $ 468 $ 2,943 $ 2 $ 2,938 $ 6,351

Inventories and natural gas i_2

Inventories and natural gas in storage (Tables)	3 Months Ended
Inventories and natural gas in storage (Tables)	Mar. 31, 2024
Inventory Disclosure [Abstract]
Inventories	Inventories on the Consolidated Balance Sheets were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Merchandise for resale 38,280 29,934 34,955 Natural gas in storage (current) 9,309 8,662 39,377 Materials and supplies $ 3,636 $ 7,064 $ 5,460 Other 6,204 6,959 7,600 Total $ 57,429 $ 52,619 $ 87,392

Earnings per share (Tables)

Earnings per share (Tables)	3 Months Ended
Earnings per share (Tables)	Mar. 31, 2024
Earnings Per Share [Abstract]
Weighted average common shares outstanding	A reconciliation of the weighted average common shares outstanding used in the basic and diluted earnings per share calculations follows: Three Months Ended March 31, 2024 2023 (In thousands, except per share amounts) Weighted average common shares outstanding - basic 203,779 203,624 Effect of dilutive performance share awards and restricted stock units 408 286 Weighted average common shares outstanding - diluted 204,187 203,910 Earnings per share - basic: Income from continuing operations $ .50 $ .41 Discontinued operations, net of tax — (.22) Earnings per share - basic $ .50 $ .19 Earnings per share - diluted: Income from continuing operations $ .49 $ .41 Discontinued operations, net of tax — (.22) Earnings per share - diluted $ .49 $ .19 Shares excluded from the calculation of diluted earnings per share — — Dividends declared per common share 0.1250 $ .2225

Revenue from contracts with c_2

Revenue from contracts with customers (Tables)	3 Months Ended
Revenue from contracts with customers (Tables)	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Disaggregation of revenue	In the following tables, revenue is disaggregated by the type of customer or service provided. The Company believes this level of disaggregation best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. The table also includes a reconciliation of the disaggregated revenue by reportable segments. For more information on the Company's business segments, see Note 15. Three Months Ended March 31, 2024 Electric Natural gas Pipeline Construction Other Total (In thousands) Residential utility sales $ 39,222 $ 263,103 $ — $ — $ — $ 302,325 Commercial utility sales 41,515 162,130 — — — 203,645 Industrial utility sales 11,349 14,579 — — — 25,928 Other utility sales 1,936 — — — — 1,936 Natural gas transportation — 14,591 43,637 — — 58,228 Natural gas storage — — 5,382 — — 5,382 Electrical & mechanical specialty contracting — — — 439,378 — 439,378 Transmission & distribution specialty contracting — — — 176,860 — 176,860 Other 15,630 3,201 2,256 46 1,433 22,566 Intersegment eliminations (28) (56) (30,311) (87) (1,417) (31,899) Revenues from contracts with customers 109,624 457,548 20,964 616,197 16 1,204,349 Other revenues (1,897) 1,921 47 9,405 — 9,476 Total external operating revenues $ 107,727 $ 459,469 $ 21,011 $ 625,602 $ 16 $ 1,213,825 Three Months Ended March 31, 2023 Electric Natural gas Pipeline Construction Other Total (In thousands) Residential utility sales $ 37,825 $ 327,651 $ — $ — $ — $ 365,476 Commercial utility sales 36,347 204,927 — — — 241,274 Industrial utility sales 10,763 16,838 — — — 27,601 Other utility sales 1,774 — — — — 1,774 Natural gas transportation — 13,504 34,983 — — 48,487 Natural gas storage — — 3,861 — — 3,861 Electrical & mechanical specialty contracting — — — 590,263 — 590,263 Transmission & distribution specialty contracting — — — 152,022 — 152,022 Other 11,878 4,721 1,859 33 1,572 20,063 Intersegment eliminations (27) (70) (26,270) — (1,572) (27,939) Revenues from contracts with customers 98,560 567,571 14,433 742,318 — 1,422,882 Other revenues (2,863) (1,974) 38 12,015 — 7,216 Total external operating revenues $ 95,697 $ 565,597 $ 14,471 $ 754,333 $ — $ 1,430,098
Contract balances	The changes in contract assets and liabilities were as follows: March 31, 2024 December 31, 2023 Change Location on Consolidated Balance Sheets (In thousands) Contract assets $ 165,924 $ 158,861 $ 7,063 Receivables, net Contract liabilities - current (187,741) (202,144) 14,403 Accounts payable Contract liabilities - noncurrent (2,161) (291) (1,870) Noncurrent liabilities - other Net contract liabilities $ (23,978) $ (43,574) $ 19,596

