CSX (CSX) 10-K10 Feb 212020 FY Annual reportFinancial data

Company Profile

Cover

Cover - USD ($) $ in Billions	12 Months Ended
Cover - USD ($) $ in Billions	Dec. 31, 2020	Jan. 31, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	1-8022
Entity Registrant Name	CSX CORPORATION
Entity Incorporation, State or Country Code	VA
Entity Tax Identification Number	62-1051971
Entity Address, Address Line One	500 Water Street
Entity Address, Address Line Two	15th Floor
Entity Address, City or Town	Jacksonville
Entity Address, State or Province	FL
Entity Address, Postal Zip Code	32202
City Area Code	904
Local Phone Number	359-3200
Title of 12(b) Security	Common Stock, $1 Par Value
Trading Symbol	CSX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
ICFR Auditor Attestation Flag	true
Entity Public Float			$ 53
Entity Common Stock, Shares Outstanding		762,505,058
Documents Incorporated by Reference	Portions of the Registrant’s Definitive Proxy Statement (the “Proxy Statement”) to be filed no later than 120 days after the end of the fiscal year with respect to its 2020 annual meeting of shareholders.
Entity Central Index Key	0000277948
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false

CONSOLIDATED INCOME STATEMENTS

CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	[1]	Dec. 31, 2018	[1]
Income Statement [Abstract]
Revenue	$ 10,583	$ 11,937		$ 12,250
Expense
Labor and Fringe	2,275	2,616		2,738
Materials, Supplies and Other	1,684	1,749		1,931
Depreciation	1,383	1,349		1,331
Fuel	541	906		1,046
Equipment and Other Rents	338	352		335
Total Expense	6,221	6,972		7,381
Operating Income	4,362	4,965		4,869
Interest Expense	(754)	(737)		(639)
Other Income - Net (Note 14)	19	88		74
Earnings Before Income Taxes	3,627	4,316		4,304
Income Tax Expense (Note 12)	(862)	(985)		(995)
Net Earnings	$ 2,765	$ 3,331		$ 3,309
Net Earnings Per Share
Basic (in dollars per share)	$ 3.61	$ 4.18		$ 3.86
Assuming Dilution (in dollars per share)	$ 3.60	$ 4.17		$ 3.84
Average Common Shares Outstanding (Millions)
Basic (shares)	766	796		857
Assuming Dilution (shares)	768	798		861

[1]	Certain prior year data has been reclassified to conform to the current presentation.

CONSOLIDATED COMPREHENSIVE INCO

CONSOLIDATED COMPREHENSIVE INCOME STATEMENTS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Earnings	$ 2,765	$ 3,331	[1]	$ 3,309	[1]
Other Comprehensive Income (Loss) - Net of Tax:
Pension and Other Post-Employment Benefits	21	(15)		(164)
Interest Rate Derivatives	62	0		0
Other	(6)	1		(11)
Total Other Comprehensive Income (Loss) (Note 16)	77	(14)		(175)
Total Comprehensive Earnings	$ 2,842	$ 3,317		$ 3,134

[1]	Certain prior year data has been reclassified to conform to the current presentation.

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	[1]
Current Assets:
Cash and Cash Equivalents	$ 3,129	$ 958
Short-term Investments	2	996
Accounts Receivable - Net (Note 11)	912	986
Materials and Supplies	302	261
Other Current Assets	96	77
Total Current Assets	4,441	3,278
Properties	45,530	45,100
Accumulated Depreciation	(13,086)	(12,932)
Properties - Net (Note 6)	32,444	32,168
Investment in Affiliates and Other Companies (Note 15)	1,985	1,879
Right of Use Lease Asset (Note 7)	472	532
Other Long-term Assets	451	400
Total Assets	39,793	38,257
Current Liabilities:
Accounts Payable	809	1,043
Labor and Fringe Benefits Payable	482	489
Casualty, Environmental and Other Reserves (Note 5)	90	100
Current Maturities of Long-term Debt (Note 10)	401	245
Income and Other Taxes Payable	73	69
Other Current Liabilities	164	205
Total Current Liabilities	2,019	2,151
Casualty, Environmental and Other Reserves (Note 5)	224	205
Long-term Debt (Note 9)	16,304	15,993
Deferred Income Taxes - Net (Note 12)	7,168	6,961
Long-term Lease Liability (Note 7)	455	493
Other Long-term Liabilities	513	591
Total Liabilities	26,683	26,394
Shareholders' Equity:
Common Stock, $1 Par Value (Note 3)	763	773
Other Capital	409	346
Retained Earnings (Note 1)	12,527	11,404
Accumulated Other Comprehensive Loss (Note 16)	(598)	(675)
Non-controlling Minority Interest	9	15
Total Shareholders' Equity	13,110	11,863
Total Liabilities and Shareholders' Equity	$ 39,793	$ 38,257

[1]	Certain prior year data has been reclassified to conform to the current presentation.

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock par value (in dollars per share)	$ 1	$ 1

CONSOLIDATED CASH FLOW STATEMEN

CONSOLIDATED CASH FLOW STATEMENTS - USD ($) $ in Millions	12 Months Ended
CONSOLIDATED CASH FLOW STATEMENTS - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
OPERATING ACTIVITIES
Net Earnings	$ 2,765	$ 3,331	[1]	$ 3,309	[1]
Adjustments to Reconcile Net Earnings to Net Cash
Depreciation	1,383	1,349	[1]	1,331	[1]
Deferred Income Taxes	180	273		279
Gains on Property Dispositions	(35)	(151)		(154)
Cash Payments for Restructuring Charge	0	0		(15)
Other Operating Activities	(32)	(69)		(117)
Changes in Operating Assets and Liabilities:
Accounts Receivable	83	45		(46)
Other Current Assets	(75)	68		101
Accounts Payable	(20)	98		104
Income and Other Taxes Payable	39	2		(104)
Other Current Liabilities	(25)	(96)		(47)
Net Cash Provided by Operating Activities	4,263	4,850		4,641
INVESTING ACTIVITIES
Property Additions	(1,626)	(1,657)		(1,745)
Purchases of Short-term Investments	(426)	(2,838)		(736)
Proceeds from Sales of Short-term Investments	1,424	2,108		505
Proceeds from Property Dispositions	56	254		319
Other Investing Activities	(77)	31		(27)
Net Cash Used in Investing Activities	(649)	(2,102)		(1,684)
FINANCING ACTIVITIES
Long-term Debt Issued (Note 10)	1,000	2,000		3,000
Long-term Debt Repaid (Note 10)	(745)	(518)		(19)
Dividends Paid	(797)	(763)		(751)
Shares Repurchased	(867)	(3,373)		(4,671)
Other Financing Activities	(34)	6		(59)
Net Cash Used in Financing Activities	(1,443)	(2,648)		(2,500)
Net Increase in Cash and Cash Equivalents	2,171	100		457
CASH AND CASH EQUIVALENTS
Cash and Cash Equivalents at Beginning of Period	958	858		401
Cash and Cash Equivalents at End of Period	3,129	958		858
SUPPLEMENTAL CASH FLOW INFORMATION
Interest Paid - Net of Amounts Capitalized	750	717		614
Income Taxes Paid	$ 664	$ 691		$ 814

[1]	Certain prior year data has been reclassified to conform to the current presentation.

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Millions	Total		Common Shares Outstanding	Common Stock and Other Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)		Non- controlling Minority Interest
Stockholders' Equity, beginning balance (in shares) at Dec. 31, 2017			889,851
Shareholders' Equity, beginning balance at Dec. 31, 2017	$ 14,721			$ 1,107	$ 14,084	$ (486)	[1]	$ 16
Comprehensive Earnings:
Net Earnings	3,309	[2]			3,309
Total Other Comprehensive Income (Loss) (Note 16)	(175)					(175)	[1]
Total Comprehensive Earnings	3,134
Common stock dividends, per share	$ (751)				(751)
Share Repurchases (in shares)	(72,000)		(72,264)
Share Repurchases	$ (4,671)			(72)	(4,599)
Other (in shares)			593
Other	147			32	114			1
Stockholders' Equity, ending balance (in shares) at Dec. 31, 2018			818,180
Shareholders' Equity, ending balance at Dec. 31, 2018	12,580			1,067	12,157	(661)	[1]	17
Comprehensive Earnings:
Accumulated other comprehensive loss, tax						180
Net Earnings	3,331	[2]			3,331
Total Other Comprehensive Income (Loss) (Note 16)	(14)					(14)	[1]
Total Comprehensive Earnings	3,317
Common stock dividends, per share	$ (763)				(763)
Share Repurchases (in shares)	(48,000)		(47,819)
Share Repurchases	$ (3,373)			(48)	(3,325)
Other (in shares)			3,110
Other	102			100	4			(2)
Stockholders' Equity, ending balance (in shares) at Dec. 31, 2019			773,471
Shareholders' Equity, ending balance at Dec. 31, 2019	11,863	[2]		1,119	11,404	(675)	[1]	15
Comprehensive Earnings:
Accumulated other comprehensive loss, tax						184
Net Earnings	2,765				2,765
Total Other Comprehensive Income (Loss) (Note 16)	77					77	[1]
Total Comprehensive Earnings	2,842
Common stock dividends, per share	$ (797)				(797)
Share Repurchases (in shares)	(13,000)		(12,614)
Share Repurchases	$ (867)			(13)	(854)
Other (in shares)			1,672
Other	$ 69			66	9			(6)
Stockholders' Equity, ending balance (in shares) at Dec. 31, 2020	763,000		762,529
Shareholders' Equity, ending balance at Dec. 31, 2020	$ 13,110			$ 1,172	$ 12,527	(598)	[1]	$ 9
Comprehensive Earnings:
Accumulated other comprehensive loss, tax						$ 156

[1]	Accumulated Other Comprehensive Loss year-end balances shown above are net of tax. The associated taxes were $156 million, $184 million and $180 million for 2020, 2019 and 2018, respectively. For additional information see Note 16, Other Comprehensive Income.
[2]	Certain prior year data has been reclassified to conform to the current presentation.

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Stockholders' Equity [Abstract]
Common stock dividends, per share (in dollars per share)	$ 1.04	$ 0.96	$ 0.88

Nature of Operations and Signif

Nature of Operations and Significant Accounting Policies	12 Months Ended
Nature of Operations and Significant Accounting Policies	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Significant Accounting Policies	Nature of Operations and Significant Accounting Policies Business CSX Corporation together with its subsidiaries ("CSX" or the “Company”), based in Jacksonville, Florida, is one of the nation's leading transportation companies. The Company provides rail-based transportation services including traditional rail service, the transport of intermodal containers and trailers, as well as other transportation services such as rail-to-truck transfers and bulk commodity operations. CSX Transportation, Inc. CSX’s principal operating subsidiary, CSX Transportation, Inc. (“CSXT”), provides an important link to the transportation supply chain through its approximately 19,500 route mile rail network, which serves major population centers in 23 states east of the Mississippi River, the District of Columbia and the Canadian provinces of Ontario and Quebec. It has access to over 70 ocean, river and lake port terminals along the Atlantic and Gulf Coasts, the Mississippi River, the Great Lakes and the St. Lawrence Seaway. The Company’s intermodal business links customers to railroads via trucks and terminals. CSXT also serves thousands of production and distribution facilities through track connections to more than 230 short-line and regional railroads. CSXT is also responsible for the Company's real estate sales, leasing, acquisition and management and development activities. Substantially all of these activities are focused on supporting railroad operations. Other Entities In addition to CSXT, the Company’s subsidiaries include CSX Intermodal Terminals, Inc. (“CSX Intermodal Terminals”), Total Distribution Services, Inc. (“TDSI”), Transflo Terminal Services, Inc. (“Transflo”), CSX Technology, Inc. (“CSX Technology”) and other subsidiaries. CSX Intermodal Terminals owns and operates a system of intermodal terminals, predominantly in the eastern United States, and also provides drayage services (the pickup and delivery of intermodal shipments) for certain customers. TDSI serves the automotive industry with distribution centers and storage locations. Transflo connects non-rail served customers to the many benefits of rail by transferring products from rail to trucks. The biggest Transflo markets are chemicals and agriculture, which include shipments of plastics and ethanol. CSX Technology and other subsidiaries provide support services for the Company. Acquisition of Pan-Am Railways On November 30, 2020, CSX signed a definitive agreement to acquire Pan Am Railways, Inc. (“Pan Am”) which owns and operates a highly integrated, nearly 1,200-mile rail network and has a partial interest in the more than 600-mile Pan Am Southern system. This will expand CSX’s reach in Connecticut, New York and Massachusetts while adding Vermont, New Hampshire and Maine to its existing network. A $30 million deposit paid by the Company related to its agreement to acquire Pan Am is included in other investing activities on the consolidated cash flow statement. This transaction remains subject to regulatory review and approval by the Surface Transportation Board. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Lines of Business During 2020, the Company's services generated $10.6 billion of revenue and served three primary lines of business: merchandise, intermodal and coal. • The merchandise business shipped 2.5 million carloads (43 percent of volume) and generated 67 percent of revenue in 2020. The Company’s merchandise business is comprised of shipments in the following diverse markets: chemicals, agricultural and food products, automotive, minerals, forest products, metals and equipment, and fertilizers. • The intermodal business shipped 2.7 million units (46 percent of volume) and generated 16 percent of revenue in 2020. The intermodal business combines the superior economics of rail transportation with the flexibility of trucks and offers a cost and environmental advantage over long-haul trucking. Through a network of approximately 30 terminals, the intermodal business serves all major markets east of the Mississippi River and transports mainly manufactured consumer goods in containers, providing customers with truck-like service for longer shipments. • The coal business shipped 637 thousand carloads (11 percent of volume) and generated 13 percent of revenue in 2020. The Company transports domestic coal, coke and iron ore to electricity-generating power plants, steel manufacturers and industrial plants as well as export coal to deep-water port facilities. Approximately one-quarter to one-third of export coal and the majority of the domestic coal that the Company transports is used for generating electricity or industrial purposes. Other revenue accounted for 4 percent of the Company’s total revenue in 2020. This revenue category includes revenue from regional subsidiary railroads, demurrage, storage at intermodal facilities, revenue for customer volume commitments not met, switching, other incidental charges and adjustments to revenue reserves. Revenue from regional railroads includes shipments by railroads that the Company does not directly operate. Demurrage represents charges assessed when freight cars or other equipment are held beyond a specified period of time. Switching represents charges assessed when a railroad switches cars for a customer or another railroad. Employees The Company's number of employees was nearly 19,300 as of December 2020, which includes approximately 15,700 union employees. Most of the Company’s employees provide or support transportation services. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Basis of Presentation In the opinion of management, the accompanying consolidated financial statements contain all normal, recurring adjustments necessary to fairly present the financial position of CSX and its subsidiaries at December 31, 2020 and December 31, 2019, and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2020, 2019 and 2018. Where applicable, prior year information has been reclassified to conform to current presentation. In addition, management has evaluated and disclosed all material events occurring subsequent to the date of the financial statements up to the date this annual report is filed on Form 10-K. Fiscal Year The Company's fiscal periods are based upon the calendar year. Except as otherwise specified, references to full years indicate CSX’s fiscal years ended on December 31, 2020, December 31, 2019 and December 31, 2018. Principles of Consolidation The consolidated financial statements include results of operations of CSX and subsidiaries over which CSX has majority ownership or financial control. All significant intercompany accounts and transactions have been eliminated. Most investments in companies that were not majority-owned were carried at cost (if less than 20% owned and the Company has no significant influence) or were accounted for under the equity method (if the Company has significant influence but does not have control). These investments are reported within Investment in Affiliates and Other Companies on the consolidated balance sheets. Cash and Cash Equivalents On a daily basis, cash in excess of current operating requirements is invested in various highly liquid investments having a typical maturity date of three months or less at the date of acquisition. These investments are carried at cost, which approximates market value, and are classified as cash equivalents. Investments Investments in instruments with original maturities greater than three months that will mature in less than one year are classified as short-term investments. Investments with original maturities of one year or greater are initially classified within other long-term assets, and the classification is re-evaluated at each balance sheet date. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Materials and Supplies Materials and supplies in the consolidated balance sheets are carried at average cost and consist primarily of parts used in the repair and maintenance of track structure, equipment, and CSXT’s freight car and locomotive fleets, as well as fuel. New Accounting Pronouncements In June 2016, the FASB issued ASU Measurement of Credit Losses on Financial Instruments, which replaces current methods for evaluating impairment of financial instruments not measured at fair value, including trade accounts receivable and certain debt securities, with a current expected credit loss model. CSX was required to adopt this new standard update by January 1, 2020. Adoption did not have a material effect on the Company's results of operations. In August 2018, the FASB issued ASU Changes to the Disclosure Requirements for Defined Benefit Plans as part of its disclosure effectiveness initiative, which modifies the disclosure requirements for employer-sponsored defined benefit pension and other postretirement plans. CSX was required to adopt this new standard update by January 1, 2020. Adoption did not have a material impact on the Company's disclosures. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires that management make estimates in reporting the amounts of certain assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of certain revenues and expenses during the reporting period. Actual results may differ from those estimates. Critical accounting estimates using management judgment are made for the following areas: • personal injury, environmental and legal reserves (see Note 5, Casualty, Environmental and Other Reserves ); • pension and post-retirement medical plan accounting (see Note 9, Employee Benefit Plans ); and • depreciation policies for assets under the group-life method (see Note 6, Properties ).

Earnings Per Share

Earnings Per Share	12 Months Ended
Earnings Per Share	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share The following table sets forth the computation of basic earnings per share and earnings per share, assuming dilution: Fiscal Years 2020 2019 2018 Numerator (Dollars in Millions) : Net Earnings $ 2,765 $ 3,331 $ 3,309 Dividend Equivalents on Restricted Stock — — (1) Net Earnings, Attributable to Common Shareholders $ 2,765 $ 3,331 $ 3,308 Denominator (Units in Millions) : Average Common Shares Outstanding 766 796 857 Other Potentially Dilutive Common Shares 2 2 4 Average Common Shares Outstanding, Assuming Dilution 768 798 861 Net Earnings Per Share, Basic $ 3.61 $ 4.18 $ 3.86 Net Earnings Per Share, Assuming Dilution $ 3.60 $ 4.17 $ 3.84 Basic earnings per share is based on the weighted-average number of shares of common stock outstanding. Earnings per share, assuming dilution, is based on the weighted-average number of shares of common stock outstanding and common stock equivalents adjusted for the effects of common stock that may be issued as a result of potentially dilutive instruments. CSX's potentially dilutive instruments are made up of equity awards including performance units and employee stock options. When calculating diluted earnings per share, the potential shares that would be outstanding if all outstanding stock options were exercised are included. This number is different from outstanding stock options, which is included in Note 4, Stock Plans and Share-Based Compensation, because it is offset by shares CSX could repurchase using the proceeds from these hypothetical exercises to obtain the common stock equivalent. The total average outstanding equity awards that were excluded from the diluted earnings per share calculation because their effect was antidilutive is in the table below. Fiscal Years 2020 2019 2018 Antidilutive stock options excluded from Diluted EPS (in millions) 2 1 — Share Repurchase Programs In January 2019, the Company announced a $5 billion share repurchase program ("January 2019 program"). At December 31, 2020, approximately $889 million of authority remained under this program. On October 21, 2020, the Company announced a new, incremental $5 billion share repurchase program (“October 2020 program”). Total repurchase authority remaining as of December 31, 2020, was $5.9 billion. Previously, share repurchases were completed under a share repurchase program originally announced in October 2017 for $1.5 billion, and later increased to $5 billion in February 2018, that was completed in January 2019 ("October 2017 program"). NOTE 2. Earnings Per Share, continued Share repurchases may be made through a variety of methods including, but not limited to, open market purchases, purchases pursuant to Rule 10b5-1 plans, accelerated share repurchases and negotiated block purchases. The timing of share repurchases depends upon management's assessment of marketplace conditions and other factors, and the program remains subject to the discretion of the Board of Directors. Future share repurchases are expected to be funded by cash on hand, cash generated from operations and debt issuances. Shares are retired immediately upon repurchase. In accordance with the Equity Topic in the Accounting Standards Codification ("ASC"), the excess of repurchase price over par value is recorded in retained earnings. Share Repurchase Activity During 2020, 2019, and 2018, CSX repurchased the following shares: Fiscal Years 2020 2019 2018 Shares Repurchased (Units in Millions) 13 48 72 Cost of Shares (Dollars in Millions) $ 867 $ 3,373 $ 4,671 Average Price Paid per Share $ 68.70 $ 70.54 $ 64.64 On October 17, 2019, the Company repurchased 4.7 million shares for $319 million from MR Argent Advisor LLC, a CSX shareholder, on behalf of certain limited partners of its affiliated funds (“Mantle Ridge”) under the January 2019 share repurchase program. A member of CSX’s Board of Directors, Paul C. Hilal, founded and controls Mantle Ridge and each of its related entities. Shares purchased from Mantle Ridge are included in the table above. Accelerated Share Repurchases Shares repurchased under accelerated share repurchase agreements are included in the table above. In December 2020, the Company completed an accelerated share repurchase subject to an agreement to repurchase shares of the Company’s stock under the January 2019 program. Under this agreement, the Company paid a total of $100 million and received approximately 1.1 million shares. In August 2019, the Company entered into an accelerated share repurchase agreement under the January 2019 program. Under this accelerated share repurchase agreement, the Company made a prepayment of $250 million to a financial institution and settlement occurred in September 2019. At settlement, the Company received approximately 4 million shares, calculated based on the volume-weighted average price of the Company’s common stock over the term of the agreement, less a discount.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
Shareholders' Equity	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Common and preferred stock consists of the following: Common Stock, $1 Par Value December 2020 (Units in Millions) Common Shares Authorized 1,800 Common Shares Issued and Outstanding 763 Preferred Stock Preferred Shares Authorized 25 Preferred Shares Issued and Outstanding — Holders of common stock are entitled to one vote on all matters requiring a vote for each share held. Preferred stock is senior to common stock with respect to dividends and upon liquidation of CSX.