Regulatory assets and liabili_2

Regulatory assets and liabilities (Tables)	3 Months Ended
Regulatory assets and liabilities (Tables)	Mar. 31, 2024
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Assets	The following table summarizes the individual components of unamortized regulatory assets and liabilities: Estimated Recovery or Refund Period as of March 31, 2024 * March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Regulatory assets: Current: Natural gas costs recoverable through rate adjustments Up to 1 year $ 110,481 $ 198,166 $ 98,844 Electric fuel and purchased power deferral Up to 1 year 17,061 3,279 33,918 Conservation programs Up to 1 year 13,735 8,599 14,425 Environmental compliance programs Up to 1 year 7,443 1,191 5,525 Cost recovery mechanisms Up to 1 year 6,454 3,954 9,153 Other Up to 1 year 3,440 1,129 10,627 158,614 216,318 172,492 Noncurrent: Pension and postretirement benefits 142,511 143,349 142,511 Cost recovery mechanisms Up to 25 years 84,546 65,732 85,944 Environmental compliance programs - 50,372 21,942 66,806 Plant costs/asset retirement obligations Over plant lives 45,702 44,131 46,009 Natural gas costs recoverable through rate adjustments Up to 2 years 25,915 — 55,493 Manufactured gas plant site remediation - 25,851 26,605 26,127 Taxes recoverable from customers Over plant lives 12,331 12,198 12,249 Electric fuel and purchased power deferral Up to 2 years 15,612 — — Long-term debt refinancing costs Up to 36 years 2,453 3,041 2,600 Plant to be retired - 294 21,072 772 Other Up to 15 years 8,846 11,430 8,588 414,433 349,500 447,099 Total regulatory assets $ 573,047 $ 565,818 $ 619,591 Regulatory liabilities: Current: Natural gas costs refundable through rate adjustments Up to 1 year $ 54,282 $ 6,331 $ 43,161 Provision for rate refund Up to 1 year 6,517 1,115 6,866 Cost recovery mechanisms Up to 1 year 5,642 2,926 6,284 Conservation programs Up to 1 year 3,576 3,834 2,130 Margin sharing Up to 1 year 2,869 — 5,243 Taxes refundable to customers Up to 1 year 1,991 1,513 2,149 Refundable fuel and electric costs Up to 1 year 1,122 1,179 263 Electric fuel and purchased power deferral Up to 1 year 746 9,630 — Other Up to 1 year 13,370 17,867 4,665 90,115 44,395 70,761 Noncurrent: Plant removal and decommissioning costs Over plant lives 220,519 214,467 220,147 Taxes refundable to customers Over plant lives 190,850 200,879 193,578 Environmental compliance programs - 63,746 — 61,941 Cost recovery mechanisms Up to 18 years 24,269 16,313 21,791 Accumulated deferred investment tax credit Over plant lives 16,129 13,996 15,740 Pension and postretirement benefits 6,044 7,376 6,044 Other Up to 14 years 1,927 1,638 1,809 523,484 454,669 521,050 Total regulatory liabilities $ 613,599 $ 499,064 $ 591,811 Net regulatory position $ (40,552) $ 66,754 $ 27,780 * Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers. ** Recovered as expense is incurred or cash contributions are made.
Regulatory Liabilities	The following table summarizes the individual components of unamortized regulatory assets and liabilities: Estimated Recovery or Refund Period as of March 31, 2024 * March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Regulatory assets: Current: Natural gas costs recoverable through rate adjustments Up to 1 year $ 110,481 $ 198,166 $ 98,844 Electric fuel and purchased power deferral Up to 1 year 17,061 3,279 33,918 Conservation programs Up to 1 year 13,735 8,599 14,425 Environmental compliance programs Up to 1 year 7,443 1,191 5,525 Cost recovery mechanisms Up to 1 year 6,454 3,954 9,153 Other Up to 1 year 3,440 1,129 10,627 158,614 216,318 172,492 Noncurrent: Pension and postretirement benefits 142,511 143,349 142,511 Cost recovery mechanisms Up to 25 years 84,546 65,732 85,944 Environmental compliance programs - 50,372 21,942 66,806 Plant costs/asset retirement obligations Over plant lives 45,702 44,131 46,009 Natural gas costs recoverable through rate adjustments Up to 2 years 25,915 — 55,493 Manufactured gas plant site remediation - 25,851 26,605 26,127 Taxes recoverable from customers Over plant lives 12,331 12,198 12,249 Electric fuel and purchased power deferral Up to 2 years 15,612 — — Long-term debt refinancing costs Up to 36 years 2,453 3,041 2,600 Plant to be retired - 294 21,072 772 Other Up to 15 years 8,846 11,430 8,588 414,433 349,500 447,099 Total regulatory assets $ 573,047 $ 565,818 $ 619,591 Regulatory liabilities: Current: Natural gas costs refundable through rate adjustments Up to 1 year $ 54,282 $ 6,331 $ 43,161 Provision for rate refund Up to 1 year 6,517 1,115 6,866 Cost recovery mechanisms Up to 1 year 5,642 2,926 6,284 Conservation programs Up to 1 year 3,576 3,834 2,130 Margin sharing Up to 1 year 2,869 — 5,243 Taxes refundable to customers Up to 1 year 1,991 1,513 2,149 Refundable fuel and electric costs Up to 1 year 1,122 1,179 263 Electric fuel and purchased power deferral Up to 1 year 746 9,630 — Other Up to 1 year 13,370 17,867 4,665 90,115 44,395 70,761 Noncurrent: Plant removal and decommissioning costs Over plant lives 220,519 214,467 220,147 Taxes refundable to customers Over plant lives 190,850 200,879 193,578 Environmental compliance programs - 63,746 — 61,941 Cost recovery mechanisms Up to 18 years 24,269 16,313 21,791 Accumulated deferred investment tax credit Over plant lives 16,129 13,996 15,740 Pension and postretirement benefits 6,044 7,376 6,044 Other Up to 14 years 1,927 1,638 1,809 523,484 454,669 521,050 Total regulatory liabilities $ 613,599 $ 499,064 $ 591,811 Net regulatory position $ (40,552) $ 66,754 $ 27,780 * Estimated recovery or refund period for amounts currently being recovered or refunded in rates to customers. ** Recovered as expense is incurred or cash contributions are made.

Fair value measurements (Tables

Fair value measurements (Tables)	3 Months Ended
Fair value measurements (Tables)	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Available-for-sale securities	Details of available-for-sale securities were as follows: March 31, 2024 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,072 $ 4 $ 507 $ 7,569 U.S. Treasury securities 3,756 35 2 3,789 Total $ 11,828 $ 39 $ 509 $ 11,358 March 31, 2023 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,557 $ 3 $ 561 $ 7,999 U.S. Treasury securities 3,023 8 51 2,980 Total $ 11,580 $ 11 $ 612 $ 10,979 December 31, 2023 Cost Gross Gross Fair Value (In thousands) Mortgage-backed securities $ 8,234 $ 17 $ 470 $ 7,781 U.S. Treasury securities 3,521 28 8 3,541 Total $ 11,755 $ 45 $ 478 $ 11,322
Assets and liabilities measured at fair value on a recurring basis	The Company's assets measured at fair value on a recurring basis were as follows: Fair Value Measurements at March 31, 2024, Using Quoted Prices in Significant Significant Balance at March 31, 2024 (In thousands) Assets: Money market funds $ — $ 6,985 — $ 6,985 Insurance contracts* — 62,713 — 62,713 Available-for-sale securities: Mortgage-backed securities — 7,569 — 7,569 U.S. Treasury securities — 3,789 — 3,789 Total assets measured at fair value $ — $ 81,056 $ — $ 81,056 * The insurance contracts invest approximately 57 percent in fixed-income investments, 17 percent in common stock of large-cap companies, 10 percent in target date investments, 8 percent in common stock of mid-cap companies, 4 percent in common stock of small-cap companies, 3 percent in cash equivalents, and 1 percent in international investments. Fair Value Measurements at March 31, 2023, Using Quoted Prices in Significant Significant Balance at March 31, 2023 (In thousands) Assets: Money market funds $ — $ 5,447 $ — $ 5,447 Insurance contracts* — 83,460 — 83,460 Available-for-sale securities: Mortgage-backed securities — 7,999 — 7,999 U.S. Treasury securities — 2,980 — 2,980 Total assets measured at fair value $ — $ 99,886 $ — $ 99,886 * The insurance contracts invest approximately 61 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in common stock of mid-cap companies, 7 in target date investments, 6 percent in common stock of small-cap companies, 2 percent in cash equivalents and 1 percent in international investments. Fair Value Measurements at December 31, 2023, Using Quoted Prices in Significant Significant Balance at December 31, 2023 (In thousands) Assets: Money market funds $ — $ 6,409 $ — $ 6,409 Insurance contracts* — 66,283 — 66,283 Available-for-sale securities: Mortgage-backed securities — 7,781 — 7,781 U.S. Treasury securities — 3,541 — 3,541 Total assets measured at fair value $ — $ 84,014 $ — $ 84,014 * The insurance contracts invest approximately 60 percent in fixed-income investments, 15 percent in common stock of large-cap companies, 8 percent in target date investments, 7 percent in common stock of mid-cap companies, 5 percent in common stock of small-cap companies, 3 percent in cash equivalents, 1 percent in high yield investments and 1 percent in international investments.
Fair value of long term debt outstanding	The estimated fair value of the Company's Level 2 long-term debt was as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Carrying amount $ 2,386,397 $ 2,239,718 $ 2,298,223 Fair value $ 2,098,002 $ 1,974,344 $ 2,046,039

Debt (Tables)

Debt (Tables)	3 Months Ended
Debt (Tables)	Mar. 31, 2024
Debt Disclosure [Abstract]
Long-term debt outstanding	Long-term debt outstanding was as follows: Weighted Average Interest Rate at March 31, 2024 March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Senior Notes due on dates ranging from July 15, 2024 to June 15, 2062 4.46 % $ 1,882,000 $ 1,848,500 $ 1,882,000 Term Loan Agreements due on dates ranging from May 31, 2025 to September 3, 2032 6.48 % 196,300 7,000 196,300 Commercial paper supported by revolving credit agreement 5.72 % 158,800 264,540 144,200 Credit agreements due on dates ranging from October 13, 2027 to November 30, 2027 8.57 % 120,700 89,144 46,100 Medium-Term Notes due on dates ranging from September 15, 2027 to March 16, 2029 7.32 % 35,000 35,000 35,000 Other notes due on dates ranging from May 31, 2028 to November 30, 2038 6.00 % 357 991 980 Less unamortized debt issuance costs 6,760 5,174 6,357 Less discount — 284 — Total long-term debt 2,386,397 2,239,717 2,298,223 Less current maturities 60,700 47,819 61,319 Net long-term debt $ 2,325,697 $ 2,191,898 $ 2,236,904
Schedule of debt maturities	Long-term debt maturities, which excludes unamortized debt issuance costs and discount, at March 31, 2024, were as follows: Remainder of 2024 2025 2026 2027 2028 Thereafter (In thousands) Long-term debt maturities $ 60,700 $ 347,700 $ 140,700 $ 141,400 $ 234,500 $ 1,468,157

Cash flow information (Tables)

Cash flow information (Tables)	3 Months Ended
Cash flow information (Tables)	Mar. 31, 2024
Supplemental Cash Flow Information [Abstract]
Cash expenditures for interest and income taxes and noncash investing and financing transactions	Cash expenditures for interest and income taxes were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Interest, net* $ 21,155 $ 21,362 Income taxes paid (refunded), net** $ (257) $ 7,972 * AFUDC - borrowed was $2.7 million and $2.4 million for the three months ended March 31, 2024 and 2023, respectively. Interest, net also includes interest classified as discontinued operations in 2023. Noncash investing and financing transactions were as follows: March 31, 2024 March 31, 2023 December 31, 2023 (In thousands) Right-of-use assets obtained in exchange for new operating lease liabilities $ 12,735 $ 13,201 $ 46,181 Property, plant and equipment additions in accounts payable $ 32,972 $ 29,564 $ 46,622

Business segment data (Tables)

Business segment data (Tables)	3 Months Ended
Business segment data (Tables)	Mar. 31, 2024
Segment Reporting [Abstract]
Information on the Company's businesses	Information on the Company's segments was as follows: Three Months Ended March 31, 2024 2023 (In thousands) External operating revenues: Regulated operations: Electric $ 107,727 $ 95,697 Natural gas distribution 459,469 565,597 Pipeline 18,821 12,638 586,017 673,932 Non-regulated operations: Pipeline 2,190 1,833 Construction services 625,602 754,333 Other 16 — 627,808 756,166 Total external operating revenues $ 1,213,825 $ 1,430,098 Intersegment operating revenues: Regulated operations: Electric $ 28 $ 27 Natural gas distribution 56 70 Pipeline 30,275 26,259 30,359 26,356 Non-regulated operations: Pipeline 36 11 Construction services 87 — Other 1,417 1,572 1,540 1,583 Total intersegment operating revenues $ 31,899 $ 27,939 Operating income (loss): Electric $ 22,788 $ 21,091 Natural gas distribution 58,238 58,505 Pipeline 22,650 13,040 Construction services 38,884 35,217 Other (6,613) (9,332) Total operating income $ 135,947 $ 118,521 Income (loss) from continuing operations: Regulated operations: Electric $ 17,869 $ 16,607 Natural gas distribution 40,070 38,928 Pipeline 15,404 8,929 73,343 64,464 Non-regulated operations: Pipeline (346) (458) Construction services 28,214 28,809 Other (313) (8,940) 27,555 19,411 Income from continuing operations 100,898 83,875 Discontinued operations, net of tax — (45,522) Net income $ 100,898 $ 38,353
Reconciliation of Revenue from Segments to Consolidated	A reconciliation of reportable segment operating revenues to consolidated operating revenues is as follows: Three Months Ended March 31, 2024 2023 (In thousands) Operating revenues reconciliation: Total reportable segment operating revenues $ 1,244,291 $ 1,456,465 Other revenue 1,433 1,572 Elimination of intersegment operating revenues (31,899) (27,939) Total consolidated operating revenues $ 1,213,825 $ 1,430,098

Employee benefit plans (Tables)