Stock Plans and Share-Based Com

Stock Plans and Share-Based Compensation	12 Months Ended
Stock Plans and Share-Based Compensation	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock Plans and Share-Based Compensation	Stock Plans and Share-Based Compensation Under CSX's share-based compensation plans, awards consist of performance units, stock options, restricted stock units and restricted stock awards for management and stock grants for directors. Awards granted under the various programs are determined and approved by the Compensation and Talent Management Committee of the Board of Directors. Awards to the Chief Executive Officer are approved by the full Board and awards to senior executives are approved by the Compensation and Talent Management Committee. In certain circumstances, the Chief Executive Officer or delegate approves awards to management employees other than senior executives. The Board of Directors approves awards granted to CSX's non-management directors upon recommendation of the Governance and Sustainability Committee. Share-based compensation expense for awards under share-based compensation plans and purchases made as part of the employee stock purchase plan is measured using the fair value of the award on the grant date and is recognized on a straight-line basis over the service period of the respective award or upon grant date to certain retirement-eligible employees whose agreements allow for continued vesting upon retirement. Forfeitures are recognized as they occur. Total pre-tax expense and income tax benefits associated with share-based compensation are shown in the table below. Income tax benefits include impacts from option exercises and the vesting of other equity awards. Fiscal Years (Dollars in Millions) 2020 2019 2018 Share-Based Compensation Expense Stock Options $ 19 $ 18 $ 13 Restricted Stock Units and Awards 6 8 6 Employee Stock Purchase Plan 5 4 2 Stock Awards for Directors 2 2 2 Performance Units (3) 42 28 Total Share-based Compensation Expense $ 29 $ 74 $ 51 Income Tax Benefit $ 19 $ 43 $ 26 NOTE 4. Stock Plans and Share-Based Compensation, continued Long-term Incentive Plans The objective of the CSX Long-term Incentive Plans (“LTIP”) is to motivate and reward certain employees for achieving and exceeding certain financial goals. The 2020-2022 LTIP was adopted under the 2019 Stock and Incentive Award Plan and the 2019-2021 and 2018-2020 LTIPs were adopted under the 2010 Stock and Incentive Award Plan. Grants were made in performance units, with each unit being equivalent to one share of CSX common stock, and payouts will be made in CSX common stock. The payout range for most participants will be between 0% and 200% of the target awards depending on Company performance against predetermined goals for each three-year cycle. In 2020, 2019, and 2018, target performance units were granted to certain employees under three separate LTIP plans covering three-year cycles: the 2020-2022 ("2020-2022 LTIP"), the 2019-2021 (“2019-2021 LTIP”), and the 2018-2020 (“2018-2020 LTIP”) plans. Payouts of performance units for the 2020-2022, 2019-2021 and 2018-2020 LTIP plans will be based on the achievement of certain goals, in each case excluding non-recurring items as disclosed in the Company’s financial statements. • For the 2020-2022 LTIP plan, the cumulative operating income and cumulative free cash flow over the plan period will each comprise 50% of the payout and will be measured independently of the other. Participants will receive stock dividend equivalents declared over the performance period based on the number of performance units paid upon vesting. • For the 2019-2021 LTIP plan, the cumulative operating ratio and cumulative free cash flow over the plan period will each comprise 50% of the payout and will be measured independently of the other. • For the 2018-2020 LTIP plan, the final year operating ratio and cumulative free cash flow over the plan period will each comprise 50% of the payout and will be measured independently of the other. For these plans, payouts for certain executive officers are subject to formulaic upward or downward adjustment by up to 25%, capped at an overall payout of 200% for the 2018 plan and 250% for the 2019 and 2020 plans, based upon the Company’s total shareholder return relative to specified comparable groups over the performance period. The fair value of the performance units awarded during the years ended December 2020, 2019 and 2018 were calculated primarily using a Monte-Carlo simulation model with the following weighted-average assumptions: Weighted-average assumptions used: 2020 2019 2018 Annual dividend yield n/a 1.4 % 1.6 % Risk-free interest rate 1.4 % 2.4 % 2.3 % Annualized volatility 24.5 % 27.4 % 29.1 % Expected life (in years) 2.9 2.8 2.9 NOTE 4. Stock Plans and Share-Based Compensation, continued Performance unit grant and vesting information is summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 76.17 $ 66.18 $ 55.57 Fair value of units vested in fiscal year ending (in millions) $ 18 $ 17 $ 14 The performance unit activity related to the outstanding long-term incentive plans and corresponding fair value is summarized as follows: Performance Units Outstanding Weighted-Average Fair Value at Grant Date Unvested at December 31, 2019 643 $ 60.58 Granted 356 76.17 Forfeited (34) 66.71 Vested (325) 55.35 Unvested at December 31, 2020 640 $ 71.59 As of December 2020, there was $2 million of total unrecognized compensation cost related to performance units that is expected to be recognized over a weighted-average period of approximately one year. Stock Options Stock options in 2020, 2019, and 2018 were primarily granted along with the corresponding LTIP plans. Under this program, an employee receives an award that provides the opportunity in the future to purchase CSX shares at the closing market price of the stock on the date the award is granted (the strike price). Options granted in 2020 and 2019 become exercisable either in equal installments on the anniversary of the grant date over a vesting period (three-year graded) or three years after the grant date (three-year cliff), depending on the individual grant. The options granted in 2018 vest three years after the grant date (three-year cliff). All options expire 10 years from the grant date if they are not exercised. The fair value of stock options granted was estimated as of the dates of grant using the Black-Scholes option valuation model, which uses the following assumptions: dividend yield, risk-free interest rate, annualized volatility and expected life. The annual dividend yield is based on the most recent quarterly CSX dividend payment annualized. The risk-free interest rate is based on U.S. Treasury yield curve in effect at the time of grant. The annualized volatility is based on historical volatility of daily CSX stock price returns over a 6.0 year look-back period ending on the grant date. The expected life is calculated using the safe harbor approach due to lack of historical data on CSX options, which is the midpoint between the vesting schedule and contractual term (10 years). NOTE 4. Stock Plans and Share-Based Compensation, continued Assumptions and inputs used to estimate fair value of stock options are summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 18.94 $ 17.87 $ 14.65 Stock options valuation assumptions: Annual dividend yield 1.2 % 1.3 % 1.5 % Risk-free interest rate 1.4 % 2.4 % 2.6 % Annualized volatility 26.1 % 25.7 % 27.0 % Expected life (in years) 6.0 6.1 6.5 Other pricing model inputs: Weighted-average grant-date market price of CSX stock (strike price) $ 79.58 $ 70.01 $ 54.19 The stock option activity is summarized as follows: Stock Options Outstanding Weighted-Average Exercise Price Weighted-Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2019 3,795 $ 49.78 Granted 1,339 79.58 Forfeited (131) 72.04 Exercised (786) 37.41 Outstanding at December 31, 2020 4,217 $ 60.88 7.5 $ 126 Exercisable at December 31, 2020 1,257 $ 40.05 6.0 $ 64 Unrecognized compensation expense related to stock options as of December 2020 was $18 million and is expected to be recognized over a weighted-average period of approximately two years. The Company issues new shares upon stock option exercises. There were no significant exercises during 2018. Additional information on stock option exercises is summarized as follows: (Dollars in Millions) 2020 2019 Intrinsic value of stock options exercised $ 30 $ 87 Cash received from option exercises $ 29 $ 45 NOTE 4. Stock Plans and Share-Based Compensation, continued Restricted Stock Grants Restricted stock grants consist of units and awards, each equivalent to one share of CSX stock. Restricted stock units are primarily issued along with corresponding LTIP plans and vest three years after the date of grant. Separately, restricted stock awards generally vest over an employment period of up to five years. These awards are time-based and not based upon CSX’s attainment of operational targets. Participants receive cash or stock dividend equivalents on these shares, depending on the grant. Restricted stock grant and vesting information is summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 79.30 $ 69.19 $ 62.60 Fair value of units and awards vested during fiscal year ended (in millions) $ 8 $ 7 $ 9 The restricted stock activity related to the outstanding long-term incentive plans and other awards and corresponding fair value is summarized as follows: Restricted Stock Units and Awards Outstanding Weighted-Average Fair Value at Grant Date Unvested at December 31, 2019 427 $ 57.29 Granted 106 79.30 Forfeited (24) 63.12 Vested (157) 48.42 Unvested at December 31, 2020 352 $ 67.08 As of December 2020, unrecognized compensation expense for these restricted stock units and awards was approximately $9 million , which will be expensed over a weighted-average remaining period of two years. NOTE 4. Stock Plans and Share-Based Compensation, continued Stock Awards for Directors CSX’s non-management directors receive a base annual retainer of $112,500 to be paid quarterly in cash, unless the director chooses to defer the retainer in the form of cash or CSX common stock. Additionally, non-management directors receive an annual grant of common stock in the amount of approximately $162,500, with the number of shares to be granted based on the average closing price of CSX stock in the months of November, December and January. The independent non-executive Chairman also receives an annual grant of common stock in the amount of approximately $250,000, with the number of shares to be granted based on the average closing price of CSX stock in the months of November, December, and January. These awards are evaluated periodically by the Board of Directors. Employee Stock Purchase Plan In May 2018, shareholders approved the 2018 CSX Employee Stock Purchase Plan (“ESPP”) for the benefit of Company employees. The Company registered 4 million shares of common stock that may be issued pursuant to this plan. Under the ESPP, employees may contribute between 1% and 10% of base compensation, after-tax, to purchase up to $25,000 of market value CSX common stock per year at 85% of the closing market price on either the grant date or the last day of the six-month offering period, whichever is lower. During 2019 and 2020, the Company issued the following shares under this program. Fiscal Years 2020 2019 Shares issued (in thousands) 242 249 Weighted average purchase price per share $ 60.40 $ 52.72

Casualty, Environmental and Oth

Casualty, Environmental and Other Reserves	12 Months Ended
Casualty, Environmental and Other Reserves	Dec. 31, 2020
Casualty, Environmental and Other Reserves [Abstract]
Casualty, Environmental and Other Reserves	Casualty, Environmental and Other Reserves Activity related to casualty, environmental and other reserves is as follows: Casualty Environmental Other (Dollars in Millions) Reserves Reserves Reserves Total December 31, 2017 $ 228 $ 90 $ 56 $ 374 Charged to Expense 21 10 41 72 Payments (50) (20) (52) (122) December 31, 2018 199 80 45 324 Charged to Expense 56 17 34 107 Payments (68) (23) (35) (126) December 31, 2019 187 74 44 305 Charged to Expense 55 20 32 107 Payments (46) (18) (34) (98) December 31, 2020 $ 196 $ 76 $ 42 $ 314 NOTE 5. Casualty, Environmental and Other Reserves, continued Personal injury and environmental reserves are considered critical accounting estimates due to the need for management judgment. In the table above, the impacts of changes in estimates are included in the charged to expense amount and were not material in 2020, 2019, or 2018. Casualty, environmental and other reserves are provided for in the consolidated balance sheets as shown in the table below. December 2020 December 2019 (Dollars in Millions) Current Long-term Total Current Long-term Total Casualty: Personal Injury $ 38 $ 93 $ 131 $ 42 $ 87 $ 129 Occupational 11 54 65 6 52 58 Total Casualty $ 49 $ 147 $ 196 $ 48 $ 139 $ 187 Environmental 23 53 76 31 43 74 Other 18 24 42 21 23 44 Total $ 90 $ 224 $ 314 $ 100 $ 205 $ 305 These liabilities are accrued when probable and reasonably estimable in accordance with the Contingencies Topic in the ASC. Actual settlements and claims received could differ and final outcomes of these matters cannot be predicted with certainty. Considering the legal defenses currently available, the liabilities that have been recorded and other factors, it is the opinion of management that none of these items individually, when finally resolved, will have a material adverse effect on the Company's financial condition, results of operations or liquidity. Should a number of these items occur in the same period, however, their combined effect could be material in that particular period. Casualty Casualty reserves of $196 million and $187 million for 2020 and 2019, respectively, represent accruals for personal injury, occupational disease and occupational injury claims. The Company's self-insured retention amount for these claims is $75 million per occurrence. Currently, no individual claim is expected to exceed the self-insured retention amount. Most of the Company's casualty claims relate to CSXT. In accordance with the Contingencies Topic in the ASC, to the extent the value of an individual claim exceeds the self-insured retention amount, the Company would present the liability on a gross basis with a corresponding receivable for insurance recoveries. These reserves fluctuate based upon the timing of payments as well as changes in estimate. Actual results may vary from estimates due to the number, type and severity of the injury, costs of medical treatments and uncertainties in litigation. Defense and processing costs, which historically have been insignificant and are anticipated to be insignificant in the future, are not included in the recorded liabilities. Changes in casualty reserves are included in materials, supplies and other on the consolidated income statements. NOTE 5. Casualty, Environmental and Other Reserves, continued Personal Injury Personal injury reserves represent liabilities for employee work-related and third-party injuries. Work-related injuries for CSXT employees are primarily subject to the Federal Employers' Liability Act ("FELA"). CSXT retains an independent actuary to assist management in assessing the value of personal injury claims. An analysis is performed by the actuary quarterly and is reviewed by management. The methodology used by the actuary includes a development factor to reflect growth or reduction in the value of these personal injury claims based largely on CSXT's historical claims and settlement experience. These analyses did not result in a material adjustment to the personal injury reserve in 2020, 2019 or 2018. Occupational Occupational reserves represent liabilities arising from allegations of exposure to certain materials in the workplace (such as solvents, soaps, chemicals and diesel fumes), past exposure to asbestos or allegations of chronic physical injuries resulting from work conditions (such as repetitive stress injuries). Beginning in second quarter 2020, the Company retains an independent actuary to analyze the Company’s historical claim filings, settlement amounts, and dismissal rates to assist in determining future anticipated claim filing rates and average settlement values. This analysis is performed by the actuary and reviewed by management quarterly. Previously, the quarterly analysis was performed by management. There were no material adjustments to the occupational reserve in 2020, 2019 or 2018. Environmental Environmental reserves were $76 million and $74 million for 2020 and 2019, respectively. The Company is a party to various proceedings related to environmental issues, including administrative and judicial proceedings involving private parties and regulatory agencies. The Company has been identified as a potentially responsible party at approximately 220 environmentally impaired sites. Many of these are, or may be, subject to remedial action under the federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 ("CERCLA"), also known as the Superfund Law, or similar state statutes. Most of these proceedings arose from environmental conditions on properties used for ongoing or discontinued railroad operations. A number of these proceedings, however, are based on allegations that the Company, or its predecessors, sent hazardous substances to facilities owned or operated by others for treatment, recycling or disposal. In addition, some of the Company’s land holdings were leased to others for commercial or industrial uses that may have resulted in releases of hazardous substances or other regulated materials onto the property and could give rise to proceedings against the Company. In any such proceedings, the Company is subject to environmental clean-up and enforcement actions under the Superfund Law, as well as similar state laws that may impose joint and several liability for clean-up and enforcement costs on current and former owners and operators of a site without regard to fault or the legality of the original conduct. These costs could be substantial. NOTE 5. Casualty, Environmental and Other Reserves, continued In accordance with the Asset Retirement and Environmental Obligations Topic in the ASC, the Company reviews its role with respect to each site identified at least quarterly, giving consideration to a number of factors such as: • type of clean-up required; • nature of the Company’s alleged connection to the location (e.g., generator of waste sent to the site or owner or operator of the site); • extent of the Company’s alleged connection (e.g., volume of waste sent to the location and other relevant factors); and • number, connection and financial viability of other named and unnamed potentially responsible parties at the location. Based on management's review process, amounts have been recorded to cover contingent anticipated future environmental remediation costs with respect to each site to the extent such costs are reasonably estimable and probable. The recorded liabilities for estimated future environmental costs are undiscounted. The liability includes future costs for remediation and restoration of sites as well as any significant ongoing monitoring costs, but excludes any anticipated insurance recoveries. Payments related to these liabilities are expected to be made over the next several years. Environmental remediation costs are included in materials, supplies and other on the consolidated income statements. Currently, the Company does not possess sufficient information to reasonably estimate the amounts of additional liabilities, if any, on some sites until completion of future environmental studies. In addition, conditions that are currently unknown could, at any given location, result in additional exposure, the amount and materiality of which cannot presently be reasonably estimated. Based upon information currently available, however, the Company believes its environmental reserves accurately reflect the estimated cost of remedial actions currently required. Other Other reserves were $42 million and $44 million for 2020 and 2019, respectively. These reserves include liabilities for various claims, such as property, automobile and general liability. Also included in other reserves are longshoremen disability claims related to a previously owned international shipping business (these claims are in runoff) as well as claims for current port employees.

Properties

Properties	12 Months Ended
Properties	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Properties	Properties Details of the Company’s net properties are as follows: (Dollars in Millions) Accumulated Net Book Annual Depreciation Estimated Useful Life Depreciation December 2020 Cost Depreciation Value Rate ( Avg. Years) Method Road Rail and Other Track Material $ 8,449 $ (1,739) $ 6,710 2.5% 41 Group Life Ties 6,284 (1,780) 4,504 3.5% 28 Group Life Grading 2,768 (614) 2,154 1.3% 75 Group Life Ballast 3,238 (1,051) 2,187 2.6% 38 Group Life Bridges, Trestles, and Culverts 2,688 (380) 2,308 1.7% 60 Group Life Signals and Interlockers 3,170 (944) 2,226 4.1% 24 Group Life/ Straight Line (a) Buildings 1,366 (529) 837 2.5% 40 Group Life Other 5,146 (2,101) 3,045 4.1% 25 Group Life Total Road 33,109 (9,138) 23,971 Equipment Locomotive 5,085 (1,849) 3,236 3.6% 27 Group Life Freight Cars 2,557 (540) 2,017 2.9% 35 Group Life Work Equipment and Other 2,585 (1,559) 1,026 8.2% 12 Group Life/ Straight Line (a) Total Equipment 10,227 (3,948) 6,279 Land 1,823 — 1,823 N/A N/A N/A Construction In Progress 371 — 371 N/A N/A N/A Total Properties $ 45,530 $ (13,086) $ 32,444 (a) For depreciation method, certain asset categories contain intermodal terminals or technology-related assets, which are depreciated using the straight-line method. NOTE 6. Properties, continued (Dollars in Millions) Accumulated Net Book Annual Depreciation Estimated Useful Life Depreciation December 2019 Cost Depreciation Value Rate (Avg. Years) Method Road Rail and Other Track Material $ 8,194 $ (1,719) $ 6,475 2.5% 40 Group Life Ties 6,041 (1,666) 4,375 3.7% 27 Group Life Grading 2,763 (595) 2,168 1.4% 72 Group Life Ballast 3,156 (1,013) 2,143 2.7% 37 Group Life Bridges, Trestles, and Culverts 2,529 (334) 2,195 1.6% 61 Group Life Signals and Interlockers 3,077 (819) 2,258 4.0% 25 Group Life/ Straight Line (a) Buildings 1,335 (492) 843 2.5% 40 Group Life Other 5,030 (1,980) 3,050 4.2% 24 Group Life Total Road 32,125 (8,618) 23,507 Equipment Locomotive 5,320 (2,020) 3,300 3.6% 27 Group Life Freight Cars 2,964 (880) 2,084 2.9% 35 Group Life Work Equipment and Other 2,424 (1,414) 1,010 8.2% 12 Group Life/ Straight Line (a) Total Equipment 10,708 (4,314) 6,394 Land 1,836 — 1,836 N/A N/A N/A Construction In Progress 431 — 431 N/A N/A N/A Total Properties $ 45,100 $ (12,932) $ 32,168 (a) For depreciation method, certain asset categories contain intermodal terminals or technology-related assets, which are depreciated using the straight-line method. NOTE 6. Properties, continued Capital Expenditures The Company’s capital investment includes purchased and self-constructed assets and property additions that substantially extend the service life or increase the utility of those assets. Indirect costs that can be specifically traced to capital projects are also capitalized. The Company is committed to maintaining and improving its existing infrastructure and expanding its network capacity for long-term growth. Rail operations are capital intensive and CSX accounts for these costs in accordance with GAAP and the Company’s capitalization policy. All properties are stated at historical cost less an allowance for accumulated depreciation. The Company’s largest category of capital investment is the replacement of track assets and the acquisition or construction of new assets that enable CSX to enhance its operations or provide new capacity offerings to its customers. These construction projects are primarily completed by CSXT employees. Costs for track asset replacement and capacity projects that are capitalized include: • labor costs, because many of the assets are self-constructed; • costs to purchase or construct new track or to prepare ground for the laying of track; • welding (rail, field and plant), which are processes used to connect segments of rail; • new ballast, which is gravel and crushed stone that holds track in line; • fuels and lubricants associated with tie, rail and surfacing work, which is the process of raising track to a designated elevation over an extended distance; • cross, switch and bridge ties, which are the braces that support the rails on a track; • gauging, which is the process of standardizing the distance between rails; • handling costs associated with installing rail, ties or ballast; • usage charge of machinery and equipment utilized in construction or installation; and • other track materials. Labor is a significant cost in self-constructed track replacement work. CSXT engineering employees directly charge their labor to the track replacement project (the capitalized depreciable property). In replacing track, these employees concurrently perform deconstruction and installation of track material. Because of this concurrent process, CSX must estimate the amount of labor that is related to deconstruction versus installation. As a component of the depreciation study for road and track assets, management performs an analysis of labor costs related to the self-constructed track replacement work, which includes direct observation of track replacement processes. Through this analysis, CSX determined that approximately 20% of labor costs associated with track replacement is related to the deconstruction of old track, for which certain elements are expensed, and 80% is associated with the installation of new track, which is capitalized. Capital investment related to locomotives and freight cars comprises the second largest category of the Company’s capital assets. This category includes purchases of locomotives and freight cars as well as certain equipment leases that are considered to be finance leases in accordance with the Leases Topic in the ASC. In addition, costs to modify or rebuild these assets are capitalized if the investment incurred extends the asset’s service life or improves utilization. Improvement projects must meet specified dollar thresholds to be capitalized and are reviewed by management to determine proper accounting treatment. Routine repairs, overhauls and other maintenance costs, for all asset categories, are expensed as incurred. NOTE 6. Properties, continued Depreciation Method The depreciable assets of the Company are depreciated using either the group-life or straight-line method of accounting, which are both acceptable depreciation methods in accordance with GAAP. The Company depreciates its railroad assets, including main-line track, locomotives and freight cars, using the group-life method. Assets depreciated under the group-life method comprise 87% of total fixed assets of $45.5 billion on a gross basis as of December 2020. The remaining depreciable assets of the Company, including non-railroad assets and assets under finance leases, are depreciated using the straight-line method on a per asset basis. Land is not depreciated. The group-life method aggregates assets with similar lives and characteristics into groups and depreciates each of these groups as a whole. When using the group-life method, an underlying assumption is that each group of assets, as a whole, is used and depreciated to the end of its group’s recoverable life. The Company currently utilizes different depreciable asset categories to account for depreciation expense for the railroad assets that are depreciated under the group-life method. By utilizing various depreciable categories, the Company can more accurately account for the use of its assets. All assets of the Company are depreciated on a time or life basis. The group-life method of depreciation closely approximates the straight-line method of depreciation. Additionally, due to the nature of most of its assets (e.g. track is one contiguous, connected asset), the Company believes that this is the most accurate and effective way to properly depreciate its assets. Estimated Useful Life Management performs a review of depreciation expense and useful lives on a regular basis. Under the group-life method, the service lives and salvage values for each group of assets are determined by completing periodic depreciation studies and applying management’s methods to determine the service lives of its properties. A depreciation study is the periodic review of asset service lives, salvage values, accumulated depreciation, and other related factors for group assets conducted by a third-party specialist, analyzed by the Company’s management and approved by the STB, the regulatory board that has broad jurisdiction over railroad practices. The STB requires depreciation studies be performed every three years for equipment assets (e.g., locomotives and freight cars) and every six years for road and track assets (e.g., bridges, signals, rail, ties, and ballast). The Company believes the frequency of depreciation studies currently required by the STB, complemented by annual data reviews conducted by a third-party specialist and analyzed by the Company's management, provides adequate review of asset service lives and that a more frequent review would not result in a material change due to the long-lived nature of most of the assets. The Company completed a depreciation study for its road and track assets in 2020 and for equipment assets in 2019, both of which resulted in changes to accumulated depreciation, service lives, salvage values, and other related factors for certain assets. Recent experience with depreciation studies has resulted in changes to accumulated depreciation and depreciation rates that did not materially affect the Company's depreciation expense of $1.4 billion, $1.3 billion and $1.3 billion for 2020, 2019 and 2018, respectively. NOTE 6. Properties, continued Group-Life Assets Sales and Retirements Since the rail network is one contiguous, connected network it is impractical to maintain specific identification records for these assets. For track assets (e.g., rail, ties, and ballast), CSX utilizes a first-in, first-out approach to asset retirements. Equipment assets (e.g., locomotives and freight cars) are specifically identified at retirement. When an equipment asset is retired that has been depreciated using the group-life method, the cost is reduced from the cost base and recorded in accumulated depreciation. For sales or retirements of assets depreciated under the group-life method that occur in the ordinary course of business, the asset cost (net of salvage value or sales proceeds) is charged to accumulated depreciation and no gain or loss is immediately recognized. This practice is consistent with accounting treatment prescribed under the group-life method. As part of the depreciation study, an assessment of the recorded amount of accumulated depreciation is made to determine if it is deficient (or in excess) of the appropriate amount indicated by the study. Any such deficiency (or excess), including any deferred gains or losses, is amortized as a component of depreciation expense over the remaining service life of the asset group until the next required depreciation study. Since the overall assumption with the group-life method is that the assets within the group on average have the same service life and characteristics, it is therefore concluded that the deferred gains and losses offset over time. For sales or retirements of assets depreciated under the group-life method that do not occur in the ordinary course of business, a gain or loss may be recognized if the sale or retirement meets each of the following three criteria: (i) it is unusual, (ii) it is material in amount, and (iii) it varies significantly from the retirement profile identified through our depreciation studies. No material gains or losses were recognized on the sale of assets depreciated using the group-life method in 2020, 2019, or 2018 as no sales met the criteria described above. Land and Straight-line Assets Sales and Retirements When the Company sells or retires land, land-related easements or assets depreciated under the straight-line method, a gain or loss is recognized in materials, supplies and other on the consolidated statements of income. Primarily as a result of its initiative to monetize non-core properties, the Company recognized gains on the sale of properties of $35 million, $151 million and $154 million in 2020, 2019 and 2018, respectively. Impairment Review Properties and other long-lived assets are reviewed for impairment whenever events or business conditions indicate the carrying amount of such assets may not be fully recoverable. Initial assessments of recoverability are based on estimates of undiscounted future net cash flows associated with an asset or a group of assets in accordance with the Property, Plant, and Equipment Topic in the ASC. Where impairment is indicated, the assets are evaluated and their carrying amount is reduced to fair value based on discounted net cash flows or other estimates of fair value. Impairment expense of $8 million in 2020 and $24 million in 2018 was primarily due to the discontinuation of certain in-progress projects. In 2019, impairment expense of $22 million was related to an intermodal terminal sale agreement. Impairment expense is recorded in materials, supplies and other expense on the consolidated income statement.