Employee benefit plans (Tables)	3 Months Ended
Employee benefit plans (Tables)	Mar. 31, 2024
Retirement Benefits [Abstract]
Schedule of net benefit costs	Components of net periodic benefit cost (credit) for the Company's pension benefit plans were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Components of net periodic benefit cost (credit): Interest cost $ 3,200 $ 3,380 Expected return on assets (4,028) (4,298) Amortization of net actuarial loss 1,037 773 Net periodic benefit cost (credit) $ 209 $ (145) Components of net periodic benefit credit for the Company's other postretirement benefit plans were as follows: Three Months Ended March 31, 2024 2023 (In thousands) Components of net periodic benefit credit: Service cost $ 126 $ 138 Interest cost 459 489 Expected return on assets (1,329) (1,348) Amortization of prior service credit (330) (330) Amortization of net actuarial gain (72) (168) Net periodic benefit credit, including amount capitalized (1,146) (1,219) Less amount capitalized 22 24 Net periodic benefit credit $ (1,168) $ (1,243)

Basis of presentation (Details)

Basis of presentation (Details) - Discontinued Operations, Disposed of by Means Other than Sale, Spinoff - Knife River Corporation shares in Millions	May 31, 2023 shares
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pro rata distribution of shares, percentage	0.90
Stock split, conversion ratio	4
Retained ownership percentage	0.10
Number of retained shares (in shares)	5.7

Discontinued operations - Narra

Discontinued operations - Narrative (Details)			3 Months Ended
Discontinued operations - Narrative (Details)	May 31, 2023 shares	Apr. 25, 2023 USD ($)	Mar. 31, 2024 USD ($) shares	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt			$ 2,386,397,000	$ 2,239,717,000	$ 2,298,223,000
Repayment of long-term debt			$ 623,000	169,823,000
Treasury stock retired (in shares) \| shares			538,921
Separation related costs				$ 4,300,000
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| Knife River Corporation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Pro rata distribution of shares, percentage	0.90
Stock split, conversion ratio	4
Retained ownership percentage	0.10
Number of retained shares (in shares) \| shares	5,700,000
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| Knife River Corporation \| Cash Received, TSA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operation, amount of continuing cash flows after disposal			$ 1,000,000
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| Knife River Corporation \| Cash Paid, TSA
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Discontinued operation, amount of continuing cash flows after disposal			$ 78,200
Knife River Corporation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Repayment of long-term debt		$ 825,000,000
Knife River Corporation \| Revolving Credit Facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Line of credit facility, maximum borrowing capacity		350,000,000
Knife River Corporation \| Term Loan Agreement
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Debt instrument, face amount		275,000,000
Senior Notes \| Knife River Corporation
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Long-term debt		$ 425,000,000

Discontinued operations - Sched

Discontinued operations - Schedule of Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Sep. 30, 2022
Current assets:
Cash and cash equivalents			$ 7,200
Noncurrent assets:
Total noncurrent assets of discontinued operations	$ 0	$ 0	1,687,611
Current liabilities:
Total current liabilities of discontinued operations	0	0	448,715
Noncurrent liabilities:
Total noncurrent liabilities of discontinued operations	$ 0	$ 0	$ 897,085
Knife River Corporation \| Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Current assets:
Cash and cash equivalents				$ 7,218
Receivables, net				205,564
Inventories				373,215
Prepayments and other current assets				34,899
Total current assets of discontinued operations				620,896
Noncurrent assets:
Net property, plant and equipment				1,317,368
Goodwill				274,540
Other intangible assets, net				12,763
Investments				35,542
Operating lease right-of-use assets				43,995
Other				3,403
Total noncurrent assets of discontinued operations				1,687,611
Total assets of discontinued operations				2,308,507
Current liabilities:
Short-term borrowings				208,000
Long-term debt due within one year				30,211
Accounts payable				118,175
Taxes payable				(1,402)
Accrued compensation				14,010
Operating lease liabilities due within one year				12,981
Other accrued liabilities				66,740
Total current liabilities of discontinued operations				448,715
Noncurrent liabilities:
Long-term debt				577,138
Deferred income taxes				175,062
Asset retirement obligations				33,462
Operating lease liabilities				31,014
Other				80,409
Total noncurrent liabilities of discontinued operations				897,085
Total liabilities of discontinued operations				$ 1,345,800

Discontinued operations - Sch_2

Discontinued operations - Schedule of Income and Expense Constituting Pretax Income (Loss) From Discontinued Operations (Details) - Knife River Corporation - Discontinued Operations, Disposed of by Means Other than Sale, Spinoff $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Operating revenues	$ 307,239
Operating expenses	351,274
Operating loss	(44,035)
Other income	493
Interest expense	14,067
Loss from discontinued operations before income taxes	(57,609)
Income taxes	(12,087)
Discontinued operations, net of tax	$ (45,522)

Receivables and allowance for_3

Receivables and allowance for expected credit losses - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Credit Loss [Abstract]
Accounts receivable, noncurrent, 90 days or more past due, still accruing	$ 70.2	$ 45.7	$ 39.8

Receivables and allowance for_4

Receivables and allowance for expected credit losses - Accounts Receivable, Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Current expected credit loss provision	$ 2,287	$ 3,765
Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	9,570	4,154
Current expected credit loss provision	2,287	3,765
Less write-offs charged against the allowance	2,162	1,943
Credit loss recoveries collected	461	375
Ending balance	10,156	6,351
Electric \| Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	414	375
Current expected credit loss provision	782	615
Less write-offs charged against the allowance	659	667
Credit loss recoveries collected	147	145
Ending balance	684	468
Natural gas distribution \| Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,189	1,615
Current expected credit loss provision	1,916	2,324
Less write-offs charged against the allowance	1,455	1,225
Credit loss recoveries collected	314	229
Ending balance	1,964	2,943
Pipeline \| Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	0	2
Current expected credit loss provision	0	0
Less write-offs charged against the allowance	0	0
Credit loss recoveries collected	0	0
Ending balance	0	2
Construction services \| Trade Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	7,967	2,162
Current expected credit loss provision	(411)	826
Less write-offs charged against the allowance	48	51
Credit loss recoveries collected	0	1
Ending balance	$ 7,508	$ 2,938

Inventories and natural gas i_3

Inventories and natural gas in storage (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Inventory Disclosure [Abstract]
Merchandise for resale	$ 38,280	$ 34,955	$ 29,934
Natural gas in storage (current)	9,309	39,377	8,662
Materials and supplies	3,636	5,460	7,064
Other	6,204	7,600	6,959
Total	57,429	87,392	52,619
Natural gas in storage noncurrent	$ 50,100	$ 48,500	$ 47,400

Earnings per share - Schedule o

Earnings per share - Schedule of Weighted Average Number of Shares (Details) - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Earnings Per Share [Abstract]
Weighted average common shares outstanding - basic (in shares)	203,779	203,624
Effect of dilutive performance share awards and restricted stock units (in shares)	408	286
Weighted average common shares outstanding - diluted (in shares)	204,187	203,910
Earnings per share - basic:
Income from continuing operations (in usd per share)	$ 0.50	$ 0.41
Discontinued operations, net of tax (in usd per share)	0	(0.22)
Earnings per share - basic (in usd per share)	0.50	0.19
Earnings per share - diluted:
Income from continuing operations (in usd per share)	0.49	0.41
Discontinued operations, net of tax (in usd per share)	0	(0.22)
Earnings per share - diluted (in usd per share)	$ 0.49	$ 0.19
Shares excluded from the calculation of diluted earnings per share (in shares)	0	0
Dividends declared per common share (in usd per share)	$ 0.1250	$ 0.2225

Revenue from contracts with c_3

Revenue from contracts with customers - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Construction contractor, contract cost, subject to uncertainty, amount	$ 31
Contract with customer, liability, revenue recognized	97.6	$ 134.6
Amounts from performance obligations satisfied in prior periods	33.4	$ 17.7
Remaining performance obligation, amount	2,800
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 1,800
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 412.8
Revenue, remaining performance obligation, expected timing of satisfaction, period	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, amount	$ 530.6
Revenue, remaining performance obligation, expected timing of satisfaction, period
Construction services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with customer, term (less than)	2 years
Pipeline
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract with customer, term (less than)	12 months
Pipeline \| Firm Transportation Contract
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract weighted average remaining duration (less than)	5 years
Pipeline \| Firm Storage Contract
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Contract weighted average remaining duration (less than)	2 years

Revenue from contracts with c_4

Revenue from contracts with customers - Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 1,204,349	$ 1,422,882
Other revenues	9,476	7,216
Total external operating revenues	1,213,825	1,430,098
Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(31,899)	(27,939)
Total external operating revenues	(31,899)	(27,939)
Operating Segments
Disaggregation of Revenue [Line Items]
Total external operating revenues	1,244,291	1,456,465
Natural gas transportation
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	58,228	48,487
Natural gas storage
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5,382	3,861
Electrical & mechanical specialty contracting
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	439,378	590,263
Transmission & distribution specialty contracting
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	176,860	152,022
Other
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	22,566	20,063
Residential utility sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	302,325	365,476
Commercial utility sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	203,645	241,274
Industrial utility sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	25,928	27,601
Other utility sales
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,936	1,774
Electric \| Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(28)	(27)
Electric \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	109,624	98,560
Other revenues	(1,897)	(2,863)
Total external operating revenues	107,727	95,697
Electric \| Natural gas transportation \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric \| Natural gas storage \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric \| Electrical & mechanical specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric \| Transmission & distribution specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Electric \| Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	15,630	11,878
Electric \| Residential utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	39,222	37,825
Electric \| Commercial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	41,515	36,347
Electric \| Industrial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	11,349	10,763
Electric \| Other utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,936	1,774
Natural gas distribution \| Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(56)	(70)
Natural gas distribution \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	457,548	567,571
Other revenues	1,921	(1,974)
Total external operating revenues	459,469	565,597
Natural gas distribution \| Natural gas transportation \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	14,591	13,504
Natural gas distribution \| Natural gas storage \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Natural gas distribution \| Electrical & mechanical specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Natural gas distribution \| Transmission & distribution specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Natural gas distribution \| Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	3,201	4,721
Natural gas distribution \| Residential utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	263,103	327,651
Natural gas distribution \| Commercial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	162,130	204,927
Natural gas distribution \| Industrial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	14,579	16,838
Natural gas distribution \| Other utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(30,311)	(26,270)
Pipeline \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	20,964	14,433
Other revenues	47	38
Total external operating revenues	21,011	14,471
Pipeline \| Natural gas transportation \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	43,637	34,983
Pipeline \| Natural gas storage \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	5,382	3,861
Pipeline \| Electrical & mechanical specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Transmission & distribution specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	2,256	1,859
Pipeline \| Residential utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Commercial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Industrial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Pipeline \| Other utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(87)	0
Construction services \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	616,197	742,318
Other revenues	9,405	12,015
Total external operating revenues	625,602	754,333
Construction services \| Natural gas transportation \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Natural gas storage \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Electrical & mechanical specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	439,378	590,263
Construction services \| Transmission & distribution specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	176,860	152,022
Construction services \| Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	46	33
Construction services \| Residential utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Commercial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Industrial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Construction services \| Other utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Intersegment eliminations
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	(1,417)	(1,572)
Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	16	0
Other revenues	0	0
Total external operating revenues	16	0
Other \| Natural gas transportation \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Natural gas storage \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Electrical & mechanical specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Transmission & distribution specialty contracting \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Other \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	1,433	1,572
Other \| Residential utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Commercial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Industrial utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	0	0
Other \| Other utility sales \| Operating Segments
Disaggregation of Revenue [Line Items]
Revenues from contracts with customers	$ 0	$ 0

Revenue from contracts with c_5

Revenue from contracts with customers - Contract balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Construction contractor, contract cost, subject to uncertainty, amount	$ 31,000
Contract assets	165,924		$ 158,861
Change in contract assets	7,063
Contract liabilities - current	(187,741)		(202,144)
Change in contract liabilities - current	14,403
Contract liabilities - noncurrent	(2,161)		(291)
Change in contract liabilities - noncurrent	(1,870)
Net contract liabilities	(23,978)		$ (43,574)
Change in net contract assets (liabilities)	19,596
Contract with customer, liability, revenue recognized	97,600	$ 134,600
Amounts from performance obligations satisfied in prior periods	$ 33,400	$ 17,700

Leases (Details)

Leases (Details) - USD ($) $ in Millions	3 Months Ended
Leases (Details) - USD ($) $ in Millions	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Operating lease, lease income	$ 9.5	$ 12.2
Lease receivables	$ 8.5