Leases

Leases	12 Months Ended
Leases	Dec. 31, 2020
Leases [Abstract]
Leases	Leases At inception, the Company determines if an arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. Some of the Company’s lease arrangements contain lease components (e.g., minimum rent payments) and non-lease components (e.g., maintenance, labor charges, etc.). The Company generally accounts for each component separately based on the estimated standalone price of each component. For certain equipment leases, such as freight car, vehicles and work equipment, the Company accounts for the lease and non-lease components as a single lease component. Certain of the Company’s lease agreements include rental payments that are adjusted periodically for an index or rate. The leases are initially measured using the projected payments adjusted for the index or rate in effect at the commencement date. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. Operating Leases Operating leases are included in right-of-use lease assets, other current liabilities and long-term lease liabilities on the consolidated balance sheets. These assets and liabilities are recognized at the commencement date based on the present value of remaining lease payments over the lease term using the Company’s secured incremental borrowing rates or implicit rates, when readily determinable. Short-term operating leases, which have an initial term of 12 months or less, are not recorded on the balance sheet. The Company has various lease agreements with other parties with terms up to 50 years. Non-cancelable, long-term leases may include provisions for maintenance, options to purchase and options to extend the terms. These options are included in the lease term when it is reasonably certain that the option will be exercised. Lease expense for operating leases, including leases with escalations over their terms, is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. Lease expense is included in equipment and other rents on the consolidated income statements and is reported net of lease income. Lease income was not material to the results of operations for 2020, 2019 or 2018. NOTE 7. Leases, continued CSX has a significant operating lease with the State of Georgia for approximately 137 miles of right-of-way with integral equipment for a term of 50 years with an annual 2.5% increase. The following table presents information about the amount, timing and uncertainty of cash flows arising from all of the Company’s operating leases as of December 31, 2020 . (Dollars in Millions) December 2020 Maturity of Lease Liabilities Lease Payments 2021 47 2022 43 2023 36 2024 36 2025 35 Thereafter 1,172 Total undiscounted operating lease payments $ 1,369 Less: Imputed interest (869) Present value of operating lease liabilities $ 500 (Dollars in Millions) 2020 2019 Balance Sheet Classification Right of use asset $ 472 $ 532 Current lease liabilities (recorded in other current liabilities) $ 45 $ 57 Long-term lease liabilities 455 493 Total operating lease liabilities $ 500 $ 550 Other Information Weighted-average remaining lease term for operating leases 35 years 33 years Weighted-average discount rate for operating leases 5.0 % 5.0 % Cash Flows As of December 2020 and 2019, the Company's right-of-use asset was valued at $472 million and $532 million, respectively. An initial asset of $534 million was recognized as a non-cash asset addition upon adoption of the new lease accounting standard effective January 1, 2019. Additional right-of-use assets of $11 million and $51 million were recognized as non-cash asset additions that resulted from new operating lease liabilities during the years ended 2020 and 2019, respectively. Cash paid for amounts included in the present value of operating lease liabilities was $59 million and $60 million during the years ended 2020 and 2019, respectively, and is included in operating cash flows. Operating Lease Costs These costs are primarily related to long-term operating leases, but also include immaterial amounts for variable leases and short-term leases with terms greater than 30 days. These amounts are shown in the table below. Fiscal Years (Dollars in Millions) 2020 2019 2018 Rent Expense on Operating Leases $ 82 $ 84 $ 66 NOTE 7. Leases, continued Finance Leases Finance leases are included in properties - net and long-term debt on the consolidated balance sheets and were not material as of December 2020 or December 2019. The associated amortization expense and interest expense are included in depreciation and interest expense, respectively, on the consolidated income statements and were not material to the results of operations for 2020, 2019 or 2018.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
Commitments and Contingencies	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Purchase Commitments CSXT's long-term locomotive maintenance program agreement with a third party contains commitments related to specific locomotive rebuilds and a long-term maintenance program that covers a portion of CSXT’s fleet of locomotives. The maintenance program costs are based on the maintenance cycle for each covered locomotive, which is determined by the asset's age and type. Expected future costs may change as required maintenance schedules are revised and locomotives are placed into or removed from service. Under CSXT’s current obligations, the agreement will expire no earlier than 2035. The following table summarizes the number of locomotives covered and CSXT’s payments under the long-term maintenance program. Fiscal Years (Dollars in Millions) 2020 2019 2018 Amounts Paid $ 158 $ 139 $ 170 Number of Locomotives 1,874 1,897 1,910 The total of annual payments under the agreement, including those related to locomotive rebuilds and the long-term locomotive maintenance program, are estimated in the table below. Additionally, the Company has various other commitments to purchase technology, communications, railcar maintenance and other services from various suppliers. Total annual payments under all of these purchase commitments are also estimated in the table below. (Dollars in Millions) Locomotive Maintenance & Rebuild Payments Other Total 2021 $ 195 $ 39 $ 234 2022 204 22 226 2023 228 20 248 2024 270 14 284 2025 284 14 298 Thereafter 1,892 93 1,985 Total $ 3,073 $ 202 $ 3,275 NOTE 8. Commitments and Contingencies, continued Insurance The Company maintains insurance programs with substantial limits for property damage, including resulting business interruption, and third-party liability. A certain amount of risk is retained by the Company on each insurance program. During 2020, the Company restructured its property insurance program to increase the level at which the Company retains all risk from $50 million to $100 million per occurrence for losses from floods and named windstorms from $25 million to $75 million per occurrence for other property losses. For third-party liability claims, the Company retains all risk up to $75 million per occurrence. As CSX negotiates insurance coverage above its full self-retention amounts, it retains a percentage of risk at various layers of coverage. While the Company believes its insurance coverage is adequate, future claims could exceed existing insurance coverage or insurance may not continue to be available at commercially reasonable rates. Legal The Company is involved in litigation incidental to its business and is a party to a number of legal actions and claims, various governmental proceedings and private civil lawsuits, including, but not limited to, those related to fuel surcharge practices, tax matters, environmental and hazardous material exposure matters, FELA and labor claims by current or former employees, other personal injury or property claims and disputes and complaints involving certain transportation rates and charges. Some of the legal proceedings include claims for compensatory as well as punitive damages and others are, or are purported to be, class actions. While the final outcome of these matters cannot be predicted with certainty, considering, among other things, the legal defenses available and liabilities that have been recorded along with applicable insurance, it is currently the opinion of management that none of these pending items will have a material adverse effect on the Company's financial condition, results of operations or liquidity. An unexpected adverse resolution of one or more of these items, however, could have a material adverse effect on the Company's financial condition, results of operations or liquidity in that particular period. The Company is able to estimate a range of possible loss for certain legal proceedings for which a loss is reasonably possible in excess of reserves established. The Company has estimated this range to be $1 million to $24 million in aggregate as of December 31, 2020. This estimated aggregate range is based upon currently available information and is subject to significant judgment and a variety of assumptions. Accordingly, the Company's estimate will change from time to time, and actual losses may vary significantly from the current estimate. Fuel Surcharge Antitrust Litigation In May 2007, class action lawsuits were filed against CSXT and three other U.S.-based Class I railroads alleging that the defendants' fuel surcharge practices relating to contract and unregulated traffic resulted from an illegal conspiracy in violation of antitrust laws. The class action lawsuits were consolidated into one case in federal court in the District of Columbia. In 2017, the District Court issued its decision denying class certification. On August 16, 2019, the U.S. Court of Appeals for the D.C. Circuit affirmed the District Court’s ruling. The consolidated case is now moving forward without class certification. Although a class was not certified, shippers other than those who brought the original lawsuit in 2007 must decide whether to bring their own individual claim against one or more railroads. Individual shipper claims filed to date have been consolidated into a separate case. NOTE 8. Commitments and Contingencies, continued CSXT believes that its fuel surcharge practices were arrived at and applied lawfully and that the case is without merit. Accordingly, the Company intends to defend itself vigorously. However, penalties for violating antitrust laws can be severe, and resolution of these matters individually or when aggregated could have a material adverse effect on the Company's financial condition, results of operations or liquidity in that particular period. Environmental CSXT is indemnifying Pharmacia LLC, formerly known as Monsanto Company, ("Pharmacia") for certain liabilities associated with real estate located in Kearny, New Jersey along the Lower Passaic River (the “Property”). The Property, which was formerly owned by Pharmacia, is now owned by CSXT. CSXT's indemnification and defense duties arise with respect to several matters. The U.S. Environmental Protection Agency ("EPA"), using its CERCLA authority, seeks the investigation and cleanup of hazardous substances in the 17-mile Lower Passaic River Study Area (the "Study Area”). CSXT, on behalf of Pharmacia, and a significant number of other potentially responsible parties are together conducting a Remedial Investigation and Feasibility Study of the Study Area pursuant to an Administrative Settlement Agreement and Order on Consent with the EPA. Pharmacia’s share of responsibility, indemnified by CSXT, for the investigation and cleanup costs of the Study Area may be determined through various mechanisms including (a) an allocation and settlement with EPA; (b) litigation brought by EPA against non-settling parties; or (c) litigation among the responsible parties. In March 2016, EPA issued its Record of Decision detailing the agency’s mandated remedial process for the lower 8 miles of the Study Area. Approximately 80 parties, including Pharmacia, are participating in an EPA-directed allocation and settlement process to assign responsibility for the remedy selected for the lower 8 miles of the Study Area. CSXT is participating in the EPA-directed allocation and settlement process on behalf of Pharmacia. At a later date, EPA will select a remedy for the remainder of the Study Area and is expected to again seek the participation of private parties to implement the selected remedy using EPA’s CERCLA authority to compel such participation, if necessary. CSXT is also defending and indemnifying Pharmacia with regard to the Property in litigation filed by Occidental Chemical Corporation, which is seeking to recover various costs. These costs include costs for the remedial design of the lower 8 miles of the Study Area, as well as anticipated costs associated with the future remediation of the lower 8 miles of the Study Area and potentially the entire Study Area. Alternatively, Occidental seeks to compel some, or all of the defendants to participate in the remediation of the Study Area. Pharmacia is one of approximately 110 defendants in this federal lawsuit filed by Occidental on June 30, 2018.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
Employee Benefit Plans	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Employee Benefit Plans	Employee Benefit Plans The Company sponsors defined benefit pension plans principally for salaried, management personnel. For employees hired prior to 2003, the plans provide eligible employees with retirement benefits based predominantly on years of service and compensation rates near retirement. For employees hired between 2003 and 2019, benefits are determined based on a cash balance formula, which provides benefits by utilizing interest and pay credits based upon age, service and compensation. Beginning in 2020, the CSX Pension Plan was closed to new participants. In addition to these plans, the Company sponsors a post-retirement medical plan and a life insurance plan that provide certain benefits to full-time, salaried, management employees hired prior to 2003 upon their retirement if certain eligibility requirements are met. Changes to the post-retirement medical and life insurance plans were communicated to participants in October 2018. Beginning in 2019, both the life insurance benefit for eligible active employees and health savings account contributions made by the Company to eligible retirees younger than 65 were eliminated. Beginning in 2020, the employer-funded health reimbursement arrangements for eligible retirees 65 years or older were eliminated. As a result of these plan amendments, the Company recognized a decrease of $102 million in the post-retirement benefit liability and a corresponding gain in other comprehensive income in 2018. These changes did not result in a curtailment loss as there was no material impact to service costs for active plan participants. The Company engages independent actuaries to compute the amounts of liabilities and expenses relating to these plans subject to the assumptions that the Company determines are appropriate based on historical trends, current market rates and future projections. These amounts are reviewed by management. In order to perform this valuation, the actuaries are provided with the details of the population covered at the beginning of the year, summarized in the table below, and projects that population forward to the end of the year . Summary of Participants as of January 1, 2020 Pension Plans Post-retirement Medical Plan Active Employees 3,373 779 Retirees and Beneficiaries 11,841 2,282 Other (a) 3,854 — Total 19,068 3,061 (a) For pension plans, the other category consists mostly of terminated but vested former employees. NOTE 9. Employee Benefit Plans, continued The benefit obligation for these plans represents the liability of the Company for current and retired employees and is affected primarily by the following: • service cost (benefits attributed to employee service during the period); • interest cost (interest on the liability due to the passage of time); • actuarial gains/losses (experience during the year different from that assumed and changes in plan assumptions); and • benefits paid to participants. Cash Flows Plan assets are amounts that have been segregated and restricted to provide qualified pension plan benefits and include amounts contributed by the Company and amounts earned from invested contributions, net of benefits paid. Qualified pension plan obligations are funded in accordance with regulatory requirements and with an objective of meeting or exceeding minimum funding requirements necessary to avoid restrictions on flexibility of plan operation and benefit payments. The Company funds the cost of the post-retirement medical and life insurance benefits as well as nonqualified pension benefits on a pay-as-you-go basis. No qualified pension plan contributions were made during 2020, 2019 and 2018. No contributions to the Company's qualified pension plans are expected in 2021. Future expected benefit payments are as follows: Expected Cash Flows (Dollars in Millions) Pension Benefits Post-retirement Benefits 2021 $ 196 $ 17 2022 188 10 2023 187 9 2024 186 8 2025 185 8 2026-2030 898 28 Total $ 1,840 $ 80 Plan Assets During 2020, the Company migrated to an outsourced investment management strategy to manage the pension plan assets. The CSX Investment Committee (the “Investment Committee”), whose members are selected by the Executive Vice President and Chief Financial Officer, is responsible for setting policy and oversight of investment management. The Investment Committee and investment manager utilize an investment asset allocation strategy that is monitored on an ongoing basis and updated periodically in consideration of plan or employee changes, or changing market conditions. Periodic studies provide an extensive modeling of asset investment return in conjunction with projected plan liabilities and seek to evaluate how to maximize return within the constraints of acceptable risk. NOTE 9. Employee Benefit Plans, continued The current asset allocation targets 60% growth-oriented investments and 40% immunizing investments. The growth-oriented portfolio consists of return-seeking investments that are diversified across geography, market capitalization, and asset class. The immunizing portfolio is comprised of a customized mix of fixed income and cash investments designed to reduce liability risk. Allocations are evaluated for levels within 5% of targeted allocations and are adjusted quarterly as necessary. The distribution of pension plan assets as of the measurement date is shown in the table below, and these assets are reported net of pension liabilities on the balance sheet. December 2020 December 2019 Percent of Percent of (Dollars in Millions) Amount Total Assets Amount Total Assets Growth-Oriented $ 1,816 61 % $ 2,027 72 % Equity 1,324 44 1,772 63 Fixed Income 271 9 229 8 Cash and Cash Equivalents 221 8 26 1 Immunizing 1,184 39 798 28 Fixed Income 1,018 34 595 21 Cash and Cash Equivalents 166 5 203 7 Total $ 3,000 100 % $ 2,825 100 % Under the supervision of the Investment Committee, the investment manager selects investments or fund managers in accordance with standards of prudence applicable to asset diversification and investment suitability. The Company also selects fund managers with differing investment styles and benchmarks their investment returns against appropriate indices. Fund investment performance is continuously monitored. Acceptable performance is determined in the context of the long-term return objectives of the fund and appropriate asset class benchmarks. Within the Company's equity funds, domestic stock is diversified among large and small capitalization stocks. International stock is diversified in a similar manner as well as in developed versus emerging markets stocks. Guidelines established with individual managers limit investment by industry sectors, individual stock issuer concentration and the use of derivatives and CSX securities. Fixed income securities guidelines established with individual managers specify the types of allowable investments, such as government, corporate and asset-backed bonds, target certain allocation ranges for domestic and foreign investments and limit the use of certain derivatives. Additionally, guidelines stipulate minimum credit quality constraints and any prohibited securities. For detailed information regarding the fair value of pension assets, see Note 13, Fair Value Measurements . NOTE 9. Employee Benefit Plans, continued Benefit Obligation, Plan Assets and Funded Status Changes in benefit obligation and the fair value of plan assets for the 2020 and 2019 calendar plan years are as follows: Pension Benefits Post-retirement Benefits Plan Year Plan Year Plan Year Plan Year (Dollars in Millions) 2020 2019 2020 2019 Actuarial Present Value of Benefit Obligation Accumulated Benefit Obligation $ 3,134 $ 2,963 N/A N/A Projected Benefit Obligation 3,257 3,122 $ 96 $ 117 Change in Projected Benefit Obligation: Projected Benefit Obligation at Beginning of Plan Year $ 3,122 $ 2,758 $ 117 $ 118 Service Cost (a) 46 34 1 1 Interest Cost 82 103 5 2 Plan Participants' Contributions — — 6 7 Actuarial Loss (Gain) 197 418 (11) 22 Benefits Paid (190) (191) (22) (33) Benefit Obligation at End of Plan Year $ 3,257 $ 3,122 $ 96 $ 117 Change in Plan Assets: Fair Value of Plan Assets at Beginning of Plan Year $ 2,825 $ 2,431 $ — $ — Actual Return on Plan Assets 345 568 — — Non-qualified Employer Contributions 20 17 16 26 Plan Participants' Contributions — — 6 7 Benefits Paid (190) (191) (22) (33) Fair Value of Plan Assets at End of Plan Year 3,000 2,825 — — Funded Status at End of Plan Year $ (257) $ (297) $ (96) $ (117) (a) Service cost for each 2020 and 2019 includes capitalized service costs of $3 million. The $197 million net actuarial loss for pension benefits in 2020 was driven by a 70 bps decrease in the weighted average discount rate, partially offset by changes to assumptions based on census data. The $11 million net actuarial gain for post-retirement benefits in 2020 was driven by favorable participant experience and changes to assumptions based on census data. In 2019, the $418 million net actuarial loss for pension benefits and the $22 million net actuarial loss for post-retirement benefits were driven by a 111 bps decrease in the weighted average discount rate. NOTE 9. Employee Benefit Plans, continued For qualified plan funding purposes, assets and discounted liabilities are measured in accordance with the Employee Retirement Income Security Act ("ERISA"), as well as other related provisions of the Internal Revenue Code and related regulations. Under these funding provisions and the alternative measurements available thereunder, the Company estimates its unfunded obligation for qualified plans on an annual basis. In accordance with Compensation-Retirement Benefits Topic in the ASC, an employer must recognize the funded status of a pension or other post-retirement benefit plan by recording a liability (underfunded plan) or asset (overfunded plan) for the difference between the projected benefit obligation (or the accumulated post-retirement benefit obligation for a post-retirement benefit plan) and the fair value of plan assets at the plan measurement date. Amounts related to pension and post-retirement benefits recorded in other long-term assets, labor and fringe benefits payable and other long-term liabilities on the balance sheet are as follows: Pension Benefits Post-retirement Benefits December December December December (Dollars in Millions) 2020 2019 2020 2019 Amounts Recorded in Consolidated Balance Sheets: Long-term Assets (a) $ 29 $ 25 $ — $ — Current Liabilities (16) (17) (17) (20) Long-term Liabilities (270) (305) (79) (97) Net Amount Recognized in Consolidated Balance Sheets $ (257) $ (297) $ (96) $ (117) (a) Long-term assets as of December 2020 and 2019 relate to qualified pension plans where assets exceed projected benefit obligations. The funded status, or amount by which the benefit obligation exceeds the fair value of plan assets, represents a liability. At December 2020, the status of CSX plans with a net liability only is disclosed below. The total fair value of all plan assets as of December 2020 was $3.0 billion, which includes the qualified pension plans with net assets. Aggregate (Dollars in Millions) Fair Value Aggregate Benefit Obligations in Excess of Plan Assets of Plan Assets Benefit Obligation Projected Benefit Obligation $ 2,884 $ (3,170) Accumulated Benefit Obligation 2,884 (264) NOTE 9. Employee Benefit Plans, continued Net Benefit Expense Only the service cost component of net periodic benefit costs is included in labor and fringe expense on the consolidated income statement. All other components of net periodic benefit cost are included in other income - net. The following table describes the components of expense/(income) related to net benefit expense recorded on the income statement. Pension Benefits Post-retirement Benefits (Dollars in Millions) 2020 2019 2018 2020 2019 2018 Service Cost Included in Labor and Fringe $ 43 $ 31 $ 32 $ 1 $ 1 $ 2 Interest Cost 82 103 92 5 2 7 Expected Return on Plan Assets (176) (171) (176) — — — Amortization of Net Loss 54 30 41 1 — — Amortization of Prior Service Cost — — — (7) (7) (2) Total (Income)/ Expense Included in Other Income - Net (40) (38) (43) (1) (5) 5 Net Periodic Benefit Cost/(Credit) $ 3 $ (7) $ (11) $ — $ (4) $ 7 Settlement Gain (1) — (1) — — — Total Periodic Benefit Cost/(Credit) $ 2 $ (7) $ (12) $ — $ (4) $ 7 Pension and Other Post-retirement Benefits Adjustments The following table shows the pre-tax change in other comprehensive loss (income) attributable to certain components of net benefit expense and the change in benefit obligation for CSX for pension and other post-employment benefits. (Dollars in Millions) Pension Benefits Post-retirement Benefits Components of Other Comprehensive December December December December Loss (Income) 2020 2019 2020 2019 Recognized in the Balance Sheet Losses (Gains) $ 28 $ 21 $ (11) $ 22 Expense (Income) Recognized in the Income Statement Amortization of Net Losses $ 54 $ 30 $ 1 $ — Settlement Gain (1) — — — Amortization of Prior Service Costs — — (7) (7) As of December 2020, the balances to be amortized related to the Company's pension obligations is a pre-tax loss of $854 million and related to post-retirement obligations is a pre-tax gain of $78 million. These amounts are included in accumulated other comprehensive loss, a component of shareholders’ equity. NOTE 9. Employee Benefit Plans, continued Assumptions The expected long-term average rate of return on plan assets reflects the average rate of earnings expected on the funds invested, or to be invested, to provide for benefits included in the projected benefit obligation. In estimating that rate, the Company gives appropriate consideration to the returns being earned by the plan assets in the funds and the rates of return expected to be available for reinvestment as well as the current and projected asset mix of the funds. Management, with the assistance of the outsourced investment manager, balances market expectations obtained from various investment managers with both market and actual plan historical returns to develop a reasonable estimate of the expected long-term rate of return on assets. This assumption is reviewed annually and adjusted as deemed appropriate. The Company measures the service cost and interest cost components of the net pension and post-retirement benefits expense by using individual spot rates matched with separate cash flows for each future year. The weighted averages of assumptions used by the Company to value its pension and post-retirement obligations were as follows: Pension Benefits Post-retirement Benefits 2020 2019 2020 2019 Expected Long-term Return on Plan Assets: Benefit Cost for Current Plan Year 6.75 % 6.75 % N/A N/A Benefit Cost for Subsequent Plan Year 6.75 % 6.75 % N/A N/A Discount Rates: Benefit Cost for Plan Year Service Cost for Plan Year 3.32 % 4.40 % 2.93 % 4.14 % Interest Cost for Plan Year 2.69 % 3.87 % 2.43 % 3.51 % Benefit Obligation at End of Plan Year 2.43 % 3.13 % 2.07 % 2.87 % Salary Scale Inflation 4.60 % 4.60 % N/A N/A Cash Balance Plan Interest Credit Rate 3.75 % 3.75 % N/A N/A Other Plans Under collective bargaining agreements, the Company participates in a multi-employer benefit plan, which provides certain post-retirement health care and life insurance benefits to eligible contract employees. Premiums under this plan are expensed as incurred and amounted to $20 million, $26 million and $30 million in 2020, 2019 and 2018, respectively. The Company maintains savings plans for virtually all full-time salaried employees and certain employees covered by collective bargaining agreements. Expense associated with these plans was $39 million, $41 million and $41 million for 2020, 2019 and 2018, respectively, and is included in labor and fringe expense on the consolidated income statement.