Regulatory assets and liabili_3

Regulatory assets and liabilities - Schedule of Unamortized Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Regulatory Asset [Abstract]
Current regulatory assets	$ 158,614	$ 172,492	$ 216,318
Regulatory assets	414,433	447,099	349,500
Total regulatory assets	573,047	619,591	565,818
Regulatory Liability [Abstract]
Regulatory liabilities due within one year	90,115	70,761	44,395
Regulatory liabilities	523,484	521,050	454,669
Total regulatory liabilities	613,599	591,811	499,064
Net regulatory position	$ (40,552)	27,780	66,754
Natural gas costs refundable through rate adjustments
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 54,282	43,161	6,331
Provision for rate refund
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 6,517	6,866	1,115
Cost recovery mechanisms
Regulatory Liability [Abstract]
Regulatory liabilities due within one year	5,642	6,284	2,926
Regulatory liabilities	$ 24,269	21,791	16,313
Conservation programs
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 3,576	2,130	3,834
Margin sharing
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 2,869	5,243	0
Taxes recoverable from customers
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 1,991	2,149	1,513
Regulatory liabilities	$ 190,850	193,578	200,879
Refundable fuel and electric costs
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 1,122	263	1,179
Electric fuel and purchased power deferral
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Regulatory liabilities due within one year	$ 746	0	9,630
Other
Regulatory Liability [Abstract]
Regulatory liabilities due within one year	13,370	4,665	17,867
Regulatory liabilities	1,927	1,809	1,638
Plant to be retired
Regulatory Liability [Abstract]
Regulatory liabilities	220,519	220,147	214,467
Environmental compliance programs
Regulatory Liability [Abstract]
Regulatory liabilities	63,746	61,941	0
Accumulated deferred investment tax credit
Regulatory Liability [Abstract]
Regulatory liabilities	16,129	15,740	13,996
Pension and postretirement benefits
Regulatory Liability [Abstract]
Regulatory liabilities	$ 6,044	6,044	7,376
Minimum \| Cost recovery mechanisms
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Minimum \| Other
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	1 year
Maximum \| Cost recovery mechanisms
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	18 years
Maximum \| Other
Regulatory Liability [Abstract]
Estimated Recovery or Refund Period	14 years
Natural gas costs recoverable through rate adjustments
Regulatory Asset [Abstract]
Current regulatory assets	$ 110,481	98,844	198,166
Regulatory assets	$ 25,915	55,493	0
Natural gas costs recoverable through rate adjustments \| Minimum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Natural gas costs recoverable through rate adjustments \| Maximum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	2 years
Electric fuel and purchased power deferral
Regulatory Asset [Abstract]
Current regulatory assets	$ 17,061	33,918	3,279
Regulatory assets	$ 15,612	0	0
Electric fuel and purchased power deferral \| Minimum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Electric fuel and purchased power deferral \| Maximum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	2 years
Conservation programs
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Current regulatory assets	$ 13,735	14,425	8,599
Environmental compliance programs
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Current regulatory assets	$ 7,443	5,525	1,191
Regulatory assets	50,372	66,806	21,942
Cost recovery mechanisms
Regulatory Asset [Abstract]
Current regulatory assets	6,454	9,153	3,954
Regulatory assets	$ 84,546	85,944	65,732
Cost recovery mechanisms \| Minimum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Cost recovery mechanisms \| Maximum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	25 years
Other
Regulatory Asset [Abstract]
Current regulatory assets	$ 3,440	10,627	1,129
Regulatory assets	$ 8,846	8,588	11,430
Other \| Minimum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	1 year
Other \| Maximum
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	15 years
Pension and postretirement benefits
Regulatory Asset [Abstract]
Regulatory assets	$ 142,511	142,511	143,349
Plant costs/asset retirement obligations
Regulatory Asset [Abstract]
Regulatory assets	45,702	46,009	44,131
Manufactured gas plant site remediation
Regulatory Asset [Abstract]
Regulatory assets	25,851	26,127	26,605
Taxes recoverable from customers
Regulatory Asset [Abstract]
Regulatory assets	$ 12,331	12,249	12,198
Long-term debt refinancing costs
Regulatory Asset [Abstract]
Estimated Recovery or Refund Period	36 years
Regulatory assets	$ 2,453	2,600	3,041
Plant to be retired
Regulatory Asset [Abstract]
Regulatory assets	$ 294	$ 772	$ 21,072

Regulatory assets and liabili_4

Regulatory assets and liabilities - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory assets not earning a rate of return	$ 191.7	$ 194.3	$ 255.6

Fair value measurements - Narra

Fair value measurements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Available-for-sale securities [Line Items]
Investments used to satisfy nonqualified benefit plans obligations	$ 62.7	$ 66.2	$ 83.5
Net unrealized gain (loss) on investments used to satisfy obligations under nonqualified benefit plans	2.9		$ 2.9
Investment withdrawal, reduction in cost basis	$ 9	$ 20

Fair value measurements - Avail

Fair value measurements - Available-for-Sale Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Available-for-sale securities [Abstract]
Cost	$ 11,828	$ 11,755	$ 11,580
Gross Unrealized Gains	39	45	11
Gross Unrealized Losses	509	478	612
Fair Value	11,358	11,322	10,979
Mortgage-backed securities
Available-for-sale securities [Abstract]
Cost	8,072	8,234	8,557
Gross Unrealized Gains	4	17	3
Gross Unrealized Losses	507	470	561
Fair Value	7,569	7,781	7,999
U.S. Treasury securities
Available-for-sale securities [Abstract]
Cost	3,756	3,521	3,023
Gross Unrealized Gains	35	28	8
Gross Unrealized Losses	2	8	51
Fair Value	$ 3,789	$ 3,541	$ 2,980

Fair value measurements - Sched

Fair value measurements - Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Concentration risks, percentage [Abstract]
Percentage in fixed-income and other investments	57%	60%	61%
Percentage investment in common stock of large-cap companies	17%	15%	15%
Percentage investment in target date investments	10%	8%	7%
Percentage investment in common stock of mid-cap companies	8%	7%	8%
Percentage investment in common stock of small-cap companies	4%	5%	6%
Percentage investment in cash and cash equivalents	3%	3%	2%
Percentage investment in international investments	1%	1%	1%
Percentage investment in high-yield investments		1%
Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	$ 81,056	$ 84,014	$ 99,886
Fair Value, Inputs, Level 1 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Fair value, inputs, level 2 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	81,056	84,014	99,886
Fair Value, Inputs, Level 3 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Money market funds \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	6,985	6,409	5,447
Money market funds \| Fair Value, Inputs, Level 1 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Money market funds \| Fair value, inputs, level 2 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	6,985	6,409	5,447
Money market funds \| Fair Value, Inputs, Level 3 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Insurance contracts \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	62,713	66,283	83,460
Insurance contracts \| Fair Value, Inputs, Level 1 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Insurance contracts \| Fair value, inputs, level 2 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	62,713	66,283	83,460
Insurance contracts \| Fair Value, Inputs, Level 3 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Mortgage-backed securities \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	7,569	7,781	7,999
Mortgage-backed securities \| Fair Value, Inputs, Level 1 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
Mortgage-backed securities \| Fair value, inputs, level 2 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	7,569	7,781	7,999
Mortgage-backed securities \| Fair Value, Inputs, Level 3 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
U.S. Treasury securities \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	3,789	3,541	2,980
U.S. Treasury securities \| Fair Value, Inputs, Level 1 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	0	0	0
U.S. Treasury securities \| Fair value, inputs, level 2 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	3,789	3,541	2,980
U.S. Treasury securities \| Fair Value, Inputs, Level 3 \| Fair value, measurements, recurring
Fair value measurements [Line Items]
Assets, fair value disclosure	$ 0	$ 0	$ 0

Fair value measurements - Fair

Fair value measurements - Fair Value, by Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Fair value, balance sheet grouping [Line Items]
Long-term debt	$ 2,386,397	$ 2,298,223	$ 2,239,717
Carrying amount
Fair value, balance sheet grouping [Line Items]
Long-term debt	2,386,397	2,298,223	2,239,718
Fair value
Fair value, balance sheet grouping [Line Items]
Long-term debt, fair value	$ 2,098,002	$ 2,046,039	$ 1,974,344

Debt - Short-Term Debt (Details

Debt - Short-Term Debt (Details) - USD ($) $ in Thousands			1 Months Ended			3 Months Ended
Debt - Short-Term Debt (Details) - USD ($) $ in Thousands	Jan. 19, 2024	Dec. 05, 2023	May 31, 2023	Apr. 30, 2023	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023	Jan. 20, 2023
Short-Term Debt [Line Items]
Short-term borrowings					$ 293,500	$ 0	$ 293,500	$ 95,000
Repayment of short-term borrowings						$ 95,000	$ 20,000
Term Loan Agreement \| Cascade Natural Gas
Short-Term Debt [Line Items]
Short-term borrowings									$ 150,000
Repayment of short-term borrowings	$ 50,000	$ 100,000
Term Loan Agreement \| Intermountain Gas Company
Short-Term Debt [Line Items]
Short-term borrowings									$ 125,000
Repayment of short-term borrowings	$ 45,000		$ 30,000	$ 30,000	$ 20,000

Debt - Long-Term Debt Outstandi

Debt - Long-Term Debt Outstanding (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Long-term debt outstanding [Line Items]
Less unamortized debt issuance costs	$ 6,760	$ 6,357	$ 5,174
Less discount	0	0	284
Long-term debt	2,386,397	2,298,223	2,239,717
Less current maturities	60,700	61,319	47,819
Long-term debt	$ 2,325,697	2,236,904	2,191,898
Senior Notes
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	4.46%
Long-term debt, gross	$ 1,882,000	1,882,000	1,848,500
Term Loan Agreements
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	6.48%
Long-term debt, gross	$ 196,300	196,300	7,000
Commercial Paper
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	5.72%
Long-term debt, gross	$ 158,800	144,200	264,540
Credit Agreements
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	8.57%
Long-term debt, gross	$ 120,700	46,100	89,144
Medium-term Notes
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	7.32%
Long-term debt, gross	$ 35,000	35,000	35,000
Other Notes
Long-term debt outstanding [Line Items]
Weighted Average Interest Rate	6%
Long-term debt, gross	$ 357	$ 980	$ 991

Debt - Schedule of Debt Maturit

Debt - Schedule of Debt Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Debt Disclosure [Abstract]
Remainder of 2024	$ 60,700
2025	347,700
2026	140,700
2027	141,400
2028	234,500
Thereafter	$ 1,468,157

Cash flow information - Schedul

Cash flow information - Schedule of Cash Flow, Supplemental Disclosures (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Supplemental Cash Flow Information [Abstract]
Interest, net	$ 21,155	$ 21,362
Income taxes paid, net	(257)	7,972
AFUDC borrowed	2,700	2,400
Right-of-use assets obtained in exchange for new operating lease liabilities	12,735	13,201	$ 46,181
Property, plant and equipment additions in accounts payable	$ 32,972	$ 29,564	$ 46,622

Business segment data - Schedul

Business segment data - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 1,213,825	$ 1,430,098
Operating income	135,947	118,521
Income from continuing operations	100,898	83,875
Discontinued operations, net of tax	0	(45,522)
Net income	100,898	38,353
Operating Segments
Segment Reporting Information [Line Items]
Revenues	1,244,291	1,456,465
Operating Segments \| Electric
Segment Reporting Information [Line Items]
Revenues	107,727	95,697
Operating income	22,788	21,091
Operating Segments \| Natural gas distribution
Segment Reporting Information [Line Items]
Revenues	459,469	565,597
Operating income	58,238	58,505
Operating Segments \| Pipeline
Segment Reporting Information [Line Items]
Revenues	21,011	14,471
Operating income	22,650	13,040
Operating Segments \| Construction services
Segment Reporting Information [Line Items]
Revenues	625,602	754,333
Operating income	38,884	35,217
Operating Segments \| Other
Segment Reporting Information [Line Items]
Revenues	16	0
Operating income	(6,613)	(9,332)
Intersegment eliminations
Segment Reporting Information [Line Items]
Revenues	(31,899)	(27,939)
Regulated operation
Segment Reporting Information [Line Items]
Revenues	586,017	673,932
Income from continuing operations	73,343	64,464
Regulated operation \| Operating Segments
Segment Reporting Information [Line Items]
Revenues	586,017	673,932
Regulated operation \| Operating Segments \| Electric
Segment Reporting Information [Line Items]
Revenues	107,727	95,697
Income from continuing operations	17,869	16,607
Regulated operation \| Operating Segments \| Natural gas distribution
Segment Reporting Information [Line Items]
Revenues	459,469	565,597
Income from continuing operations	40,070	38,928
Regulated operation \| Operating Segments \| Pipeline
Segment Reporting Information [Line Items]
Revenues	18,821	12,638
Income from continuing operations	15,404	8,929
Regulated operation \| Intersegment eliminations
Segment Reporting Information [Line Items]
Revenues	(30,359)	(26,356)
Regulated operation \| Intersegment eliminations \| Electric
Segment Reporting Information [Line Items]
Revenues	(28)	(27)
Regulated operation \| Intersegment eliminations \| Natural gas distribution
Segment Reporting Information [Line Items]
Revenues	(56)	(70)
Regulated operation \| Intersegment eliminations \| Pipeline
Segment Reporting Information [Line Items]
Revenues	(30,275)	(26,259)
Nonregulated operation
Segment Reporting Information [Line Items]
Revenues	627,808	756,166
Income from continuing operations	27,555	19,411
Nonregulated operation \| Operating Segments
Segment Reporting Information [Line Items]
Revenues	627,808	756,166
Nonregulated operation \| Operating Segments \| Pipeline
Segment Reporting Information [Line Items]
Revenues	2,190	1,833
Income from continuing operations	(346)	(458)
Nonregulated operation \| Operating Segments \| Construction services
Segment Reporting Information [Line Items]
Revenues	625,602	754,333
Income from continuing operations	28,214	28,809
Nonregulated operation \| Operating Segments \| Other
Segment Reporting Information [Line Items]
Revenues	16	0
Income from continuing operations	(313)	(8,940)
Nonregulated operation \| Intersegment eliminations
Segment Reporting Information [Line Items]
Revenues	(1,540)	(1,583)
Nonregulated operation \| Intersegment eliminations \| Pipeline
Segment Reporting Information [Line Items]
Revenues	(36)	(11)
Nonregulated operation \| Intersegment eliminations \| Construction services
Segment Reporting Information [Line Items]
Revenues	(87)	0
Nonregulated operation \| Intersegment eliminations \| Other
Segment Reporting Information [Line Items]
Revenues	$ (1,417)	$ (1,572)