Debt and Credit Agreements

Debt and Credit Agreements	12 Months Ended
Debt and Credit Agreements	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt and Credit Agreements	Debt and Credit Agreements Debt at December 2020 and December 2019 is shown in the table below. For information regarding the fair value of debt, see Note 13, Fair Value Measurements. Maturity at Average December December (Dollars in Millions) 2020 2020 2020 2019 Notes 2021-2068 4.0% $ 16,542 $ 16,056 Equipment Obligations (a) 2021-2023 6.3% 160 178 Finance Leases 2020-2026 14.5% 3 4 Subtotal Long-term Debt (including current portion) $ 16,705 $ 16,238 Less Debt Due within One Year (401) (245) Long-term Debt (excluding current portion) $ 16,304 $ 15,993 (a) Equipment obligations are secured by an interest in certain railroad equipment. Debt Issuance & Early Redemption of Long-term Debt CSX issued the following notes, which are included in the consolidated balance sheets under long-term debt and may be redeemed by the Company at any time, subject to payment of certain make-whole premiums: • On December 1, 2020, issued $500 million of 2.50% notes due 2051. On December 30, 2020, the proceeds of the offering were used to fully redeem CSX’s outstanding $500 million of 3.70% notes that otherwise would have matured on November 1, 2023. • On March 30, 2020, issued $500 million of 3.8% notes due 2050. • On September 12, 2019, issued $400 million of 2.40% notes due 2030 and $600 million of 3.35% notes due 2049. On October 15, 2019, a portion of the net proceeds was used to fully redeem CSX’s outstanding $500 million of 3.70% notes that otherwise would have matured on October 30, 2020. • On February 28, 2019, issued $600 million of 4.25% notes due 2029, which was a reopening of existing notes originally issued in November 2018, and $400 million of 4.50% notes due 2049. The net proceeds from debt issuances will be used for general corporate purposes, which may include debt repayments, repurchases of CSX's common stock, capital investment, working capital requirements, improvements in productivity and other cost reductions. For more information regarding a non-cash debt transaction with a related party, see Note 15, Investment in Affiliates and Related-Party Transactions. NOTE 10. Debt and Credit Agreements, continued Long-term Debt Maturities (Net of Discounts, Premiums and Issuance Costs) (Dollars in Millions) Maturities at Fiscal Years Ending December 2020 2021 $ 401 2022 162 2023 139 2024 551 2025 601 Thereafter 14,851 Total Long-term Debt Maturities, including current portion $ 16,705 Interest Rate Derivatives On both April 29, 2020, and July 9, 2020, the Company executed a forward starting interest rate swap with a notional value of $250 million for an aggregate notional value of $500 million. These swaps were effected to hedge the benchmark interest rate associated with future interest payments related to the anticipated refinancing of $850 million of 3.25% notes due in 2027. In accordance with the Derivatives and Hedging Topic in the ASC, the Company has designated these swaps as cash flow hedges. As of December 31, 2020, the asset value of the forward starting interest rate swaps was $80 million and was recorded in other long-term assets on the consolidated balance sheet. Unrealized gains or losses associated with changes in the fair value of the hedge are recorded net of tax in accumulated other comprehensive income (“AOCI”) on the consolidated balance sheet. Unless settled early, the swaps will expire in 2027 and the unrealized gain or loss in AOCI will be recognized in earnings as an adjustment to interest expense over the same period during which the hedged transaction affects earnings. Unrealized gains, recorded net of tax in other comprehensive income, related to the hedges were $62 million for the year ended December 31, 2020. Credit Facilities CSX has a $1.2 billion unsecured, revolving credit facility backed by a diverse syndicate of banks. This facility allows same-day borrowings at floating interest rates, based on LIBOR or an agreed-upon replacement, plus a spread that depends upon CSX's senior unsecured debt ratings. LIBOR is the London Interbank Offered Rate, which is a daily reference rate based on the interest rates at which banks offer to lend unsecured funds. This facility expires in March 2024, and as of December 31, 2020, the Company had no outstanding balances under this facility. Commitment fees and interest rates payable under the facility were similar to fees and rates available to comparably rated investment-grade borrowers. As of December 31, 2020, CSX was in compliance with all covenant requirements under the facility. Commercial Paper

Revenues

Revenues	12 Months Ended
Revenues	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Revenues	Revenues The Company’s revenues are primarily derived from the transportation of freight as performance obligations that arise from its contracts with customers are satisfied. The following table presents the Company’s revenues disaggregated by market as this best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Fiscal Years (Dollars in millions) 2020 2019 2018 Chemicals (a) $ 2,309 $ 2,349 $ 2,344 Agricultural and Food Products 1,386 1,410 1,306 Automotive 920 1,236 1,267 Forest Products (a) 824 862 834 Metals and Equipment (a) 675 742 771 Minerals (a) 538 559 527 Fertilizers 424 431 442 Total Merchandise 7,076 7,589 7,491 Intermodal 1,702 1,760 1,931 Coal 1,397 2,070 2,246 Other 408 518 582 Total $ 10,583 $ 11,937 $ 12,250 (a) In first quarter 2020, changes were made in the categorization of certain lines of business, impacting Chemicals, Forest Products, Metals and Equipment, and Minerals. The impacts were not material and prior periods have been reclassified to conform to the current presentation. Revenue Recognition The Company generates revenue from freight billings under contracts with customers generally on a rate per carload, container or ton-basis based on length of haul and commodities carried. The Company’s performance obligation arises when it receives a bill of lading (“BOL”) to transport a customer's commodities at a negotiated price contained in a transportation services agreement or a publicly disclosed tariff rate. Once a BOL is received, a contract is formed whereby the parties are committed to perform, collectability of consideration is probable and the rights of the parties, shipping terms and conditions, and payment terms are identified. A customer may submit several BOLs for transportation services at various times throughout a service agreement term, but each shipment represents a distinct service that is a separately identified performance obligation. NOTE 11. Revenues, continued The average transit time to complete a shipment is between 2 to 7 days depending on market. Payments for transportation services are normally billed once a BOL is received and are generally due within 15 days after the invoice date. The Company recognizes revenue over transit time of freight as it moves from origin to destination. Revenue for services started but not completed at the reporting date is allocated based on the relative transit time in each reporting period, with the portion allocated for services subsequent to the reporting date considered remaining performance obligations. The certain key estimates included in the recognition and measurement of revenue and related accounts receivable are as follows: • Revenue associated with shipments in transit is recognized ratably over transit time and is based on average cycle times to move commodities and products from their origin to their final destination or interchange; • Adjustments to revenue for billing corrections and billing discounts; • Adjustments to revenue for overcharge claims filed by customers, which are based on historical payments to customers for rate overcharges as a percentage of total billing; and • Incentive-based refunds to customers, which are primarily volume-related, are recorded as a reduction to revenue on the basis of the projected liability (this estimate is based on historical activity, current volume levels and forecasted future volume). Revenue related to interline transportation services that involve the services of another party, such as another railroad, is reported on a net basis. The portion of the gross amount billed to customers that is remitted by the Company to another party is not reflected as revenue. Other revenue is comprised of revenue from regional subsidiary railroads and incidental charges , including demurrage and switching. It is recorded upon completion of the service and accounts for an immaterial percentage of the Company’s total revenue. Revenue from regional subsidiary railroads includes shipments by railroads that the Company does not directly operate. Demurrage represents charges assessed when freight cars are held by a customer beyond a specified period of time. Switching represents charges assessed when a railroad switches cars for a customer or another railroad. During 2020, 2019 and 2018, revenue recognized from performance obligations related to prior periods (for example, due to changes in transaction price) was not material. Remaining Performance Obligations Remaining performance obligations represent the transaction price allocated to future reporting periods for freight services started but not completed at the reporting date . This includes the unearned portion of billed and unbilled amounts for cancellable freight shipments in transit. The Company expects to recognize the unearned portion of revenue for freight services in transit within one week of the reporting date. As of December 31, 2020, remaining performance obligations were not material. NOTE 11. Revenues, continued Contract Balances and Accounts Receivable The timing of revenue recognition, billings and cash collections results in accounts receivable and customer advances and deposits (contract liabilities) on the consolidated balance sheets. Contract assets, contract liabilities and deferred contract costs recorded on the consolidated balance sheet as of December 31, 2020 were not material. The Company’s accounts receivable - net consists of freight and non-freight receivables, reduced by an allowance for credit losses. (Dollars in millions) December 31, December 31, Freight Receivables $ 716 $ 790 Freight Allowance for Credit Losses (16) (21) Freight Receivables, net 700 769 Non-Freight Receivables 224 226 Non-Freight Allowance for Credit Losses (12) (9) Non-Freight Receivables, net 212 217 Total Accounts Receivable, net $ 912 $ 986 Freight receivables include amounts earned, billed and unbilled , and currently due from customers for transportation-related services. Non-freight receivables include amounts billed and unbilled and currently due related to government reimbursement receivables and other non-revenue receivables. The Company maintains an allowance for credit losses to provide for the estimated amount of receivables that will not be collected. The allowance is based upon an assessment of risk characteristics, historical payment experience, and the age of outstanding receivables adjusted for forward-looking economic conditions as necessary. Credit losses recognized on the Company’s accounts receivable were not material in 2020 and 2019.

Income Taxes

Income Taxes	12 Months Ended
Income Taxes	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Earnings before income taxes of $3.6 billion, $4.3 billion and $4.3 billion for fiscal years 2020, 2019 and 2018, respectively, represent earnings from domestic operations. The breakdown of income tax expense between current and deferred is as follows: Fiscal Years (Dollars in Millions) 2020 2019 2018 Current: Federal $ 559 $ 608 $ 572 State 123 104 144 Subtotal Current 682 712 716 Deferred: Federal 149 235 275 State 31 38 4 Subtotal Deferred 180 273 279 Total Income Tax Expense $ 862 $ 985 $ 995 The Company recorded a 2020 income tax benefit of $30 million primarily as a result of the additional tax benefit associated with vesting of share-based awards and the resolution of certain tax matters. In 2019, the Company recorded an income tax benefit of $77 million primarily as a result of the additional tax benefit associated with vesting of share-based awards, the settlement of certain state tax matters, federal and state legislative changes, and a change in the valuation of deferred taxes as a result of filing the 2018 tax returns. The Company recorded a 2018 income tax benefit of $62 million primarily as a result of the additional tax benefit associated with vesting of share-based awards, state legislative changes, the settlement of certain state tax matters and a change in the valuation of deferred taxes as a result of filing the 2017 tax returns. Income tax expense reconciled to the tax computed at statutory rates is presented in the following table. Fiscal Years (Dollars In Millions) 2020 2019 2018 Federal Income Taxes $ 762 21.0 % $ 906 21.0 % $ 904 21.0 % State Income Taxes 117 3.2 % 108 2.5 % 112 2.6 % Other (17) (0.4) % (29) (0.7) % (21) (0.5) % Income Tax Expense/ Rate $ 862 23.8 % $ 985 22.8 % $ 995 23.1 % NOTE 12. Income Taxes, continued The primary factors in the change in year-end net deferred income tax liability balances include the annual provision for deferred income tax expense and accumulated other comprehensive income/loss. The significant components of deferred income tax assets and liabilities include: 2020 2019 (Dollars in Millions) Assets Liabilities Assets Liabilities Pension Plans $ 62 $ — $ 71 $ — Other Employee Benefit Plans 96 — 127 — Accelerated Depreciation — 7,195 — 7,020 Other 320 451 426 565 Total $ 478 $ 7,646 $ 624 $ 7,585 Net Deferred Income Tax Liabilities $ 7,168 $ 6,961 The Company files a consolidated federal income tax return, which includes its principal domestic subsidiaries. CSX and its subsidiaries are subject to U.S. federal income tax as well as income tax of multiple state jurisdictions. CSX participated in a contemporaneous IRS audit of tax years 2020 and 2019. Federal examinations of original federal income tax returns for all years through 2018 are resolved. As of December 2020, 2019 and 2018, the Company had approximately $16 million, $13 million and $12 million, respectively, of total unrecognized tax benefits as a result of uncertain tax positions. These tax benefits that were $13 million, $10 million and $9 million net of tax in 2020, 2019 and 2018, respectively, could favorably impact the effective income tax rate in each year. The Company does not expect that unrecognized tax benefits as of December 2020 for various state and federal income tax matters will significantly change over the next 12 months. The final outcome of these uncertain tax positions is not yet determinable. There were no material changes to the total gross unrecognized tax benefits and prior year audit resolutions of the Company during the fiscal year ended December 2020.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements The Financial Instruments Topic in the ASC requires disclosures about fair value of financial instruments in annual reports as well as in quarterly reports. For CSX, this statement applies to certain investments, pension plan assets, long-term debt and interest rate derivatives. Also, the Fair Value Measurements and Disclosures Topic in the ASC clarifies the definition of fair value for financial reporting, establishes a framework for measuring fair value and requires additional disclosures about the use of fair value measurements. Various inputs are considered when determining the value of the Company's investments, pension plan assets, long-term debt and interest rate derivatives. The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in these securities. These inputs are summarized in the three broad levels listed below: • Level 1 – observable market inputs that are unadjusted quoted prices for identical assets or liabilities in active markets; • Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, credit risk, etc.); and • Level 3 – significant unobservable inputs (including the Company’s own assumptions about the assumptions market participants would use in determining the fair value of investments). The valuation methods described below may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. Investments The Company's investment assets, valued with assistance from a third-party trustee, consist of certificates of deposits, commercial paper, corporate bonds and government securities and are carried at fair value on the consolidated balance sheet per the Fair Value Measurements and Disclosures Topic in the ASC. There are several valuation methodologies used for those assets as described below: • Commercial Paper and Certificates of Deposit (Level 2): Valued at amortized cost, which approximates fair value; and • Corporate Bonds and Government Securities (Level 2): Valued using broker quotes that utilize observable market inputs. NOTE 13. Fair Value Measurements, continued The Company's investment assets are carried at fair value on the consolidated balance sheets as summarized in the following table. All of the inputs used to determine the fair value of the Company's investments are Level 2 inputs. Fiscal Years 2020 2019 (Dollars in Millions) Level 2 Level 2 Corporate Bonds $ 68 $ 59 Government Securities 33 36 Commercial Paper and Certificates of Deposit — 989 Total investments at fair value $ 101 $ 1,084 Total investments at amortized cost $ 89 $ 1,076 These investments have the following maturities and are represented on the consolidated balance sheet within short-term investments for investments with maturities of less than one year, and other long-term assets for investments with maturities of one year and greater. (Dollars in Millions) December 2020 December 2019 Less than 1 year $ 2 $ 996 1 - 5 years 22 10 5 - 10 years 23 25 Greater than 10 years 54 53 Total investments at fair value $ 101 $ 1,084 Long-term Debt Long-term debt, which includes finance leases, is reported at carrying amount on the consolidated balance sheets and is the Company's only financial instrument with fair values significantly different from their carrying amounts. The majority of the Company's long-term debt is valued with assistance from a third party that utilizes closing transactions, market quotes or market values of comparable debt. For those instruments not valued by the third party, the fair value has been estimated by applying market rates of similar instruments to the scheduled contractual debt payments and maturities. These market rates are provided by the same third party. All of the inputs used to determine the fair value of the Company's long-term debt are Level 2 inputs. The fair value of outstanding debt fluctuates with changes in a number of factors. Such factors include, but are not limited to, interest rates, market conditions, credit ratings, values of similar financial instruments, size of the transaction, cash flow projections and comparable trades. Fair value will exceed carrying value when the current market interest rate is lower than the interest rate at which the debt was originally issued. The fair value of a company's debt is a measure of its current value under present market conditions. It does not impact the financial statements under current accounting rules. NOTE 13. Fair Value Measurements, continued The fair value and carrying value of the Company's long-term debt is as follows: (Dollars in Millions) December 2020 December 2019 Long-term Debt (Including Current Maturities): Fair Value $ 21,076 $ 18,503 Carrying Value 16,705 16,238 Interest Rate Derivatives The Company’s forward starting interest rate swaps are carried at fair value and valued with assistance from a third party based upon pricing models using inputs observed from actively quoted markets. All of the inputs used to determine the fair value of the swaps are Level 2 inputs. The fair value of the Company’s forward starting interest rate swaps asset was $80 million at December 31, 2020. See Note 10, Debt and Credit Agreements for further information. Pension Plan Assets Pension plan assets are reported at fair value, net of pension liabilities, on the consolidated balance sheet. The Investment Committee targets an allocation of pension assets to be generally 60% growth-oriented and 40% immunizing. See Note 9, Employee Benefit Plans for further information. There are several valuation methodologies used for those assets as described below. Investments in the Fair Value Hierarchy • Common stock (Level 1): Valued at the closing price reported on the active market on which the individual securities are traded on the last day of the year and classified in Level 1 of the fair value hierarchy. • Mutual funds (Level 1 ): Valued at the net asset value of shares held at year end based on quoted market prices determined in an active market. These assets are classified in Level 1 of the fair value hierarchy. • Cash and cash equivalents (Level 1) : Includes cash and short term investments with an original maturity of three months or less. The carrying value of cash and cash equivalents at year end approximates fair value. These assets are classified in Level 1 of the fair value hierarchy. • Corporate bonds, government securities, asset-backed securities and derivatives (Level 2) : Valued using price evaluations reflecting the bid and/or ask sides of the market for a similar investment at year end. Asset-backed securities include commercial mortgage-backed securities and collateralized mortgage obligations. These assets are classified in Level 2 of the fair value hierarchy. Investments Measured at Net Asset Value • Partnerships: Net asset value of private equity is based on the fair market values associated with the underlying investments at year end. These funds have redemption restrictions that require advanced notice of 15 business days. • Commingled and common collective trust funds: This class consists of private funds that invest in corporate equity and debt securities, government securities and various short-term debt instruments and are measured at net asset value to estimate the fair value of the investments. The net asset value of the investments is determined by reference to the fair value of the underlying securities, which are valued primarily through the use of directly or indirectly observable inputs. These funds have redemption restrictions that require advanced notice of up to 15 business days. NOTE 13. Fair Value Measurements, continued The pension plan assets at fair value by level, within the fair value hierarchy, as of calendar plan years 2020 and 2019 are shown in the table below. For additional information related to pension assets, see Note 9, Employee Benefit Plans. Fiscal Years 2020 2019 (Dollars in Millions) Level 1 Level 2 Total Level 1 Level 2 Total Common Stock $ 337 $ — $ 337 $ 823 $ — $ 823 Mutual funds 21 — 21 78 — 78 Cash and cash equivalents 387 — 387 229 — 229 Corporate bonds — 1,026 1,026 — 588 588 Government securities — 164 164 — 217 217 Asset-backed securities, derivatives and other — 85 85 — 17 17 Total investments in the fair value hierarchy $ 745 $ 1,275 $ 2,020 $ 1,130 $ 822 $ 1,952 Investments measured at net asset value (a) n/a n/a $ 980 n/a n/a $ 873 Investments at fair value $ 745 $ 1,275 $ 3,000 $ 1,130 $ 822 $ 2,825

Other Income - Net

Other Income - Net	12 Months Ended
Other Income - Net	Dec. 31, 2020
Other Income and Expenses [Abstract]
Other Income - Net	Other Income - Net The Company derives income from items that are not considered operating activities. Income from these items is reported net of related expense. All components of net periodic pension and post-retirement benefit costs, excluding service cost, are included in other income - net on the consolidated income statement. Miscellaneous income (expense) may fluctuate due to timing and includes investment gains, losses and interest income as well as other non-operating activities. Interest income decreased from 2019 to 2020 primarily as a result of lower interest rates, partially offset by higher average investment balances. Interest income increased from 2018 to 2019 primarily as a result of higher average cash and short-term investment balances. Debt repurchase expense increased from 2019 to 2020 primarily as a result of long-term debt being redeemed earlier relative to maturity date. Other income – net consisted of the following: Fiscal Years (Dollars in Millions) 2020 2019 2018 Net Periodic Pension and Post-retirement Benefit Credit (a) $ 42 $ 43 $ 38 Interest Income 17 48 32 Debt Repurchase Expense (48) (10) — Miscellaneous Income 8 7 4 Total Other Income - Net $ 19 $ 88 $ 74

Investment in Affiliates and Re

Investment in Affiliates and Related-Party Transactions	12 Months Ended
Investment in Affiliates and Related-Party Transactions	Dec. 31, 2020
Related Party Transactions [Abstract]
Investment in Affiliates and Related-Party Transactions	Investment in Affiliates and Related-Party Transactions CSX's investments in affiliates are included on the consolidated balance sheet as investments in affiliates and other companies. December December (Dollars in Millions) 2020 2019 Equity-method investments: Conrail $ 1,025 $ 982 TTX 796 743 Other 164 154 Total $ 1,985 $ 1,879 Conrail Through a limited liability company, CSX and Norfolk Southern Corporation (“NS”) jointly own Conrail. CSX has a 42% economic interest and 50% voting interest in the jointly-owned entity, and NS has the remainder of the economic and voting interests. Pursuant to the Investments-Equity Method and Joint Venture Topic in the ASC, CSX applies the equity method of accounting to its investment in Conrail. Conrail owns rail infrastructure and operates for the joint benefit of CSX and NS. This is known as the shared asset area. Conrail charges fees for right-of-way usage, equipment rentals and transportation, switching and terminal service charges in the shared asset area. These expenses are included in materials, supplies and other on the consolidated income statements. Future payments due to Conrail under the shared asset area agreements are shown in the table below. (Dollars in Millions) Conrail Shared Years Asset Agreement 2021 $ 30 2022 30 2023 30 2024 22 2025 — Thereafter — Total $ 112 Also, included in equity earnings of affiliates are CSX’s 42 percent share of Conrail’s income and its amortization of the fair value write-up arising from the acquisition of Conrail and certain other adjustments. The amortization primarily represents the additional after-tax depreciation expense related to the write-up of Conrail’s fixed assets when the original purchase price, from the 1997 acquisition of Conrail, was allocated based on fair value. This write-up of fixed assets resulted in a difference between CSX's investment in Conrail and its share of Conrail's underlying net equity, which is $335 million as of December 2020. NOTE 15. Investment in Affiliates and Related-Party Transactions, continued The following table discloses amounts related to Conrail. All amounts in the table below are included in materials, supplies and other expenses on the Company’s consolidated income statements. Fiscal Years (Dollars in Millions) 2020 2019 2018 Rents, fees and services $ 126 $ 119 $ 117 Purchase price amortization and other 4 4 4 Equity earnings of Conrail (49) (42) (43) Total Conrail Expense $ 81 $ 81 $ 78 As required by the Related Party Disclosures Topic in the ASC, the Company has identified amounts below owed to Conrail, or its subsidiaries, representing liabilities under the operating, equipment and shared area agreements with Conrail. In 2014, the Company executed two promissory notes with a subsidiary of Conrail which were included in long-term debt on the consolidated balance sheets. Interest expense from these promissory notes was $6 million in each 2020, 2019 and 2018. December December (Dollars in Millions) 2020 2019 Balance Sheet Information: CSX accounts payable to Conrail $ 50 $ 213 Promissory notes payable to Conrail subsidiary 1.31% CSX Promissory Note due December 2050 73 — 1.31% CSXT Promissory Note due December 2050 368 — 2.89% CSX Promissory Note due October 2044 — 73 2.89% CSXT Promissory Note due October 2044 — 151 In December 2020, the Company completed a non-cash conversion of its existing payable balance of approximately $217 million and $224 million, 2.89% notes due 2044 into new notes. The new notes for operation of the shared asset area are $441 million, 1.31% notes due 2050. TTX Company TTX Company ("TTX") is a privately-held corporation engaged in the business of providing its owner-railroads with standardized fleets of intermodal, automotive and general use railcars at time and mileage rates. CSX owns about 20 percent of TTX's common stock, and the remaining is owned by the other leading North American railroads and their affiliates. Pursuant to the Investments-Equity Method topic in the ASC, CSX applies the equity method of accounting to its investment in TTX. NOTE 15. Investment in Affiliates and Related-Party Transactions, continued As required by the Related Party Disclosures Topic in the ASC, the following table discloses amounts related to TTX. Car hire rents and equity earnings are included in equipment and other rents expense on the Company’s consolidated income statement. Fiscal Years (Dollars in Millions) 2020 2019 2018 Income statement information: Car hire rents $ 219 $ 223 $ 223 Equity earnings of TTX (51) (56) (60) Total TTX expense $ 168 $ 167 $ 163 Also included below is balance sheet information related to CSX's payable to TTX, which represents car rental liabilities. December December Balance sheet information: 2020 2019 CSX payable to TTX $ 40 $ 34 Other Related Party Transactions On October 17, 2019, the Company repurchased 4.7 million shares for $319 million from MR Argent Advisor LLC, a CSX shareholder on behalf of certain limited partners of its affiliated funds. See additional discussion in Note 2, Earnings Per Share.