Business segment data - Operati

Business segment data - Operating Revenues Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ 1,213,825	$ 1,430,098
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,244,291	1,456,465
Corporate, Non-Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	1,433	1,572
Intersegment eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenues	$ (31,899)	$ (27,939)

Employee benefit plans - Compon

Employee benefit plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Pension benefits
Defined benefit plan disclosure, net periodic benefit cost [Line Items]
Interest cost	$ 3,200	$ 3,380
Expected return on assets	(4,028)	(4,298)
Amortization of net actuarial gain (loss)	1,037	773
Net periodic benefit cost (credit)	209	(145)
Other postretirement benefits
Defined benefit plan disclosure, net periodic benefit cost [Line Items]
Service cost	126	138
Interest cost	459	489
Expected return on assets	(1,329)	(1,348)
Amortization of prior service credit	(330)	(330)
Amortization of net actuarial gain (loss)	(72)	(168)
Net periodic benefit credit, including amount capitalized	(1,146)	(1,219)
Less amount capitalized	22	24
Net periodic benefit cost (credit)	$ (1,168)	$ (1,243)

Employee benefit plans - Narrat

Employee benefit plans - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Supplemental employee retirement plans
Defined benefit plan disclosure, net periodic benefit cost [Line Items]
Net periodic benefit cost (credit)	$ 733	$ 746

Regulatory matters - NDPSC (Det

Regulatory matters - NDPSC (Details) - Natural gas distribution - NDPSC - Montana-Dakota Utilities Co. - Pending Rate Case - USD ($) $ in Millions	Dec. 13, 2023	Nov. 01, 2023
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount		$ 11.6
Public utilities, requested rate increase (decrease), percentage		7.50%
Public utilities, interim rate increase (decrease), amount	$ 10.1
Public utilities, interim rate increase (decrease), percentage	6.50%

Regulatory matters - SDPUC (Det

Regulatory matters - SDPUC (Details) - Pending Rate Case - SDPUC - Montana-Dakota Utilities Co. - USD ($) $ in Millions	Jan. 26, 2024	Aug. 15, 2023
Electric
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount		$ 3
Public utilities, requested rate increase (decrease), percentage		17.30%
Natural gas distribution
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount		$ 7.4
Public utilities, requested rate increase (decrease), percentage		11.20%
Public utilities, interim rate increase (decrease), amount	$ 2.7
Public utilities, interim rate increase (decrease), percentage	15.40%

Regulatory matters - WUTC (Deta

Regulatory matters - WUTC (Details) - Natural gas distribution - WUTC - Cascade Natural Gas $ in Millions	Mar. 29, 2024 USD ($)
Pending Rate Case, Multi-Year, Year One
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 43.8
Public utilities, requested rate increase (decrease), percentage	11.60%
Pending Rate Case, Multi-Year, Year Two
Public Utilities, General Disclosures [Line Items]
Public utilities, requested rate increase (decrease), amount	$ 11.7
Public utilities, requested rate increase (decrease), percentage	2.80%

Contingencies - Litigation (Det

Contingencies - Litigation (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Commitments and Contingencies Disclosure [Abstract]
Potential liabilities related to litigation and environmental matters	$ 22,900	$ 22,500	$ 23,400
Loss contingency, receivable	80	202	2,000
Loss contingency, regulatory asset	$ 21,600	$ 21,600	$ 20,900

Contingencies - Guarantees (Det

Contingencies - Guarantees (Details)	Mar. 31, 2024 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Guarantor obligations, maximum exposure, undiscounted	$ 329,900,000
Fixed maximum amounts guaranteed by year 2024	53,000,000
Fixed maximum amounts guaranteed by year 2025	210,700,000
Fixed maximum amounts guaranteed by year 2026	64,900,000
Fixed maximum amounts guaranteed by year 2027	1,000,000
Fixed maximum amounts guaranteed by year 2028	300,000
Fixed maximum amounts guaranteed, thereafter	0
Amount outstanding under guarantees that is reflected on balance sheet	0
Letters of credit	14,300,000
Letters of credit set to expire - 2023	12,300,000
Letters of credit set to expire - 2025	2,000,000
Outstanding letters of credit	0
Amount of surety bonds outstanding	$ 738,100,000

Contingencies - Variable Intere

Contingencies - Variable Interest Entities (Details) $ in Millions	Mar. 31, 2024 USD ($)
Fuel contract
Variable Interest Entities [Line Items]
Variable interest entity, reporting entity involvement, maximum loss exposure, amount	$ 27.1

Subsequent event (Details)

Subsequent event (Details) - Term Loan Agreement - WBI Energy Transmission - Subsequent Event $ in Millions	Apr. 01, 2024 USD ($)
Subsequent Events [Line Items]
Debt instrument, face amount	$ 60
Interest rate, stated percentage	4.52%
Ratio of total debt to total capitalization	65%