Other Comprehensive Income _ (L

Other Comprehensive Income / (Loss)	12 Months Ended
Other Comprehensive Income / (Loss)	Dec. 31, 2020
Equity [Abstract]
Other Comprehensive Income / (Loss)	Other Comprehensive Income / (Loss) CSX reports comprehensive earnings or loss in accordance with the Comprehensive Income Topic in the ASC in the consolidated comprehensive income statement. Total comprehensive earnings are defined as all changes in shareholders' equity during a period, other than those resulting from investments by and distributions to shareholders (e.g., issuance of equity securities and dividends). Generally, for CSX, total comprehensive earnings equal net earnings plus or minus adjustments for pension and other post-retirement liabilities as well as other adjustments. Total comprehensive earnings represent the activity for a period net of tax and were $2.8 billion, $3.3 billion and $3.1 billion for 2020, 2019 and 2018, respectively. While total comprehensive earnings is the activity in a period and is largely driven by net earnings in that period, accumulated other comprehensive income or loss (“AOCI”) represents the cumulative balance of other comprehensive income, net of tax, as of the balance sheet date. For CSX, AOCI is primarily the cumulative balance related to pension and other post-retirement benefit adjustments, interest rate derivatives and CSX's share of AOCI of equity method investees. NOTE 16. Other Comprehensive Income / (Loss), continued Changes in the AOCI balance by component are shown in the following table. Amounts reclassified in pension and other post-employment benefits to net earnings relate to the amortization of actuarial losses and are included in other income-net on the consolidated income statements. See Note 9. Employee Benefit Plans for further information. Interest rate derivatives consist of forward starting interest rate swaps classified as cash flow hedges. See Note 10, Debt and Credit Agreements for further information. Other primarily represents CSX's share of AOCI of equity method investees. Amounts reclassified in other to net earnings are included in materials, supplies, and other or equipment and other rents on the consolidated income statements. Pension and Other Post-Employment Benefits Interest Rate Derivatives Other Accumulated Other Comprehensive Income (Loss) (Dollars in millions) Balance December 31, 2017 - Net of Tax $ (440) $ — $ (46) $ (486) Other Comprehensive Income (Loss) Reclassification of Stranded Tax Effects (a) (108) — 1 (107) Loss Before Reclassifications (111) — (8) (119) Amounts Reclassified to Net Earnings 38 — (6) 32 Tax Benefit 17 — 2 19 Total Other Comprehensive Loss (164) — (11) (175) Balance December 31, 2018 - Net of Tax (604) — (57) (661) Other Comprehensive Income (Loss) Loss Before Reclassifications (43) — (5) (48) Amounts Reclassified to Net Earnings 23 — 8 31 Tax Benefit (Expense) 5 — (2) 3 Total Other Comprehensive (Loss) Income (15) — 1 (14) Balance December 31, 2019 - Net of Tax (619) — (56) (675) Other Comprehensive Income (Loss) (Loss) Income Before Reclassifications (17) 80 (10) 53 Amounts Reclassified to Net Earnings 47 — 5 52 Tax Expense (9) (18) (1) (28) Total Other Comprehensive Income (Loss) 21 62 (6) 77 Balance December 31, 2020 - Net of Tax $ (598) $ 62 $ (62) $ (598)

Nature of Operations and Sign_2

Nature of Operations and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	In the opinion of management, the accompanying consolidated financial statements contain all normal, recurring adjustments necessary to fairly present the financial position of CSX and its subsidiaries at December 31, 2020 and December 31, 2019, and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2020, 2019 and 2018. Where applicable, prior year information has been reclassified to conform to current presentation. In addition, management has evaluated and disclosed all material events occurring subsequent to the date of the financial statements up to the date this annual report is filed on Form 10-K.
Fiscal Year	The Company's fiscal periods are based upon the calendar year. Except as otherwise specified, references to full years indicate CSX’s fiscal years ended on December 31, 2020, December 31, 2019 and December 31, 2018.
Principles of Consolidation	The consolidated financial statements include results of operations of CSX and subsidiaries over which CSX has majority ownership or financial control. All significant intercompany accounts and transactions have been eliminated. Most investments in companies that were not majority-owned were carried at cost (if less than 20% owned and the Company has no significant influence) or were accounted for under the equity method (if the Company has significant influence but does not have control). These investments are reported within Investment in Affiliates and Other Companies on the consolidated balance sheets.
Cash and Cash Equivalents	On a daily basis, cash in excess of current operating requirements is invested in various highly liquid investments having a typical maturity date of three months or less at the date of acquisition. These investments are carried at cost, which approximates market value, and are classified as cash equivalents.
Investments	Investments in instruments with original maturities greater than three months that will mature in less than one year are classified as short-term investments. Investments with original maturities of one year or greater are initially classified within other long-term assets, and the classification is re-evaluated at each balance sheet date.
Materials and Supplies	Materials and supplies in the consolidated balance sheets are carried at average cost and consist primarily of parts used in the repair and maintenance of track structure, equipment, and CSXT’s freight car and locomotive fleets, as well as fuel.
New Accounting Pronouncements	In June 2016, the FASB issued ASU Measurement of Credit Losses on Financial Instruments, which replaces current methods for evaluating impairment of financial instruments not measured at fair value, including trade accounts receivable and certain debt securities, with a current expected credit loss model. CSX was required to adopt this new standard update by January 1, 2020. Adoption did not have a material effect on the Company's results of operations.In August 2018, the FASB issued ASU Changes to the Disclosure Requirements for Defined Benefit Plans as part of its disclosure effectiveness initiative, which modifies the disclosure requirements for employer-sponsored defined benefit pension and other postretirement plans. CSX was required to adopt this new standard update by January 1, 2020. Adoption did not have a material impact on the Company's disclosures.
Use of Estimates	The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires that management make estimates in reporting the amounts of certain assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of certain revenues and expenses during the reporting period. Actual results may differ from those estimates. Critical accounting estimates using management judgment are made for the following areas: • personal injury, environmental and legal reserves (see Note 5, Casualty, Environmental and Other Reserves ); • pension and post-retirement medical plan accounting (see Note 9, Employee Benefit Plans ); and • depreciation policies for assets under the group-life method (see Note 6, Properties ).
Earnings Per Share	Basic earnings per share is based on the weighted-average number of shares of common stock outstanding. Earnings per share, assuming dilution, is based on the weighted-average number of shares of common stock outstanding and common stock equivalents adjusted for the effects of common stock that may be issued as a result of potentially dilutive instruments. CSX's potentially dilutive instruments are made up of equity awards including performance units and employee stock options. When calculating diluted earnings per share, the potential shares that would be outstanding if all outstanding stock options were exercised are included. This number is different from outstanding stock options, which is included in Note 4, Stock Plans and Share-Based Compensation, because it is offset by shares CSX could repurchase using the proceeds from these hypothetical exercises to obtain the common stock equivalent.
Stock Plans and Share-Based Compensation	Under CSX's share-based compensation plans, awards consist of performance units, stock options, restricted stock units and restricted stock awards for management and stock grants for directors. Awards granted under the various programs are determined and approved by the Compensation and Talent Management Committee of the Board of Directors. Awards to the Chief Executive Officer are approved by the full Board and awards to senior executives are approved by the Compensation and Talent Management Committee. In certain circumstances, the Chief Executive Officer or delegate approves awards to management employees other than senior executives. The Board of Directors approves awards granted to CSX's non-management directors upon recommendation of the Governance and Sustainability Committee. Share-based compensation expense for awards under share-based compensation plans and purchases made as part of the employee stock purchase plan is measured using the fair value of the award on the grant date and is recognized on a straight-line basis over the service period of the respective award or upon grant date to certain retirement-eligible employees whose agreements allow for continued vesting upon retirement. Forfeitures are recognized as they occur.
Casualty Reserves	The Company's self-insured retention amount for these claims is $75 million per occurrence. Currently, no individual claim is expected to exceed the self-insured retention amount. Most of the Company's casualty claims relate to CSXT. In accordance with the Contingencies Topic in the ASC, to the extent the value of an individual claim exceeds the self-insured retention amount, the Company would present the liability on a gross basis with a corresponding receivable for insurance recoveries. These reserves fluctuate based upon the timing of payments as well as changes in estimate. Actual results may vary from estimates due to the number, type and severity of the injury, costs of medical treatments and uncertainties in litigation. Defense and processing costs, which historically have been insignificant and are anticipated to be insignificant in the future, are not included in the recorded liabilities. Changes in casualty reserves are included in materials, supplies and other on the consolidated income statements. NOTE 5. Casualty, Environmental and Other Reserves, continued Personal Injury Personal injury reserves represent liabilities for employee work-related and third-party injuries. Work-related injuries for CSXT employees are primarily subject to the Federal Employers' Liability Act ("FELA"). CSXT retains an independent actuary to assist management in assessing the value of personal injury claims. An analysis is performed by the actuary quarterly and is reviewed by management. The methodology used by the actuary includes a development factor to reflect growth or reduction in the value of these personal injury claims based largely on CSXT's historical claims and settlement experience. These analyses did not result in a material adjustment to the personal injury reserve in 2020, 2019 or 2018. Occupational Occupational reserves represent liabilities arising from allegations of exposure to certain materials in the workplace (such as solvents, soaps, chemicals and diesel fumes), past exposure to asbestos or allegations of chronic physical injuries resulting from work conditions (such as repetitive stress injuries). Beginning in second quarter 2020, the Company retains an independent actuary to analyze the Company’s historical claim filings, settlement amounts, and dismissal rates to assist in determining future anticipated claim filing rates and average settlement values. This analysis is performed by the actuary and reviewed by management quarterly. Previously, the quarterly analysis was performed by management. There were no material adjustments to the occupational reserve in 2020, 2019 or 2018.
Environmental Reserves	The Company is a party to various proceedings related to environmental issues, including administrative and judicial proceedings involving private parties and regulatory agencies. The Company has been identified as a potentially responsible party at approximately 220 environmentally impaired sites. Many of these are, or may be, subject to remedial action under the federal Comprehensive Environmental Response, Compensation and Liability Act of 1980 ("CERCLA"), also known as the Superfund Law, or similar state statutes. Most of these proceedings arose from environmental conditions on properties used for ongoing or discontinued railroad operations. A number of these proceedings, however, are based on allegations that the Company, or its predecessors, sent hazardous substances to facilities owned or operated by others for treatment, recycling or disposal. In addition, some of the Company’s land holdings were leased to others for commercial or industrial uses that may have resulted in releases of hazardous substances or other regulated materials onto the property and could give rise to proceedings against the Company.In any such proceedings, the Company is subject to environmental clean-up and enforcement actions under the Superfund Law, as well as similar state laws that may impose joint and several liability for clean-up and enforcement costs on current and former owners and operators of a site without regard to fault or the legality of the original conduct. These costs could be substantial. NOTE 5. Casualty, Environmental and Other Reserves, continued In accordance with the Asset Retirement and Environmental Obligations Topic in the ASC, the Company reviews its role with respect to each site identified at least quarterly, giving consideration to a number of factors such as: • type of clean-up required; • nature of the Company’s alleged connection to the location (e.g., generator of waste sent to the site or owner or operator of the site); • extent of the Company’s alleged connection (e.g., volume of waste sent to the location and other relevant factors); and • number, connection and financial viability of other named and unnamed potentially responsible parties at the location. Based on management's review process, amounts have been recorded to cover contingent anticipated future environmental remediation costs with respect to each site to the extent such costs are reasonably estimable and probable. The recorded liabilities for estimated future environmental costs are undiscounted. The liability includes future costs for remediation and restoration of sites as well as any significant ongoing monitoring costs, but excludes any anticipated insurance recoveries. Payments related to these liabilities are expected to be made over the next several years. Environmental remediation costs are included in materials, supplies and other on the consolidated income statements. Currently, the Company does not possess sufficient information to reasonably estimate the amounts of additional liabilities, if any, on some sites until completion of future environmental studies. In addition, conditions that are currently unknown could, at any given location, result in additional exposure, the amount and materiality of which cannot presently be reasonably estimated. Based upon information currently available, however, the Company believes its environmental reserves accurately reflect the estimated cost of remedial actions currently required.
Capital Expenditures	The Company’s capital investment includes purchased and self-constructed assets and property additions that substantially extend the service life or increase the utility of those assets. Indirect costs that can be specifically traced to capital projects are also capitalized. The Company is committed to maintaining and improving its existing infrastructure and expanding its network capacity for long-term growth. Rail operations are capital intensive and CSX accounts for these costs in accordance with GAAP and the Company’s capitalization policy. All properties are stated at historical cost less an allowance for accumulated depreciation. The Company’s largest category of capital investment is the replacement of track assets and the acquisition or construction of new assets that enable CSX to enhance its operations or provide new capacity offerings to its customers. These construction projects are primarily completed by CSXT employees. Costs for track asset replacement and capacity projects that are capitalized include: • labor costs, because many of the assets are self-constructed; • costs to purchase or construct new track or to prepare ground for the laying of track; • welding (rail, field and plant), which are processes used to connect segments of rail; • new ballast, which is gravel and crushed stone that holds track in line; • fuels and lubricants associated with tie, rail and surfacing work, which is the process of raising track to a designated elevation over an extended distance; • cross, switch and bridge ties, which are the braces that support the rails on a track; • gauging, which is the process of standardizing the distance between rails; • handling costs associated with installing rail, ties or ballast; • usage charge of machinery and equipment utilized in construction or installation; and • other track materials. Labor is a significant cost in self-constructed track replacement work. CSXT engineering employees directly charge their labor to the track replacement project (the capitalized depreciable property). In replacing track, these employees concurrently perform deconstruction and installation of track material. Because of this concurrent process, CSX must estimate the amount of labor that is related to deconstruction versus installation. As a component of the depreciation study for road and track assets, management performs an analysis of labor costs related to the self-constructed track replacement work, which includes direct observation of track replacement processes. Through this analysis, CSX determined that approximately 20% of labor costs associated with track replacement is related to the deconstruction of old track, for which certain elements are expensed, and 80% is associated with the installation of new track, which is capitalized. Capital investment related to locomotives and freight cars comprises the second largest category of the Company’s capital assets. This category includes purchases of locomotives and freight cars as well as certain equipment leases that are considered to be finance leases in accordance with the Leases Topic in the ASC. In addition, costs to modify or rebuild these assets are capitalized if the investment incurred extends the asset’s service life or improves utilization. Improvement projects must meet specified dollar thresholds to be capitalized and are reviewed by management to determine proper accounting treatment. Routine repairs, overhauls and other maintenance costs, for all asset categories, are expensed as incurred. Group-Life Assets Sales and Retirements Since the rail network is one contiguous, connected network it is impractical to maintain specific identification records for these assets. For track assets (e.g., rail, ties, and ballast), CSX utilizes a first-in, first-out approach to asset retirements. Equipment assets (e.g., locomotives and freight cars) are specifically identified at retirement. When an equipment asset is retired that has been depreciated using the group-life method, the cost is reduced from the cost base and recorded in accumulated depreciation. For sales or retirements of assets depreciated under the group-life method that occur in the ordinary course of business, the asset cost (net of salvage value or sales proceeds) is charged to accumulated depreciation and no gain or loss is immediately recognized. This practice is consistent with accounting treatment prescribed under the group-life method. As part of the depreciation study, an assessment of the recorded amount of accumulated depreciation is made to determine if it is deficient (or in excess) of the appropriate amount indicated by the study. Any such deficiency (or excess), including any deferred gains or losses, is amortized as a component of depreciation expense over the remaining service life of the asset group until the next required depreciation study. Since the overall assumption with the group-life method is that the assets within the group on average have the same service life and characteristics, it is therefore concluded that the deferred gains and losses offset over time. For sales or retirements of assets depreciated under the group-life method that do not occur in the ordinary course of business, a gain or loss may be recognized if the sale or retirement meets each of the following three criteria: (i) it is unusual, (ii) it is material in amount, and (iii) it varies significantly from the retirement profile identified through our depreciation studies. No material gains or losses were recognized on the sale of assets depreciated using the group-life method in 2020, 2019, or 2018 as no sales met the criteria described above. Land and Straight-line Assets Sales and Retirements
Depreciation Method	The depreciable assets of the Company are depreciated using either the group-life or straight-line method of accounting, which are both acceptable depreciation methods in accordance with GAAP. The Company depreciates its railroad assets, including main-line track, locomotives and freight cars, using the group-life method. Assets depreciated under the group-life method comprise 87% of total fixed assets of $45.5 billion on a gross basis as of December 2020. The remaining depreciable assets of the Company, including non-railroad assets and assets under finance leases, are depreciated using the straight-line method on a per asset basis. Land is not depreciated. The group-life method aggregates assets with similar lives and characteristics into groups and depreciates each of these groups as a whole. When using the group-life method, an underlying assumption is that each group of assets, as a whole, is used and depreciated to the end of its group’s recoverable life. The Company currently utilizes different depreciable asset categories to account for depreciation expense for the railroad assets that are depreciated under the group-life method. By utilizing various depreciable categories, the Company can more accurately account for the use of its assets. All assets of the Company are depreciated on a time or life basis. The group-life method of depreciation closely approximates the straight-line method of depreciation. Additionally, due to the nature of most of its assets (e.g. track is one contiguous, connected asset), the Company believes that this is the most accurate and effective way to properly depreciate its assets. Estimated Useful Life
Impairment Review	Properties and other long-lived assets are reviewed for impairment whenever events or business conditions indicate the carrying amount of such assets may not be fully recoverable. Initial assessments of recoverability are based on estimates of undiscounted future net cash flows associated with an asset or a group of assets in accordance with the Property, Plant, and Equipment Topic
Leases	At inception, the Company determines if an arrangement contains a lease and whether that lease meets the classification criteria of a finance or operating lease. Some of the Company’s lease arrangements contain lease components (e.g., minimum rent payments) and non-lease components (e.g., maintenance, labor charges, etc.). The Company generally accounts for each component separately based on the estimated standalone price of each component. For certain equipment leases, such as freight car, vehicles and work equipment, the Company accounts for the lease and non-lease components as a single lease component. Certain of the Company’s lease agreements include rental payments that are adjusted periodically for an index or rate. The leases are initially measured using the projected payments adjusted for the index or rate in effect at the commencement date. The Company’s lease agreements do not contain any material residual value guarantees or material restrictive covenants. Operating Leases Operating leases are included in right-of-use lease assets, other current liabilities and long-term lease liabilities on the consolidated balance sheets. These assets and liabilities are recognized at the commencement date based on the present value of remaining lease payments over the lease term using the Company’s secured incremental borrowing rates or implicit rates, when readily determinable. Short-term operating leases, which have an initial term of 12 months or less, are not recorded on the balance sheet. The Company has various lease agreements with other parties with terms up to 50 years. Non-cancelable, long-term leases may include provisions for maintenance, options to purchase and options to extend the terms. These options are included in the lease term when it is reasonably certain that the option will be exercised. Lease expense for operating leases, including leases with escalations over their terms, is recognized on a straight-line basis over the lease term. Variable lease expense is recognized in the period in which the obligation for those payments is incurred. Lease expense is included in equipment and other rents on the consolidated income statements and is reported net of lease income. Lease income was not material to the results of operations for 2020, 2019 or 2018.
Revenue Recognition	The Company’s revenues are primarily derived from the transportation of freight as performance obligations that arise from its contracts with customers are satisfied. The following table presents the Company’s revenues disaggregated by market as this best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors.The Company generates revenue from freight billings under contracts with customers generally on a rate per carload, container or ton-basis based on length of haul and commodities carried. The Company’s performance obligation arises when it receives a bill of lading (“BOL”) to transport a customer's commodities at a negotiated price contained in a transportation services agreement or a publicly disclosed tariff rate. Once a BOL is received, a contract is formed whereby the parties are committed to perform, collectability of consideration is probable and the rights of the parties, shipping terms and conditions, and payment terms are identified. A customer may submit several BOLs for transportation services at various times throughout a service agreement term, but each shipment represents a distinct service that is a separately identified performance obligation. NOTE 11. Revenues, continued The average transit time to complete a shipment is between 2 to 7 days depending on market. Payments for transportation services are normally billed once a BOL is received and are generally due within 15 days after the invoice date. The Company recognizes revenue over transit time of freight as it moves from origin to destination. Revenue for services started but not completed at the reporting date is allocated based on the relative transit time in each reporting period, with the portion allocated for services subsequent to the reporting date considered remaining performance obligations. The certain key estimates included in the recognition and measurement of revenue and related accounts receivable are as follows: • Revenue associated with shipments in transit is recognized ratably over transit time and is based on average cycle times to move commodities and products from their origin to their final destination or interchange; • Adjustments to revenue for billing corrections and billing discounts; • Adjustments to revenue for overcharge claims filed by customers, which are based on historical payments to customers for rate overcharges as a percentage of total billing; and • Incentive-based refunds to customers, which are primarily volume-related, are recorded as a reduction to revenue on the basis of the projected liability (this estimate is based on historical activity, current volume levels and forecasted future volume). Revenue related to interline transportation services that involve the services of another party, such as another railroad, is reported on a net basis. The portion of the gross amount billed to customers that is remitted by the Company to another party is not reflected as revenue. Other revenue is comprised of revenue from regional subsidiary railroads and incidental charges , including demurrage and switching. It is recorded upon completion of the service and accounts for an immaterial percentage of the Company’s total revenue. Revenue from regional subsidiary railroads includes shipments by railroads that the Company does not directly operate. Demurrage represents charges assessed when freight cars are held by a customer beyond a specified period of time. Switching represents charges assessed when a railroad switches cars for a customer or another railroad. During 2020, 2019 and 2018, revenue recognized from performance obligations related to prior periods (for example, due to changes in transaction price) was not material. Remaining Performance Obligations Remaining performance obligations represent the transaction price allocated to future reporting periods for freight services started but not completed at the reporting date . This includes the unearned portion of billed and unbilled amounts for cancellable freight shipments in transit. The Company expects to recognize the unearned portion of revenue for freight services in transit within one week of the reporting date. As of December 31, 2020, remaining performance obligations were not material. NOTE 11. Revenues, continued Contract Balances and Accounts Receivable
Allowance for Credit Losses	Freight receivables include amounts earned, billed and unbilled , and currently due from customers
Fair Value Measurements	The Financial Instruments Topic in the ASC requires disclosures about fair value of financial instruments in annual reports as well as in quarterly reports. For CSX, this statement applies to certain investments, pension plan assets, long-term debt and interest rate derivatives. Also, the Fair Value Measurements and Disclosures Topic in the ASC clarifies the definition of fair value for financial reporting, establishes a framework for measuring fair value and requires additional disclosures about the use of fair value measurements. Various inputs are considered when determining the value of the Company's investments, pension plan assets, long-term debt and interest rate derivatives. The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in these securities. These inputs are summarized in the three broad levels listed below: • Level 1 – observable market inputs that are unadjusted quoted prices for identical assets or liabilities in active markets; • Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, credit risk, etc.); and • Level 3 – significant unobservable inputs (including the Company’s own assumptions about the assumptions market participants would use in determining the fair value of investments). The valuation methods described below may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. Investments The Company's investment assets, valued with assistance from a third-party trustee, consist of certificates of deposits, commercial paper, corporate bonds and government securities and are carried at fair value on the consolidated balance sheet per the Fair Value Measurements and Disclosures Topic in the ASC. There are several valuation methodologies used for those assets as described below: • Commercial Paper and Certificates of Deposit (Level 2): Valued at amortized cost, which approximates fair value; and • Corporate Bonds and Government Securities (Level 2): Valued using broker quotes that utilize observable market inputs. Long-term Debt Long-term debt, which includes finance leases, is reported at carrying amount on the consolidated balance sheets and is the Company's only financial instrument with fair values significantly different from their carrying amounts. The majority of the Company's long-term debt is valued with assistance from a third party that utilizes closing transactions, market quotes or market values of comparable debt. For those instruments not valued by the third party, the fair value has been estimated by applying market rates of similar instruments to the scheduled contractual debt payments and maturities. These market rates are provided by the same third party. All of the inputs used to determine the fair value of the Company's long-term debt are Level 2 inputs. The fair value of outstanding debt fluctuates with changes in a number of factors. Such factors include, but are not limited to, interest rates, market conditions, credit ratings, values of similar financial instruments, size of the transaction, cash flow projections and comparable trades. Fair value will exceed carrying value when the current market interest rate is lower than the interest rate at which the debt was originally issued. The fair value of a company's debt is a measure of its current value under present market conditions. It does not impact the financial statements under current accounting rules. Interest Rate Derivatives The Company’s forward starting interest rate swaps are carried at fair value and valued with assistance from a third party based upon pricing models using inputs observed from actively quoted markets. All of the inputs used to determine the fair value of the swaps are Level 2 inputs. The fair value of the Company’s forward starting interest rate swaps asset was $80 million at December 31, 2020. See Note 10, Debt and Credit Agreements for further information. Pension Plan Assets Pension plan assets are reported at fair value, net of pension liabilities, on the consolidated balance sheet. The Investment Committee targets an allocation of pension assets to be generally 60% growth-oriented and 40% immunizing. See Note 9, Employee Benefit Plans for further information. There are several valuation methodologies used for those assets as described below. Investments in the Fair Value Hierarchy • Common stock (Level 1): Valued at the closing price reported on the active market on which the individual securities are traded on the last day of the year and classified in Level 1 of the fair value hierarchy. • Mutual funds (Level 1 ): Valued at the net asset value of shares held at year end based on quoted market prices determined in an active market. These assets are classified in Level 1 of the fair value hierarchy. • Cash and cash equivalents (Level 1) : Includes cash and short term investments with an original maturity of three months or less. The carrying value of cash and cash equivalents at year end approximates fair value. These assets are classified in Level 1 of the fair value hierarchy. • Corporate bonds, government securities, asset-backed securities and derivatives (Level 2) : Valued using price evaluations reflecting the bid and/or ask sides of the market for a similar investment at year end. Asset-backed securities include commercial mortgage-backed securities and collateralized mortgage obligations. These assets are classified in Level 2 of the fair value hierarchy. Investments Measured at Net Asset Value • Partnerships: Net asset value of private equity is based on the fair market values associated with the underlying investments at year end. These funds have redemption restrictions that require advanced notice of 15 business days. • Commingled and common collective trust funds:

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
Earnings Per Share (Tables)	Dec. 31, 2020
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings per Share	The following table sets forth the computation of basic earnings per share and earnings per share, assuming dilution: Fiscal Years 2020 2019 2018 Numerator (Dollars in Millions) : Net Earnings $ 2,765 $ 3,331 $ 3,309 Dividend Equivalents on Restricted Stock — — (1) Net Earnings, Attributable to Common Shareholders $ 2,765 $ 3,331 $ 3,308 Denominator (Units in Millions) : Average Common Shares Outstanding 766 796 857 Other Potentially Dilutive Common Shares 2 2 4 Average Common Shares Outstanding, Assuming Dilution 768 798 861 Net Earnings Per Share, Basic $ 3.61 $ 4.18 $ 3.86 Net Earnings Per Share, Assuming Dilution $ 3.60 $ 4.17 $ 3.84
Schedule of Average Outstanding Equity Awards Excluded from Diluted Earnings Per Share Calculation	The total average outstanding equity awards that were excluded from the diluted earnings per share calculation because their effect was antidilutive is in the table below. Fiscal Years 2020 2019 2018 Antidilutive stock options excluded from Diluted EPS (in millions) 2 1 —
Schedule of Share Repurchase Activity	During 2020, 2019, and 2018, CSX repurchased the following shares: Fiscal Years 2020 2019 2018 Shares Repurchased (Units in Millions) 13 48 72 Cost of Shares (Dollars in Millions) $ 867 $ 3,373 $ 4,671 Average Price Paid per Share $ 68.70 $ 70.54 $ 64.64

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
Shareholders' Equity (Tables)	Dec. 31, 2020
Stockholders' Equity Note [Abstract]
Schedule of Common and Preferred Stock	Common and preferred stock consists of the following: Common Stock, $1 Par Value December 2020 (Units in Millions) Common Shares Authorized 1,800 Common Shares Issued and Outstanding 763 Preferred Stock Preferred Shares Authorized 25 Preferred Shares Issued and Outstanding —

Stock Plans and Share-Based C_2

Stock Plans and Share-Based Compensation (Tables)	12 Months Ended
Stock Plans and Share-Based Compensation (Tables)	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Share-Based Compensation and Related Income Tax Benefit	Total pre-tax expense and income tax benefits associated with share-based compensation are shown in the table below. Income tax benefits include impacts from option exercises and the vesting of other equity awards. Fiscal Years (Dollars in Millions) 2020 2019 2018 Share-Based Compensation Expense Stock Options $ 19 $ 18 $ 13 Restricted Stock Units and Awards 6 8 6 Employee Stock Purchase Plan 5 4 2 Stock Awards for Directors 2 2 2 Performance Units (3) 42 28 Total Share-based Compensation Expense $ 29 $ 74 $ 51 Income Tax Benefit $ 19 $ 43 $ 26
Schedule of Assumptions and Inputs Used to Estimate Fair Value of Performance Units	The fair value of the performance units awarded during the years ended December 2020, 2019 and 2018 were calculated primarily using a Monte-Carlo simulation model with the following weighted-average assumptions: Weighted-average assumptions used: 2020 2019 2018 Annual dividend yield n/a 1.4 % 1.6 % Risk-free interest rate 1.4 % 2.4 % 2.3 % Annualized volatility 24.5 % 27.4 % 29.1 % Expected life (in years) 2.9 2.8 2.9
Schedule of Performance Unit Grant and Vesting Information	Performance unit grant and vesting information is summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 76.17 $ 66.18 $ 55.57 Fair value of units vested in fiscal year ending (in millions) $ 18 $ 17 $ 14
Schedule of Performance Unit Activity Related to Outstanding Long-term Incentive Plans and Corresponding Fair Value	The performance unit activity related to the outstanding long-term incentive plans and corresponding fair value is summarized as follows: Performance Units Outstanding Weighted-Average Fair Value at Grant Date Unvested at December 31, 2019 643 $ 60.58 Granted 356 76.17 Forfeited (34) 66.71 Vested (325) 55.35 Unvested at December 31, 2020 640 $ 71.59
Schedule of Assumptions and Inputs Used to Estimate Fair Value of Stock Options	Assumptions and inputs used to estimate fair value of stock options are summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 18.94 $ 17.87 $ 14.65 Stock options valuation assumptions: Annual dividend yield 1.2 % 1.3 % 1.5 % Risk-free interest rate 1.4 % 2.4 % 2.6 % Annualized volatility 26.1 % 25.7 % 27.0 % Expected life (in years) 6.0 6.1 6.5 Other pricing model inputs: Weighted-average grant-date market price of CSX stock (strike price) $ 79.58 $ 70.01 $ 54.19
Schedule of Stock Option Activity	The stock option activity is summarized as follows: Stock Options Outstanding Weighted-Average Exercise Price Weighted-Average Remaining Contractual Life Aggregate Intrinsic Value Outstanding at December 31, 2019 3,795 $ 49.78 Granted 1,339 79.58 Forfeited (131) 72.04 Exercised (786) 37.41 Outstanding at December 31, 2020 4,217 $ 60.88 7.5 $ 126 Exercisable at December 31, 2020 1,257 $ 40.05 6.0 $ 64
Schedule of Intrinsic Value and Cash Proceeds of Options Exercises	There were no significant exercises during 2018. Additional information on stock option exercises is summarized as follows: (Dollars in Millions) 2020 2019 Intrinsic value of stock options exercised $ 30 $ 87 Cash received from option exercises $ 29 $ 45
Schedule of Restricted Stock Grant and Vesting Information	Restricted stock grant and vesting information is summarized as follows: Fiscal Years 2020 2019 2018 Weighted-average grant date fair value $ 79.30 $ 69.19 $ 62.60 Fair value of units and awards vested during fiscal year ended (in millions) $ 8 $ 7 $ 9
Schedule of Outstanding Restricted Stock Units and Awards	The restricted stock activity related to the outstanding long-term incentive plans and other awards and corresponding fair value is summarized as follows: Restricted Stock Units and Awards Outstanding Weighted-Average Fair Value at Grant Date Unvested at December 31, 2019 427 $ 57.29 Granted 106 79.30 Forfeited (24) 63.12 Vested (157) 48.42 Unvested at December 31, 2020 352 $ 67.08
Schedule of Shares Issued under Employee Stock Purchase Plan	During 2019 and 2020, the Company issued the following shares under this program. Fiscal Years 2020 2019 Shares issued (in thousands) 242 249 Weighted average purchase price per share $ 60.40 $ 52.72

Casualty, Environmental and O_2

Casualty, Environmental and Other Reserves (Tables)	12 Months Ended
Casualty, Environmental and Other Reserves (Tables)	Dec. 31, 2020
Casualty, Environmental and Other Reserves [Abstract]
Schedule of Claims Activity	Activity related to casualty, environmental and other reserves is as follows: Casualty Environmental Other (Dollars in Millions) Reserves Reserves Reserves Total December 31, 2017 $ 228 $ 90 $ 56 $ 374 Charged to Expense 21 10 41 72 Payments (50) (20) (52) (122) December 31, 2018 199 80 45 324 Charged to Expense 56 17 34 107 Payments (68) (23) (35) (126) December 31, 2019 187 74 44 305 Charged to Expense 55 20 32 107 Payments (46) (18) (34) (98) December 31, 2020 $ 196 $ 76 $ 42 $ 314
Schedule of Balance Sheet Presentation of Casualty, Environmental and Other Reserves	Casualty, environmental and other reserves are provided for in the consolidated balance sheets as shown in the table below. December 2020 December 2019 (Dollars in Millions) Current Long-term Total Current Long-term Total Casualty: Personal Injury $ 38 $ 93 $ 131 $ 42 $ 87 $ 129 Occupational 11 54 65 6 52 58 Total Casualty $ 49 $ 147 $ 196 $ 48 $ 139 $ 187 Environmental 23 53 76 31 43 74 Other 18 24 42 21 23 44 Total $ 90 $ 224 $ 314 $ 100 $ 205 $ 305

Properties (Tables)

Properties (Tables)	12 Months Ended
Properties (Tables)	Dec. 31, 2020
Property, Plant and Equipment [Abstract]
Schedule of Net Properties	Details of the Company’s net properties are as follows: (Dollars in Millions) Accumulated Net Book Annual Depreciation Estimated Useful Life Depreciation December 2020 Cost Depreciation Value Rate ( Avg. Years) Method Road Rail and Other Track Material $ 8,449 $ (1,739) $ 6,710 2.5% 41 Group Life Ties 6,284 (1,780) 4,504 3.5% 28 Group Life Grading 2,768 (614) 2,154 1.3% 75 Group Life Ballast 3,238 (1,051) 2,187 2.6% 38 Group Life Bridges, Trestles, and Culverts 2,688 (380) 2,308 1.7% 60 Group Life Signals and Interlockers 3,170 (944) 2,226 4.1% 24 Group Life/ Straight Line (a) Buildings 1,366 (529) 837 2.5% 40 Group Life Other 5,146 (2,101) 3,045 4.1% 25 Group Life Total Road 33,109 (9,138) 23,971 Equipment Locomotive 5,085 (1,849) 3,236 3.6% 27 Group Life Freight Cars 2,557 (540) 2,017 2.9% 35 Group Life Work Equipment and Other 2,585 (1,559) 1,026 8.2% 12 Group Life/ Straight Line (a) Total Equipment 10,227 (3,948) 6,279 Land 1,823 — 1,823 N/A N/A N/A Construction In Progress 371 — 371 N/A N/A N/A Total Properties $ 45,530 $ (13,086) $ 32,444 (a) For depreciation method, certain asset categories contain intermodal terminals or technology-related assets, which are depreciated using the straight-line method. NOTE 6. Properties, continued (Dollars in Millions) Accumulated Net Book Annual Depreciation Estimated Useful Life Depreciation December 2019 Cost Depreciation Value Rate (Avg. Years) Method Road Rail and Other Track Material $ 8,194 $ (1,719) $ 6,475 2.5% 40 Group Life Ties 6,041 (1,666) 4,375 3.7% 27 Group Life Grading 2,763 (595) 2,168 1.4% 72 Group Life Ballast 3,156 (1,013) 2,143 2.7% 37 Group Life Bridges, Trestles, and Culverts 2,529 (334) 2,195 1.6% 61 Group Life Signals and Interlockers 3,077 (819) 2,258 4.0% 25 Group Life/ Straight Line (a) Buildings 1,335 (492) 843 2.5% 40 Group Life Other 5,030 (1,980) 3,050 4.2% 24 Group Life Total Road 32,125 (8,618) 23,507 Equipment Locomotive 5,320 (2,020) 3,300 3.6% 27 Group Life Freight Cars 2,964 (880) 2,084 2.9% 35 Group Life Work Equipment and Other 2,424 (1,414) 1,010 8.2% 12 Group Life/ Straight Line (a) Total Equipment 10,708 (4,314) 6,394 Land 1,836 — 1,836 N/A N/A N/A Construction In Progress 431 — 431 N/A N/A N/A Total Properties $ 45,100 $ (12,932) $ 32,168

Leases (Tables)

Leases (Tables)	12 Months Ended
Leases (Tables)	Dec. 31, 2020
Leases [Abstract]
Schedule of Amount, Timing and Uncertainty of Cash Flows of Company's Operating Leases	The following table presents information about the amount, timing and uncertainty of cash flows arising from all of the Company’s operating leases as of December 31, 2020. (Dollars in Millions) December 2020 Maturity of Lease Liabilities Lease Payments 2021 47 2022 43 2023 36 2024 36 2025 35 Thereafter 1,172 Total undiscounted operating lease payments $ 1,369 Less: Imputed interest (869) Present value of operating lease liabilities $ 500 (Dollars in Millions) Conrail Shared Years Asset Agreement 2021 $ 30 2022 30 2023 30 2024 22 2025 — Thereafter — Total $ 112
Schedule of Balance Sheet Classification and Other Information of Company's Operating Leases	(Dollars in Millions) 2020 2019 Balance Sheet Classification Right of use asset $ 472 $ 532 Current lease liabilities (recorded in other current liabilities) $ 45 $ 57 Long-term lease liabilities 455 493 Total operating lease liabilities $ 500 $ 550 Other Information Weighted-average remaining lease term for operating leases 35 years 33 years Weighted-average discount rate for operating leases 5.0 % 5.0 %
Schedule of Operating Lease Costs	These amounts are shown in the table below. Fiscal Years (Dollars in Millions) 2020 2019 2018 Rent Expense on Operating Leases $ 82 $ 84 $ 66

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of Number of Locomotives and Payments under Long-term Maintenance Program	The following table summarizes the number of locomotives covered and CSXT’s payments under the long-term maintenance program. Fiscal Years (Dollars in Millions) 2020 2019 2018 Amounts Paid $ 158 $ 139 $ 170 Number of Locomotives 1,874 1,897 1,910
Schedule of Annual Payments under Long-term Maintenance Program	Total annual payments under all of these purchase commitments are also estimated in the table below. (Dollars in Millions) Locomotive Maintenance & Rebuild Payments Other Total 2021 $ 195 $ 39 $ 234 2022 204 22 226 2023 228 20 248 2024 270 14 284 2025 284 14 298 Thereafter 1,892 93 1,985 Total $ 3,073 $ 202 $ 3,275

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
Employee Benefit Plans (Tables)	Dec. 31, 2020
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]
Summary of Participants	In order to perform this valuation, the actuaries are provided with the details of the population covered at the beginning of the year, summarized in the table below, and projects that population forward to the end of the year. Summary of Participants as of January 1, 2020 Pension Plans Post-retirement Medical Plan Active Employees 3,373 779 Retirees and Beneficiaries 11,841 2,282 Other (a) 3,854 — Total 19,068 3,061
Schedule of Future Expected Benefit Payments	Future expected benefit payments are as follows: Expected Cash Flows (Dollars in Millions) Pension Benefits Post-retirement Benefits 2021 $ 196 $ 17 2022 188 10 2023 187 9 2024 186 8 2025 185 8 2026-2030 898 28 Total $ 1,840 $ 80
Schedule of Allocation of Plan Assets	The distribution of pension plan assets as of the measurement date is shown in the table below, and these assets are reported net of pension liabilities on the balance sheet. December 2020 December 2019 Percent of Percent of (Dollars in Millions) Amount Total Assets Amount Total Assets Growth-Oriented $ 1,816 61 % $ 2,027 72 % Equity 1,324 44 1,772 63 Fixed Income 271 9 229 8 Cash and Cash Equivalents 221 8 26 1 Immunizing 1,184 39 798 28 Fixed Income 1,018 34 595 21 Cash and Cash Equivalents 166 5 203 7 Total $ 3,000 100 % $ 2,825 100 %
Schedule of Changes in Benefit Obligation and Fair Value of Plan Assets	Changes in benefit obligation and the fair value of plan assets for the 2020 and 2019 calendar plan years are as follows: Pension Benefits Post-retirement Benefits Plan Year Plan Year Plan Year Plan Year (Dollars in Millions) 2020 2019 2020 2019 Actuarial Present Value of Benefit Obligation Accumulated Benefit Obligation $ 3,134 $ 2,963 N/A N/A Projected Benefit Obligation 3,257 3,122 $ 96 $ 117 Change in Projected Benefit Obligation: Projected Benefit Obligation at Beginning of Plan Year $ 3,122 $ 2,758 $ 117 $ 118 Service Cost (a) 46 34 1 1 Interest Cost 82 103 5 2 Plan Participants' Contributions — — 6 7 Actuarial Loss (Gain) 197 418 (11) 22 Benefits Paid (190) (191) (22) (33) Benefit Obligation at End of Plan Year $ 3,257 $ 3,122 $ 96 $ 117 Change in Plan Assets: Fair Value of Plan Assets at Beginning of Plan Year $ 2,825 $ 2,431 $ — $ — Actual Return on Plan Assets 345 568 — — Non-qualified Employer Contributions 20 17 16 26 Plan Participants' Contributions — — 6 7 Benefits Paid (190) (191) (22) (33) Fair Value of Plan Assets at End of Plan Year 3,000 2,825 — — Funded Status at End of Plan Year $ (257) $ (297) $ (96) $ (117) (a) Service cost for each 2020 and 2019 includes capitalized service costs of $3 million.
Schedule of Amount Recognized in Balance Sheet	Amounts related to pension and post-retirement benefits recorded in other long-term assets, labor and fringe benefits payable and other long-term liabilities on the balance sheet are as follows: Pension Benefits Post-retirement Benefits December December December December (Dollars in Millions) 2020 2019 2020 2019 Amounts Recorded in Consolidated Balance Sheets: Long-term Assets (a) $ 29 $ 25 $ — $ — Current Liabilities (16) (17) (17) (20) Long-term Liabilities (270) (305) (79) (97) Net Amount Recognized in Consolidated Balance Sheets $ (257) $ (297) $ (96) $ (117)
Schedule of Benefit Obligations in Excess of Plan Assets	At December 2020, the status of CSX plans with a net liability only is disclosed below. The total fair value of all plan assets as of December 2020 was $3.0 billion, which includes the qualified pension plans with net assets. Aggregate (Dollars in Millions) Fair Value Aggregate Benefit Obligations in Excess of Plan Assets of Plan Assets Benefit Obligation Projected Benefit Obligation $ 2,884 $ (3,170) Accumulated Benefit Obligation 2,884 (264)
Schedule of Net Benefit Expense	The following table describes the components of expense/(income) related to net benefit expense recorded on the income statement. Pension Benefits Post-retirement Benefits (Dollars in Millions) 2020 2019 2018 2020 2019 2018 Service Cost Included in Labor and Fringe $ 43 $ 31 $ 32 $ 1 $ 1 $ 2 Interest Cost 82 103 92 5 2 7 Expected Return on Plan Assets (176) (171) (176) — — — Amortization of Net Loss 54 30 41 1 — — Amortization of Prior Service Cost — — — (7) (7) (2) Total (Income)/ Expense Included in Other Income - Net (40) (38) (43) (1) (5) 5 Net Periodic Benefit Cost/(Credit) $ 3 $ (7) $ (11) $ — $ (4) $ 7 Settlement Gain (1) — (1) — — — Total Periodic Benefit Cost/(Credit) $ 2 $ (7) $ (12) $ — $ (4) $ 7
Schedule of Pre-tax Change in Other Comprehensive Loss (Income)	The following table shows the pre-tax change in other comprehensive loss (income) attributable to certain components of net benefit expense and the change in benefit obligation for CSX for pension and other post-employment benefits. (Dollars in Millions) Pension Benefits Post-retirement Benefits Components of Other Comprehensive December December December December Loss (Income) 2020 2019 2020 2019 Recognized in the Balance Sheet Losses (Gains) $ 28 $ 21 $ (11) $ 22 Expense (Income) Recognized in the Income Statement Amortization of Net Losses $ 54 $ 30 $ 1 $ — Settlement Gain (1) — — — Amortization of Prior Service Costs — — (7) (7)
Schedule of Weighted-Average Assumptions Used	The weighted averages of assumptions used by the Company to value its pension and post-retirement obligations were as follows: Pension Benefits Post-retirement Benefits 2020 2019 2020 2019 Expected Long-term Return on Plan Assets: Benefit Cost for Current Plan Year 6.75 % 6.75 % N/A N/A Benefit Cost for Subsequent Plan Year 6.75 % 6.75 % N/A N/A Discount Rates: Benefit Cost for Plan Year Service Cost for Plan Year 3.32 % 4.40 % 2.93 % 4.14 % Interest Cost for Plan Year 2.69 % 3.87 % 2.43 % 3.51 % Benefit Obligation at End of Plan Year 2.43 % 3.13 % 2.07 % 2.87 % Salary Scale Inflation 4.60 % 4.60 % N/A N/A Cash Balance Plan Interest Credit Rate 3.75 % 3.75 % N/A N/A

Debt and Credit Agreements (Tab

Debt and Credit Agreements (Tables)	12 Months Ended
Debt and Credit Agreements (Tables)	Dec. 31, 2020
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments	Debt at December 2020 and December 2019 is shown in the table below. For information regarding the fair value of debt, see Note 13, Fair Value Measurements. Maturity at Average December December (Dollars in Millions) 2020 2020 2020 2019 Notes 2021-2068 4.0% $ 16,542 $ 16,056 Equipment Obligations (a) 2021-2023 6.3% 160 178 Finance Leases 2020-2026 14.5% 3 4 Subtotal Long-term Debt (including current portion) $ 16,705 $ 16,238 Less Debt Due within One Year (401) (245) Long-term Debt (excluding current portion) $ 16,304 $ 15,993 (a) Equipment obligations are secured by an interest in certain railroad equipment.
Schedule of Long-term Debt Maturities	Long-term Debt Maturities (Net of Discounts, Premiums and Issuance Costs) (Dollars in Millions) Maturities at Fiscal Years Ending December 2020 2021 $ 401 2022 162 2023 139 2024 551 2025 601 Thereafter 14,851 Total Long-term Debt Maturities, including current portion $ 16,705

Revenues (Tables)

Revenues (Tables)	12 Months Ended
Revenues (Tables)	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of Revenues Disaggregated by Lines of Business	The following table presents the Company’s revenues disaggregated by market as this best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Fiscal Years (Dollars in millions) 2020 2019 2018 Chemicals (a) $ 2,309 $ 2,349 $ 2,344 Agricultural and Food Products 1,386 1,410 1,306 Automotive 920 1,236 1,267 Forest Products (a) 824 862 834 Metals and Equipment (a) 675 742 771 Minerals (a) 538 559 527 Fertilizers 424 431 442 Total Merchandise 7,076 7,589 7,491 Intermodal 1,702 1,760 1,931 Coal 1,397 2,070 2,246 Other 408 518 582 Total $ 10,583 $ 11,937 $ 12,250
Schedule of Accounts Receivable, Net	The Company’s accounts receivable - net consists of freight and non-freight receivables, reduced by an allowance for credit losses. (Dollars in millions) December 31, December 31, Freight Receivables $ 716 $ 790 Freight Allowance for Credit Losses (16) (21) Freight Receivables, net 700 769 Non-Freight Receivables 224 226 Non-Freight Allowance for Credit Losses (12) (9) Non-Freight Receivables, net 212 217 Total Accounts Receivable, net $ 912 $ 986

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
Income Taxes (Tables)	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of Breakdown of Income Tax Expense Between Current and Deferred	The breakdown of income tax expense between current and deferred is as follows: Fiscal Years (Dollars in Millions) 2020 2019 2018 Current: Federal $ 559 $ 608 $ 572 State 123 104 144 Subtotal Current 682 712 716 Deferred: Federal 149 235 275 State 31 38 4 Subtotal Deferred 180 273 279 Total Income Tax Expense $ 862 $ 985 $ 995
Schedule of Income Tax Expense Reconciled to Tax Computed at Statutory Rates	Income tax expense reconciled to the tax computed at statutory rates is presented in the following table. Fiscal Years (Dollars In Millions) 2020 2019 2018 Federal Income Taxes $ 762 21.0 % $ 906 21.0 % $ 904 21.0 % State Income Taxes 117 3.2 % 108 2.5 % 112 2.6 % Other (17) (0.4) % (29) (0.7) % (21) (0.5) % Income Tax Expense/ Rate $ 862 23.8 % $ 985 22.8 % $ 995 23.1 %
Schedule of Significant Components of Deferred Income Tax Assets and Liabilities	The significant components of deferred income tax assets and liabilities include: 2020 2019 (Dollars in Millions) Assets Liabilities Assets Liabilities Pension Plans $ 62 $ — $ 71 $ — Other Employee Benefit Plans 96 — 127 — Accelerated Depreciation — 7,195 — 7,020 Other 320 451 426 565 Total $ 478 $ 7,646 $ 624 $ 7,585 Net Deferred Income Tax Liabilities $ 7,168 $ 6,961

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
Fair Value Measurements (Tables)	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Investment Assets	The Company's investment assets are carried at fair value on the consolidated balance sheets as summarized in the following table. All of the inputs used to determine the fair value of the Company's investments are Level 2 inputs. Fiscal Years 2020 2019 (Dollars in Millions) Level 2 Level 2 Corporate Bonds $ 68 $ 59 Government Securities 33 36 Commercial Paper and Certificates of Deposit — 989 Total investments at fair value $ 101 $ 1,084 Total investments at amortized cost $ 89 $ 1,076
Schedule of Investment Maturities	These investments have the following maturities and are represented on the consolidated balance sheet within short-term investments for investments with maturities of less than one year, and other long-term assets for investments with maturities of one year and greater. (Dollars in Millions) December 2020 December 2019 Less than 1 year $ 2 $ 996 1 - 5 years 22 10 5 - 10 years 23 25 Greater than 10 years 54 53 Total investments at fair value $ 101 $ 1,084
Schedule of Fair Value and Carrying Value of Long-term Debt	The fair value and carrying value of the Company's long-term debt is as follows: (Dollars in Millions) December 2020 December 2019 Long-term Debt (Including Current Maturities): Fair Value $ 21,076 $ 18,503 Carrying Value 16,705 16,238
Schedule of Pension Plan Assets at Fair Value by Level	The pension plan assets at fair value by level, within the fair value hierarchy, as of calendar plan years 2020 and 2019 are shown in the table below. For additional information related to pension assets, see Note 9, Employee Benefit Plans. Fiscal Years 2020 2019 (Dollars in Millions) Level 1 Level 2 Total Level 1 Level 2 Total Common Stock $ 337 $ — $ 337 $ 823 $ — $ 823 Mutual funds 21 — 21 78 — 78 Cash and cash equivalents 387 — 387 229 — 229 Corporate bonds — 1,026 1,026 — 588 588 Government securities — 164 164 — 217 217 Asset-backed securities, derivatives and other — 85 85 — 17 17 Total investments in the fair value hierarchy $ 745 $ 1,275 $ 2,020 $ 1,130 $ 822 $ 1,952 Investments measured at net asset value (a) n/a n/a $ 980 n/a n/a $ 873 Investments at fair value $ 745 $ 1,275 $ 3,000 $ 1,130 $ 822 $ 2,825

Other Income - Net (Tables)

Other Income - Net (Tables)	12 Months Ended
Other Income - Net (Tables)	Dec. 31, 2020
Other Income and Expenses [Abstract]
Schedule of Other Income - Net	Other income – net consisted of the following: Fiscal Years (Dollars in Millions) 2020 2019 2018 Net Periodic Pension and Post-retirement Benefit Credit (a) $ 42 $ 43 $ 38 Interest Income 17 48 32 Debt Repurchase Expense (48) (10) — Miscellaneous Income 8 7 4 Total Other Income - Net $ 19 $ 88 $ 74

Investment in Affiliates and _2

Investment in Affiliates and Related-Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Schedule of Equity-method Investments in Affiliates	CSX's investments in affiliates are included on the consolidated balance sheet as investments in affiliates and other companies. December December (Dollars in Millions) 2020 2019 Equity-method investments: Conrail $ 1,025 $ 982 TTX 796 743 Other 164 154 Total $ 1,985 $ 1,879
Schedule of Future Payments Under Shared Asset Area Agreements	The following table presents information about the amount, timing and uncertainty of cash flows arising from all of the Company’s operating leases as of December 31, 2020. (Dollars in Millions) December 2020 Maturity of Lease Liabilities Lease Payments 2021 47 2022 43 2023 36 2024 36 2025 35 Thereafter 1,172 Total undiscounted operating lease payments $ 1,369 Less: Imputed interest (869) Present value of operating lease liabilities $ 500 (Dollars in Millions) Conrail Shared Years Asset Agreement 2021 $ 30 2022 30 2023 30 2024 22 2025 — Thereafter — Total $ 112
Schedule of Related Party in the Consolidated Income Statement Components	The following table discloses amounts related to Conrail. All amounts in the table below are included in materials, supplies and other expenses on the Company’s consolidated income statements. Fiscal Years (Dollars in Millions) 2020 2019 2018 Rents, fees and services $ 126 $ 119 $ 117 Purchase price amortization and other 4 4 4 Equity earnings of Conrail (49) (42) (43) Total Conrail Expense $ 81 $ 81 $ 78 Related Party Disclosures Topic in the ASC, the following table discloses amounts related to TTX. Car hire rents and equity earnings are included in equipment and other rents expense on the Company’s consolidated income statement. Fiscal Years (Dollars in Millions) 2020 2019 2018 Income statement information: Car hire rents $ 219 $ 223 $ 223 Equity earnings of TTX (51) (56) (60) Total TTX expense $ 168 $ 167 $ 163
Schedule of Related Party Consolidated Balance Sheet Components	As required by the Related Party Disclosures Topic in the ASC, the Company has identified amounts below owed to Conrail, or its subsidiaries, representing liabilities under the operating, equipment and shared area agreements with Conrail. In 2014, the Company executed two promissory notes with a subsidiary of Conrail which were included in long-term debt on the consolidated balance sheets. Interest expense from these promissory notes was $6 million in each 2020, 2019 and 2018. December December (Dollars in Millions) 2020 2019 Balance Sheet Information: CSX accounts payable to Conrail $ 50 $ 213 Promissory notes payable to Conrail subsidiary 1.31% CSX Promissory Note due December 2050 73 — 1.31% CSXT Promissory Note due December 2050 368 — 2.89% CSX Promissory Note due October 2044 — 73 2.89% CSXT Promissory Note due October 2044 — 151 Also included below is balance sheet information related to CSX's payable to TTX, which represents car rental liabilities. December December Balance sheet information: 2020 2019 CSX payable to TTX $ 40 $ 34

Other Comprehensive Income _ _2

Other Comprehensive Income / (Loss) (Tables)	12 Months Ended
Other Comprehensive Income / (Loss) (Tables)	Dec. 31, 2020
Equity [Abstract]
Schedule of Changes in the AOCI Balance by Component	Changes in the AOCI balance by component are shown in the following table. Amounts reclassified in pension and other post-employment benefits to net earnings relate to the amortization of actuarial losses and are included in other income-net on the consolidated income statements. See Note 9. Employee Benefit Plans for further information. Interest rate derivatives consist of forward starting interest rate swaps classified as cash flow hedges. See Note 10, Debt and Credit Agreements for further information. Other primarily represents CSX's share of AOCI of equity method investees. Amounts reclassified in other to net earnings are included in materials, supplies, and other or equipment and other rents on the consolidated income statements. Pension and Other Post-Employment Benefits Interest Rate Derivatives Other Accumulated Other Comprehensive Income (Loss) (Dollars in millions) Balance December 31, 2017 - Net of Tax $ (440) $ — $ (46) $ (486) Other Comprehensive Income (Loss) Reclassification of Stranded Tax Effects (a) (108) — 1 (107) Loss Before Reclassifications (111) — (8) (119) Amounts Reclassified to Net Earnings 38 — (6) 32 Tax Benefit 17 — 2 19 Total Other Comprehensive Loss (164) — (11) (175) Balance December 31, 2018 - Net of Tax (604) — (57) (661) Other Comprehensive Income (Loss) Loss Before Reclassifications (43) — (5) (48) Amounts Reclassified to Net Earnings 23 — 8 31 Tax Benefit (Expense) 5 — (2) 3 Total Other Comprehensive (Loss) Income (15) — 1 (14) Balance December 31, 2019 - Net of Tax (619) — (56) (675) Other Comprehensive Income (Loss) (Loss) Income Before Reclassifications (17) 80 (10) 53 Amounts Reclassified to Net Earnings 47 — 5 52 Tax Expense (9) (18) (1) (28) Total Other Comprehensive Income (Loss) 21 62 (6) 77 Balance December 31, 2020 - Net of Tax $ (598) $ 62 $ (62) $ (598)

Nature of Operations and Sign_3

Nature of Operations and Significant Accounting Policies (Details) carload in Thousands, $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2020USD ($)mi	Dec. 31, 2020USD ($)employeeterminalline_of_businessrailroadcarloadport_terminalstatemi	Dec. 31, 2019USD ($)	[1]	Dec. 31, 2018USD ($)	[1]
Revenue from External Customer [Line Items]
Number of rail route miles \| mi		19,500
Rail network states number \| state		23
Number of ocean, river and lake ports serviced (over) \| port_terminal		70
Number of short-line and regional railroads served (more than) \| railroad		230
Revenue \| $		$ 10,583	$ 11,937		$ 12,250
Number of primary lines of business \| line_of_business		3
Number of employees \| employee		19,300
Number of union employees \| employee		15,700
Cost method, maximum percentage		20.00%
Pan Am
Revenue from External Customer [Line Items]
Number of rail route miles \| mi	1,200
Number of partial interests in rail route miles \| mi	600
Pan Am
Revenue from External Customer [Line Items]
Deposit paid to acquire business classified as other investing activities \| $	$ 30
Merchandise business
Revenue from External Customer [Line Items]
Number of carloads \| carload		2,500
Percentage of total volume		43.00%
Percentage of total revenue		67.00%
Intermodal business
Revenue from External Customer [Line Items]
Number of carloads \| carload		2,700
Percentage of total volume		46.00%
Percentage of total revenue		16.00%
Number of terminals \| terminal		30
Coal business
Revenue from External Customer [Line Items]
Number of carloads \| carload		637
Percentage of total volume		11.00%
Percentage of total revenue		13.00%
Other business
Revenue from External Customer [Line Items]
Percentage of total revenue		4.00%

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Numerator:
Net Earnings	$ 2,765	$ 3,331	[1]	$ 3,309	[1]
Dividend Equivalents on Restricted Stock	0	0		(1)
Net Earnings, Attributable to Common Shareholders	$ 2,765	$ 3,331		$ 3,308
Denominator:
Average Common Shares Outstanding (in shares)	766	796	[1]	857	[1]
Other Potentially Dilutive Common Shares (in shares)	2	2		4
Average Common Shares Outstanding, Assuming Dilution (in shares)	768	798	[1]	861	[1]
Earnings Per Share, Basic (in dollars per share)	$ 3.61	$ 4.18	[1]	$ 3.86	[1]
Net Earnings Per Share, Assuming Dilution (in dollars per share)	$ 3.60	$ 4.17	[1]	$ 3.84	[1]

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Earnings Per Share - Antidiluti

Earnings Per Share - Antidilutive Stock Options Excluded from Diluted Earnings Per Share Calculation (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities (in shares)	2	1	0

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) shares in Millions	Oct. 17, 2019USD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)agreementshares	Oct. 21, 2020USD ($)	Sep. 30, 2019shares	Aug. 31, 2019USD ($)	Jan. 31, 2019USD ($)	Feb. 28, 2018USD ($)	Oct. 31, 2017USD ($)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase program, remaining amount		$ 5,900,000,000	$ 5,900,000,000
Number of shares repurchased (in shares) \| shares			13	48	72
Amount of shares repurchased			$ 867,000,000	$ 3,373,000,000	$ 4,671,000,000
January 2019 program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase program authorized amount									$ 5,000,000,000
Share repurchase program, remaining amount		$ 889,000,000	889,000,000
Number of shares repurchased (in shares) \| shares		1.1
Accelerated share repurchase program payment		$ 100,000,000	$ 100,000,000					$ 250,000,000
Accelerated share repurchase program initial shares received (in shares) \| shares							4
January 2019 program \| Affiliated Entity \| MR Argent Advisor LLC
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares repurchased (in shares) \| shares	4.7
Amount of shares repurchased	$ 319,000,000
October 2020 program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase program authorized amount						$ 5,000,000,000
October 2017 program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase program authorized amount										$ 5,000,000,000	$ 1,500,000,000
Number of shares repurchased (in shares) \| shares					22
Accelerated share repurchase program payment					$ 1,500,000,000
Number of accelerated share repurchase agreements entered into by the Company \| agreement					4

Earnings Per Share - Share Repu

Earnings Per Share - Share Repurchase Activity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Stock repurchased (in shares)	13	48	72
Cost of Shares	$ 867	$ 3,373	$ 4,671
Average Price Paid per Share (in dollars per share)	$ 68.70	$ 70.54	$ 64.64

Shareholders' Equity (Details)

Shareholders' Equity (Details) - $ / shares shares in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Common Stock, Par Value (in dollars per share)	$ 1	$ 1
Common Shares Authorized (in shares)	1,800
Common Shares Issued (in shares)	763
Common Shares Outstanding (in shares)	763
Preferred Shares Authorized (in shares)	25
Preferred Shares Issued (in shares)	0
Preferred Shares Outstanding (in shares)	0
Common stock, number of votes per share	$ 1

Stock Plans and Share-Based C_3

Stock Plans and Share-Based Compensation - Share-Based Compensation and Related Income Tax Benefit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	$ 29	$ 74	$ 51
Income Tax Benefit	19	43	26
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	19	18	13
Restricted Stock Units and Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	6	8	6
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	5	4	2
Stock Awards for Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	2	2	2
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Share-based Compensation Expense	$ (3)	$ 42	$ 28

Stock Plans and Share-Based C_4

Stock Plans and Share-Based Compensation - Narrative (Details)	8 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2020USD ($)planshares	Dec. 31, 2019	Dec. 31, 2018	May 31, 2018USD ($)shares
Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 2,000,000
Expected weighted average period of recognition for unrecognized compensation cost (in years)		1 year
Look-back period		2 years 10 months 24 days	2 years 9 months 18 days	2 years 10 months 24 days
Restricted Stock Units and Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 9,000,000
Expected weighted average period of recognition for unrecognized compensation cost (in years)		2 years
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		5 years
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost		$ 18,000,000
Expected weighted average period of recognition for unrecognized compensation cost (in years)		2 years
Look-back period		6 years	6 years 1 month 6 days	6 years 6 months
Non-management Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual retainer to be paid to non-management directors, common stock option		$ 162,500
Chairman
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual grant of common stock amount		$ 250,000
LITP \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range (as a percent)		0.00%
LITP \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Payout range (as a percent)		200.00%
LITP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equivalent shares of CSX common stock per unit of award (in shares) \| shares		1
Award performance period		3 years
Number of long term incentive plans \| plan		3
LITP \| Restricted Stock Units and Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit equivalent of CSX stock (in shares) \| shares		1
LITP \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance unit equivalent of CSX stock (in shares) \| shares		1
LITP \| Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award term		10 years
LITP \| Stock Options \| Vesting on anniversary of the grant date (graded period)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years	3 years
LITP \| Stock Options \| Vesting after the grant date (cliff period)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years	3 years	3 years
2020-2022 LTIP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years
Percentage payout on operating ratio		50.00%
2020-2022 LTIP \| Certain Executive Officers \| Performance Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		25.00%
2020-2022 LTIP \| Certain Executive Officers \| Performance Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		250.00%
2019-2021 LTIP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years
Percentage payout on operating ratio		50.00%
2019-2021 LTIP \| Certain Executive Officers \| Performance Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		25.00%
2019-2021 LTIP \| Certain Executive Officers \| Performance Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		250.00%
2018-2020 LTIP \| Performance Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award performance period		3 years
Percentage payout on operating ratio		50.00%
2018-2020 LTIP \| Certain Executive Officers \| Performance Units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		25.00%
2018-2020 LTIP \| Certain Executive Officers \| Performance Units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of payout subject to adjustment		200.00%
Non-management Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual retainer to be paid to non-management directors, cash option		$ 112,500
ESPP \| Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of registered shares of common stock that my be issued pursuant to plan (in shares) \| shares					4,000,000
Employee contribution percentage, minimum					1.00%
Employee contribution percentage, maximum					10.00%
Maximum value of stocks purchased by employee, after tax					$ 25,000
Percentage of share closing market price	85.00%
Share offering period	6 months

Stock Plans and Share-Based C_5

Stock Plans and Share-Based Compensation - Assumptions Used to Estimate Fair Value of Performance Units (Details) - Performance Units	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual dividend yield		1.40%	1.60%
Risk-free interest rate	1.40%	2.40%	2.30%
Annualized volatility	24.50%	27.40%	29.10%
Expected life (in years)	2 years 10 months 24 days	2 years 9 months 18 days	2 years 10 months 24 days

Stock Plans and Share-Based C_6

Stock Plans and Share-Based Compensation - Performance Unit Grant and Vesting Information (Details) - Performance Units - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in dollars per share)	$ 76.17	$ 66.18	$ 55.57
Fair value of units vested in fiscal year ending (in millions)	$ 18	$ 17	$ 14

Stock Plans and Share-Based C_7

Stock Plans and Share-Based Compensation - Performance Unit Activity Related to Outstanding Long-term Incentive Plans and Corresponding Fair Value (Details) - Performance Units shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Weighted-Average Fair Value at Grant Date
Unvested at December 31, 2019 (in dollars per share)	$ 66.18
Unvested at December 31, 2020 (in dollars per share)	$ 76.17
Long-term Incentive Plans
Units Outstanding
Unvested at December 31, 2019 (in shares) \| shares	643
Granted (in shares) \| shares	356
Forfeited (in shares) \| shares	(34)
Vested (in shares) \| shares	(325)
Unvested at December 31, 2020 (in shares) \| shares	640
Weighted-Average Fair Value at Grant Date
Unvested at December 31, 2019 (in dollars per share)	$ 60.58
Granted (in dollars per share)	76.17
Forfeited (in dollars per share)	66.71
Vested (in dollars per share)	55.35
Unvested at December 31, 2020 (in dollars per share)	$ 71.59

Stock Plans and Share-Based C_8

Stock Plans and Share-Based Compensation - Assumptions and Inputs Used to Estimate Fair Value of Stock Options (Details) - Stock Options - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in dollars per share)	$ 18.94	$ 17.87	$ 14.65
Annual dividend yield	1.20%	1.30%	1.50%
Risk-free interest rate	1.40%	2.40%	2.60%
Annualized volatility	26.10%	25.70%	27.00%
Expected life (in years)	6 years	6 years 1 month 6 days	6 years 6 months
Weighted-average grant-date market price of CSX stock (strike price) (in dollars per share)	$ 79.58	$ 70.01	$ 54.19

Stock Plans and Share-Based C_9

Stock Plans and Share-Based Compensation - Stock Option Activity (Details) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)$ / sharesshares
Stock Options Outstanding
Outstanding at December 31, 2019 (in shares) \| shares	3,795
Granted (in shares) \| shares	1,339
Forfeited (in shares) \| shares	(131)
Exercised (in shares) \| shares	(786)
Outstanding at December 31, 2020 (in shares) \| shares	4,217
Exercisable at December 31, 2020 (in shares) \| shares	1,257
Weighted-Average Exercise Price
Outstanding at December 31, 2019 (in dollars per share) \| $ / shares	$ 49.78
Granted (in dollars per share) \| $ / shares	79.58
Forfeited (in dollars per share) \| $ / shares	72.04
Exercised (in dollars per share) \| $ / shares	37.41
Outstanding at December 31, 2020 (in dollars per share) \| $ / shares	60.88
Exercisable at December 31, 2020 (in dollars per share) \| $ / shares	$ 40.05
Outstanding at December 31, 2020, Weighted-average remaining contractual life (in years)	7 years 6 months
Exercisable at December 31, 2020, Weighted-average remaining contractual life (in years)	6 years
Outstanding at December 31, 2020, Aggregate intrinsic value \| $	$ 126
Exercisable at December 31, 2020, Aggregate intrinsic value \| $	$ 64

Stock Plans and Share-Based _10

Stock Plans and Share-Based Compensation - Intrinsic Value and Cash Received on Exercises (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Intrinsic value of stock options exercised	$ 30	$ 87
Cash received from option exercises	$ 29	$ 45

Stock Plans and Share-Based _11

Stock Plans and Share-Based Compensation - Restricted Stock Grant and Vesting Information (Details) - Restricted Stock Units and Awards - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant date fair value (in dollars per share)	$ 79.30	$ 69.19	$ 62.60
Fair value of units vested in fiscal year ending (in millions)	$ 8	$ 7	$ 9

Stock Plans and Share-Based _12

Stock Plans and Share-Based Compensation - Outstanding Restricted Stock Units and Award (Details) - Restricted Stock Units and Awards shares in Thousands	12 Months Ended
	Dec. 31, 2020$ / sharesshares
Units Outstanding
Unvested at December 31, 2019 (in shares) \| shares	427
Granted (in shares) \| shares	106
Forfeited (in shares) \| shares	(24)
Vested (in shares) \| shares	(157)
Unvested at December 31, 2020 (in shares) \| shares	352
Weighted-Average Fair Value at Grant Date
Unvested at December 31, 2019 (in dollars per share) \| $ / shares	$ 57.29
Granted (in dollars per share) \| $ / shares	79.30
Forfeited (in dollars per share) \| $ / shares	63.12
Vested (in dollars per share) \| $ / shares	48.42
Unvested at December 31, 2020 (in dollars per share) \| $ / shares	$ 67.08

Stock Plans and Share-Based _13

Stock Plans and Share-Based Compensation - Shares Issued Under Employee Stock Purchase Plan (Details) - Stock Awards for Directors - Employee Stock - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	242	249
Weighted average purchase price per share (in dollars per share)	$ 60.40	$ 52.72

Casualty, Environmental and O_3

Casualty, Environmental and Other Reserves - Schedule of Claims Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	$ 305	$ 324	$ 374
Charged to Expense	107	107	72
Payments	(98)	(126)	(122)
Balance end of period	314	305	324
Casualty Reserves
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	187	199	228
Charged to Expense	55	56	21
Payments	(46)	(68)	(50)
Balance end of period	196	187	199
Environmental Reserves
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	74	80	90
Charged to Expense	20	17	10
Payments	(18)	(23)	(20)
Balance end of period	76	74	80
Other Reserves
Loss Contingency Accrual [Roll Forward]
Balance at beginning of period	44	45	56
Charged to Expense	32	34	41
Payments	(34)	(35)	(52)
Balance end of period	$ 42	$ 44	$ 45

Casualty, Environmental and O_4

Casualty, Environmental and Other Reserves - Balance Sheet Presentation (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018	Dec. 31, 2017
Contingencies [Line Items]
Current	$ 90	$ 100	[1]
Long-term	224	205	[1]
Total	314	305		$ 324	$ 374
Casualty
Contingencies [Line Items]
Current	49	48
Long-term	147	139
Total	196	187		199	228
Personal Injury
Contingencies [Line Items]
Current	38	42
Long-term	93	87
Total	131	129
Occupational
Contingencies [Line Items]
Current	11	6
Long-term	54	52
Total	65	58
Environmental
Contingencies [Line Items]
Current	23	31
Long-term	53	43
Total	76	74		80	90
Other
Contingencies [Line Items]
Current	18	21
Long-term	24	23
Total	$ 42	$ 44		$ 45	$ 56

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Casualty, Environmental and O_5

Casualty, Environmental and Other Reserves - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)claimsite	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Loss Contingencies [Line Items]
Reserves	$ 314	$ 305	$ 324	$ 374
Casualty Reserves
Loss Contingencies [Line Items]
Reserves	$ 196	187	199	228
Individual claims expected to exceed self-insured retention amount \| claim	0
Casualty Reserves \| Maximum
Loss Contingencies [Line Items]
Self-insured retention amount per injury	$ 75
Personal Injury
Loss Contingencies [Line Items]
Reserves	131	129
Environmental
Loss Contingencies [Line Items]
Reserves	$ 76	74	80	90
Environmental impaired sites \| site	220
Other
Loss Contingencies [Line Items]
Reserves	$ 42	$ 44	$ 45	$ 56

Properties - Schedule of Net Pr

Properties - Schedule of Net Properties (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 45,530	$ 45,100	[1]
Accumulated Depreciation	(13,086)	(12,932)	[1]
Properties - Net (Note 6)	32,444	32,168	[1]
Total Road
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	33,109	32,125
Accumulated Depreciation	(9,138)	(8,618)
Properties - Net (Note 6)	23,971	23,507
Rail and Other Track Material
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	8,449	8,194
Accumulated Depreciation	(1,739)	(1,719)
Properties - Net (Note 6)	$ 6,710	$ 6,475
Annual Depreciation Rate	2.50%	2.50%
Estimated useful life (Avg. Years)	41 years	40 years
Ties
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 6,284	$ 6,041
Accumulated Depreciation	(1,780)	(1,666)
Properties - Net (Note 6)	$ 4,504	$ 4,375
Annual Depreciation Rate	3.50%	3.70%
Estimated useful life (Avg. Years)	28 years	27 years
Grading
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,768	$ 2,763
Accumulated Depreciation	(614)	(595)
Properties - Net (Note 6)	$ 2,154	$ 2,168
Annual Depreciation Rate	1.30%	1.40%
Estimated useful life (Avg. Years)	75 years	72 years
Ballast
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 3,238	$ 3,156
Accumulated Depreciation	(1,051)	(1,013)
Properties - Net (Note 6)	$ 2,187	$ 2,143
Annual Depreciation Rate	2.60%	2.70%
Estimated useful life (Avg. Years)	38 years	37 years
Bridges, Trestles, and Culverts
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,688	$ 2,529
Accumulated Depreciation	(380)	(334)
Properties - Net (Note 6)	$ 2,308	$ 2,195
Annual Depreciation Rate	1.70%	1.60%
Estimated useful life (Avg. Years)	60 years	61 years
Signals and Interlockers
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 3,170	$ 3,077
Accumulated Depreciation	(944)	(819)
Properties - Net (Note 6)	$ 2,226	$ 2,258
Annual Depreciation Rate	4.10%	4.00%
Estimated useful life (Avg. Years)	24 years	25 years
Buildings
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,366	$ 1,335
Accumulated Depreciation	(529)	(492)
Properties - Net (Note 6)	$ 837	$ 843
Annual Depreciation Rate	2.50%	2.50%
Estimated useful life (Avg. Years)	40 years	40 years
Other
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 5,146	$ 5,030
Accumulated Depreciation	(2,101)	(1,980)
Properties - Net (Note 6)	$ 3,045	$ 3,050
Annual Depreciation Rate	4.10%	4.20%
Estimated useful life (Avg. Years)	25 years	24 years
Total Equipment
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 10,227	$ 10,708
Accumulated Depreciation	(3,948)	(4,314)
Properties - Net (Note 6)	6,279	6,394
Locomotive
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	5,085	5,320
Accumulated Depreciation	(1,849)	(2,020)
Properties - Net (Note 6)	$ 3,236	$ 3,300
Annual Depreciation Rate	3.60%	3.60%
Estimated useful life (Avg. Years)	27 years	27 years
Freight Cars
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,557	$ 2,964
Accumulated Depreciation	(540)	(880)
Properties - Net (Note 6)	$ 2,017	$ 2,084
Annual Depreciation Rate	2.90%	2.90%
Estimated useful life (Avg. Years)	35 years	35 years
Work Equipment and Other
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 2,585	$ 2,424
Accumulated Depreciation	(1,559)	(1,414)
Properties - Net (Note 6)	$ 1,026	$ 1,010
Annual Depreciation Rate	8.20%	8.20%
Estimated useful life (Avg. Years)	12 years	12 years
Land
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	$ 1,823	$ 1,836
Properties - Net (Note 6)	1,823	1,836
Construction In Progress
Property, Plant and Equipment, Net, by Type [Abstract]
Cost	371	431
Properties - Net (Note 6)	$ 371	$ 431

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Properties - Narrative (Details

Properties - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Properties - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Percentage of labor costs relating to the deconstruction of old track	20.00%
Percentage of labor costs relating to the installation of new track	80.00%
Percentage of assets depreciated under the group-life method	87.00%
Properties	$ 45,530	$ 45,100	[1]
Depreciation	1,383	1,349	[1]	$ 1,331	[1]
Gains on sale of properties	35	151		154
Impairment expense	8	22		$ 24
Total Equipment
Property, Plant and Equipment [Line Items]
Properties	$ 10,227	10,708
Life studies, frequency period	3 years
Total Road
Property, Plant and Equipment [Line Items]
Properties	$ 33,109	$ 32,125
Life studies, frequency period	6 years

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	12 Months Ended
Leases - Narrative (Details) $ in Millions	Dec. 31, 2020USD ($)mi	Dec. 31, 2019USD ($)		Jan. 01, 2019USD ($)
Lessee, Lease, Description [Line Items]
Right-of-use asset	$ 472	$ 532	[1]	$ 534
Right-of-use asset recognized as non-cash asset addition	11	51
Cash paid for amounts included in measurement of operating lease liabilities	$ 59	$ 60
State of Georgia
Lessee, Lease, Description [Line Items]
Term of lease agreement	50 years
Number of miles of right-of-way with integral equipment leased \| mi	137
Percentage of annual increase in operating lease	2.50%
Maximum \| Other parties
Lessee, Lease, Description [Line Items]
Term of lease agreement	50 years

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Leases - Schedule of Informatio

Leases - Schedule of Information About Company's Operating Leases (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Maturity of Lease Liabilities
2021	$ 47
2022	43
2023	36
2024	36
2025	35
Thereafter	1,172
Total undiscounted operating lease payments	1,369
Less: Imputed interest	(869)
Present value of operating lease liabilities	$ 500	$ 550

Leases - Balance Sheet Classifi

Leases - Balance Sheet Classification and Other Information (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Jan. 01, 2019
Balance Sheet Classification
Right-of-use asset	$ 472	$ 532	[1]	$ 534
Current lease liabilities (recorded in other current liabilities)	45	57
Long-term lease liabilities	455	493	[1]
Total operating lease liabilities	$ 500	$ 550
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherCurrentLiabilitiesMember	us-gaap:OtherCurrentLiabilitiesMember
Other Information
Weighted-average remaining lease term for operating leases	35 years	33 years
Weighted-average discount rate for operating leases	5.00%	5.00%

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Leases - Operating Lease Costs

Leases - Operating Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Rent Expense on Operating Leases	$ 82	$ 84
Operating lease, rent expense			$ 66

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Number of Locomotives and Payments under Long-term Maintenance Program (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)locomotive	Dec. 31, 2019USD ($)locomotive	Dec. 31, 2018USD ($)locomotive
Commitments and Contingencies Disclosure [Abstract]
Amounts Paid \| $	$ 158	$ 139	$ 170
Number of Locomotives \| locomotive	1,874	1,897	1,910

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Annual Payments under Long-term Maintenance Program (Details) $ in Millions	Dec. 31, 2020USD ($)
Unrecorded Unconditional Purchase Obligation [Abstract]
2021	$ 234
2022	226
2023	248
2024	284
2025	298
Thereafter	1,985
Total	3,275
Locomotive Maintenance & Rebuild Payments
Unrecorded Unconditional Purchase Obligation [Abstract]
2021	195
2022	204
2023	228
2024	270
2025	284
Thereafter	1,892
Total	3,073
Other Commitments
Unrecorded Unconditional Purchase Obligation [Abstract]
2021	39
2022	22
2023	20
2024	14
2025	14
Thereafter	93
Total	$ 202

Commitments and Contingencies_3

Commitments and Contingencies - Narrative (Details)	1 Months Ended			12 Months Ended
Commitments and Contingencies - Narrative (Details)	Jun. 30, 2018defendant	Mar. 31, 2016partymi	May 31, 2007entityclaim	Dec. 31, 2020USD ($)mi	Dec. 31, 2019USD ($)
Operating Leased Assets [Line Items]
Casualty and catastrophic property deductible				$ 100,000,000	$ 50,000,000
Non-catastrophic property deductible				$ 75,000,000	$ 25,000,000
Fuel Surcharge Antitrust Litigation
Operating Leased Assets [Line Items]
Number of other U.S.-based entities mentioned in class action lawsuit \| entity			3
Number of consolidated class action lawsuits \| claim			1
Environmental Litigation
Operating Leased Assets [Line Items]
Number of miles pertaining to Passaic River tidal reach required to be studied by EPA \| mi				17
Number of miles under study \| mi		8
Number of parties participating in allocation process to assign responsibility for costs under study \| party		80
Number of defendants \| defendant	110
Minimum \| Pending Litigation
Operating Leased Assets [Line Items]
Range of possible loss from legal proceedings				$ 1,000,000
Maximum \| Pending Litigation
Operating Leased Assets [Line Items]
Range of possible loss from legal proceedings				24,000,000
Casualty \| Maximum
Operating Leased Assets [Line Items]
Self-insured retention amount per occurrence				$ 75,000,000

Employee Benefit Plans - Narrat

Employee Benefit Plans - Narrative (Details) - USD ($)	Jan. 01, 2020	Jan. 01, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Employer contributions			$ 0	$ 0	$ 0
Expected contributions in the next fiscal year			$ 0
Percentage within which the planned allocation is managed			5.00%
Investments at fair value			$ 3,000,000,000	2,825,000,000
Growth-Oriented
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of pension plan assets			60.00%
Investments at fair value			$ 1,816,000,000	2,027,000,000
Immunizing
Defined Benefit Plan Disclosure [Line Items]
Target allocation percentage of pension plan assets			40.00%
Investments at fair value			$ 1,184,000,000	798,000,000
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Net actuarial losses (gains)			$ 197,000,000	418,000,000
Decrease in weighted average discount rate			0.70%
Investments at fair value			$ 3,000,000,000	2,825,000,000	2,431,000,000
Pre-tax (loss) gain to be amortized related to post-retirement obligations			(854,000,000)
Expense associated with savings plans			39,000,000	41,000,000	41,000,000
Post-retirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Life insurance and contributions to the medical program for eligible retirees will be eliminated (younger than)		65 years
Life insurance and contributions to the medical program for eligible retirees will be eliminated (65 years or older)	65 years
Decrease in post-retirement benefit liability as result of plan amendments					102,000,000
Net actuarial losses (gains)			(11,000,000)	$ 22,000,000
Decrease in weighted average discount rate				1.11%
Investments at fair value			0	$ 0	0
Pre-tax (loss) gain to be amortized related to post-retirement obligations			78,000,000
Premium expense incurred under the plan			$ 20,000,000	$ 26,000,000	30,000,000
Post-retirement Benefits \| Pension and Other Post-Employment Benefits
Defined Benefit Plan Disclosure [Line Items]
Gain on decrease in post-retirement benefit liability due to plan amendments recognized in other comprehensive income					$ 102,000,000

Employee Benefit Plans - Summar

Employee Benefit Plans - Summary of Participants (Details)	Jan. 01, 2020employee
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Active Employees	3,373
Retirees and Beneficiaries	11,841
Other	3,854
Total	19,068
Post-retirement Medical Plan
Defined Benefit Plan Disclosure [Line Items]
Active Employees	779
Retirees and Beneficiaries	2,282
Other	0
Total	3,061

Employee Benefit Plans - Schedu

Employee Benefit Plans - Schedule of Future Expected Benefit Payments (Details) $ in Millions	Dec. 31, 2020USD ($)
Pension Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	$ 196
2022	188
2023	187
2024	186
2025	185
2026-2030	898
Total	1,840
Post-retirement Benefits
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]
2021	17
2022	10
2023	9
2024	8
2025	8
2026-2030	28
Total	$ 80

Employee Benefit Plans - Sche_2

Employee Benefit Plans - Schedule of Allocation of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 3,000	$ 2,825
Percent of Total Assets	100.00%	100.00%
Growth-Oriented
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,816	$ 2,027
Percent of Total Assets	61.00%	72.00%
Equity
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,324	$ 1,772
Percent of Total Assets	44.00%	63.00%
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 271	$ 229
Percent of Total Assets	9.00%	8.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 221	$ 26
Percent of Total Assets	8.00%	1.00%
Immunizing
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,184	$ 798
Percent of Total Assets	39.00%	28.00%
Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 1,018	$ 595
Percent of Total Assets	34.00%	21.00%
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Amount	$ 166	$ 203
Percent of Total Assets	5.00%	7.00%

Employee Benefit Plans - Sche_3

Employee Benefit Plans - Schedule of Changes in Benefit Obligation and Fair Value of Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Plan Year	$ 2,825,000,000
Non-qualified Employer Contributions	0	$ 0	$ 0
Fair Value of Plan Assets at End of Plan Year	3,000,000,000	2,825,000,000
Capitalized service costs	3,000,000	3,000,000
Pension Benefits
Actuarial Present Value of Benefit Obligation
Accumulated Benefit Obligation				$ 3,134,000,000	$ 2,963,000,000
Projected Benefit Obligation	3,122,000,000	3,122,000,000	2,758,000,000	3,257,000,000	3,122,000,000
Change in Projected Benefit Obligation:
Projected Benefit Obligation at Beginning of Plan Year	3,122,000,000	2,758,000,000
Service Cost	46,000,000	34,000,000
Interest Cost	82,000,000	103,000,000	92,000,000
Plan Participants' Contributions	0	0
Actuarial Loss (Gain)	197,000,000	418,000,000
Benefits Paid	(190,000,000)	(191,000,000)
Benefit Obligation at End of Plan Year	3,257,000,000	3,122,000,000	2,758,000,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Plan Year	2,825,000,000	2,431,000,000
Actual Return on Plan Assets	345,000,000	568,000,000
Plan Participants' Contributions	0	0
Benefits Paid	(190,000,000)	(191,000,000)
Fair Value of Plan Assets at End of Plan Year	3,000,000,000	2,825,000,000	2,431,000,000
Funded Status at End of Plan Year				(257,000,000)	(297,000,000)
Pension Benefits \| Nonqualified Plan
Change in Plan Assets:
Non-qualified Employer Contributions	20,000,000	17,000,000
Post-retirement Benefits
Actuarial Present Value of Benefit Obligation
Projected Benefit Obligation	117,000,000	118,000,000	118,000,000	96,000,000	117,000,000
Change in Projected Benefit Obligation:
Projected Benefit Obligation at Beginning of Plan Year	117,000,000	118,000,000
Service Cost	1,000,000	1,000,000
Interest Cost	5,000,000	2,000,000	7,000,000
Plan Participants' Contributions	6,000,000	7,000,000
Actuarial Loss (Gain)	(11,000,000)	22,000,000
Benefits Paid	(22,000,000)	(33,000,000)
Benefit Obligation at End of Plan Year	96,000,000	117,000,000	118,000,000
Change in Plan Assets:
Fair Value of Plan Assets at Beginning of Plan Year	0	0
Actual Return on Plan Assets	0	0
Plan Participants' Contributions	6,000,000	7,000,000
Benefits Paid	(22,000,000)	(33,000,000)
Fair Value of Plan Assets at End of Plan Year	0	0	$ 0
Funded Status at End of Plan Year				$ (96,000,000)	$ (117,000,000)
Post-retirement Benefits \| Nonqualified Plan
Change in Plan Assets:
Non-qualified Employer Contributions	$ 16,000,000	$ 26,000,000

Employee Benefit Plans - Sche_4

Employee Benefit Plans - Schedule of Amount Recognized in Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Amounts Recorded in Consolidated Balance Sheets [Abstract]
Long-term Assets	$ 29	$ 25
Current Liabilities	(16)	(17)
Long-term Liabilities	(270)	(305)
Net Amount Recognized in Consolidated Balance Sheets	(257)	(297)
Post-retirement Benefits
Amounts Recorded in Consolidated Balance Sheets [Abstract]
Long-term Assets	0	0
Current Liabilities	(17)	(20)
Long-term Liabilities	(79)	(97)
Net Amount Recognized in Consolidated Balance Sheets	$ (96)	$ (117)

Employee Benefit Plans - Benefi

Employee Benefit Plans - Benefit Obligations in Excess of Plan Assets (Details) $ in Millions	Dec. 31, 2020USD ($)
Projected Benefit Obligation
Aggregate fair value of plan assets	$ 2,884
Aggregate benefit obligation	(3,170)
Accumulated Benefit Obligation
Aggregate fair value of plan assets	2,884
Aggregate benefit obligation	$ (264)

Employee Benefit Plans - Sche_5

Employee Benefit Plans - Schedule of Net Benefit Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Components of expense/ (income) related to net benefit expense [Abstract]
Total (Income)/ Expense Included in Other Income - Net	$ (42)	$ (43)	$ (38)
Pension Benefits
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost Included in Labor and Fringe	43	31	32
Interest Cost	82	103	92
Expected Return on Plan Assets	(176)	(171)	(176)
Amortization of Net Loss	54	30	41
Amortization of Prior Service Cost	0	0	0
Total (Income)/ Expense Included in Other Income - Net	(40)	(38)	(43)
Net Periodic Benefit Cost/(Credit)	3	(7)	(11)
Settlement Gain	(1)	0	(1)
Total Periodic Benefit Cost/(Credit)	2	(7)	(12)
Post-retirement Benefits
Components of expense/ (income) related to net benefit expense [Abstract]
Service Cost Included in Labor and Fringe	1	1	2
Interest Cost	5	2	7
Expected Return on Plan Assets	0	0	0
Amortization of Net Loss	1	0	0
Amortization of Prior Service Cost	(7)	(7)	(2)
Total (Income)/ Expense Included in Other Income - Net	(1)	(5)	5
Net Periodic Benefit Cost/(Credit)	0	(4)	7
Settlement Gain	0	0	0
Total Periodic Benefit Cost/(Credit)	$ 0	$ (4)	$ 7

Employee Benefit Plans - Sche_6

Employee Benefit Plans - Schedule of Pre-tax Change in Other Comprehensive Loss (Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Recognized in the Balance Sheet
Losses (Gains)	$ 28	$ 21
Expense (Income) Recognized in the Income Statement
Amortization of Net Loss	54	30	$ 41
Settlement Gain	(1)	0	(1)
Amortization of Prior Service Costs	0	0	0
Post-retirement Benefits
Recognized in the Balance Sheet
Losses (Gains)	(11)	22
Expense (Income) Recognized in the Income Statement
Amortization of Net Loss	1	0	0
Settlement Gain	0	0	0
Amortization of Prior Service Costs	$ (7)	$ (7)	$ (2)

Employee Benefit Plans - Sche_7

Employee Benefit Plans - Schedule of Weighted-Average Assumptions Used (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Benefit Cost for Current Plan Year	6.75%	6.75%
Benefit Cost for Subsequent Plan Year	6.75%	6.75%
Discount Rates:
Service Cost for Plan Year	3.32%	4.40%
Interest Cost for Plan Year	2.69%	3.87%
Benefit Obligation at End of Plan Year	2.43%	3.13%
Salary Scale Inflation	4.60%	4.60%
Cash Balance Plan Interest Credit Rate	3.75%	3.75%
Post-retirement Benefits
Discount Rates:
Service Cost for Plan Year	2.93%	4.14%
Interest Cost for Plan Year	2.43%	3.51%
Benefit Obligation at End of Plan Year	2.07%	2.87%

Debt and Credit Agreements - Sc

Debt and Credit Agreements - Schedule of Long-term Debt Instruments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Finance Leases Average Interest Rate	14.50%
Subtotal Long-term Debt (including current portion)	$ 16,705	$ 16,238
Finance Leases	3	4
Less Debt Due within One Year	(401)	(245)	[1]
Long-term Debt (excluding current portion)	$ 16,304	15,993	[1]
Notes
Debt Instrument [Line Items]
Debt Average Interest Rates	4.00%
Subtotal Long-term Debt (including current portion)	$ 16,542	16,056
Equipment Obligations
Debt Instrument [Line Items]
Debt Average Interest Rates	6.30%
Subtotal Long-term Debt (including current portion)	$ 160	$ 178

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Debt and Credit Agreements - Na

Debt and Credit Agreements - Narrative (Details) - USD ($)	Dec. 01, 2020	Oct. 15, 2019	Dec. 31, 2020	Jul. 09, 2020	Apr. 29, 2020	Mar. 31, 2020	Mar. 30, 2020	Sep. 12, 2019	Feb. 28, 2019	Sep. 14, 2018
Interest Rate Swap \| Cash Flow Hedging \| Designated as Hedging Instrument
Debt Instrument [Line Items]
Derivative notional value			$ 80,000,000	$ 500,000,000	$ 250,000,000
Unrealized gains, recorded net of tax, in other comprehensive income related to hedge			62,000,000
Commercial Paper
Debt Instrument [Line Items]
Line of credit facility capacity										$ 1,000,000,000
Line of credit amount outstanding			0
2.50% Notes Due 2051
Debt Instrument [Line Items]
Debt issued	$ 500,000,000
Interest rate	2.50%
3.70% Notes Due November 1, 2023
Debt Instrument [Line Items]
Interest rate	3.70%
Outstanding debt redeemed	$ 500,000,000
3.8% Notes Due 2050
Debt Instrument [Line Items]
Debt issued							$ 500,000,000
Interest rate							3.80%
2.40% Notes due 2030
Debt Instrument [Line Items]
Debt issued								$ 400,000,000
Interest rate								2.40%
3.35% Notes due 2049
Debt Instrument [Line Items]
Debt issued								$ 600,000,000
Interest rate								3.35%
3.70% Notes due 2020
Debt Instrument [Line Items]
Interest rate		3.70%
Outstanding debt redeemed		$ 500,000,000
4.25% Notes due 2029
Debt Instrument [Line Items]
Debt issued									$ 600,000,000
Interest rate									4.25%
4.50% Notes Due 2049
Debt Instrument [Line Items]
Debt issued									$ 400,000,000
Interest rate									4.50%
3.25% Notes Due 2027
Debt Instrument [Line Items]
Debt issued			$ 850,000,000
Interest rate			3.25%
Unsecured Revolving Credit Facility Expiring March 2024 \| Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility capacity						$ 1,200,000,000
Line of credit facility, amount outstanding			$ 0

Debt and Credit Agreements - _2

Debt and Credit Agreements - Schedule of Long-term Debt Maturities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Maturities of Long-term Debt [Abstract]
2021	$ 401
2022	162
2023	139
2024	551
2025	601
Thereafter	14,851
Subtotal Long-term Debt (including current portion)	$ 16,705	$ 16,238

Revenues - Disaggregated by Lin

Revenues - Disaggregated by Lines of Business (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 10,583	$ 11,937	[1]	$ 12,250	[1]
Total Merchandise
Disaggregation of Revenue [Line Items]
Revenue	7,076	7,589		7,491
Chemicals
Disaggregation of Revenue [Line Items]
Revenue	2,309	2,349		2,344
Agricultural and Food Products
Disaggregation of Revenue [Line Items]
Revenue	1,386	1,410		1,306
Automotive
Disaggregation of Revenue [Line Items]
Revenue	920	1,236		1,267
Forest Products
Disaggregation of Revenue [Line Items]
Revenue	824	862		834
Metals and Equipment
Disaggregation of Revenue [Line Items]
Revenue	675	742		771
Minerals
Disaggregation of Revenue [Line Items]
Revenue	538	559		527
Fertilizers
Disaggregation of Revenue [Line Items]
Revenue	424	431		442
Intermodal
Disaggregation of Revenue [Line Items]
Revenue	1,702	1,760		1,931
Coal
Disaggregation of Revenue [Line Items]
Revenue	1,397	2,070		2,246
Other
Disaggregation of Revenue [Line Items]
Revenue	$ 408	$ 518		$ 582

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Revenues - Narrative (Details)

Revenues - Narrative (Details)	12 Months Ended
Revenues - Narrative (Details)	Dec. 31, 2020
Concentration Risk [Line Items]
Payment period after invoice date	15 days
Expected period to recognized unearned portion of revenue for freight services in transit	The Company expects to recognize the unearned portion of revenue for freight services in transit within one week of the reporting date.
Minimum
Concentration Risk [Line Items]
Average transit time to complete a shipment	2 days
Maximum
Concentration Risk [Line Items]
Average transit time to complete a shipment	7 days

Revenues - Accounts Receivables

Revenues - Accounts Receivables, Net (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable, net	$ 912	$ 986
Freight Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	716	790
Allowance for Credit Losses	(16)	(21)
Total Accounts Receivable, net	700	769
Non-Freight Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables	224	226
Allowance for Credit Losses	(12)	(9)
Total Accounts Receivable, net	$ 212	$ 217

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Income Tax Disclosure [Abstract]
Earnings before income taxes	$ 3,627	$ 4,316	[1]	$ 4,304	[1]
Additional income tax benefit	30	77		62
Unrecognized tax benefits	16	13		12
Amount of unrecognized tax benefits that could favorably impact effective income tax rate	$ 13	$ 10		$ 9

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Income Taxes - Breakdown of Inc

Income Taxes - Breakdown of Income Tax Expense Between Current and Deferred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Current:
Federal	$ 559	$ 608		$ 572
State	123	104		144
Subtotal Current	682	712		716
Deferred:
Federal	149	235		275
State	31	38		4
Subtotal Deferred	180	273		279
Total Income Tax Expense	$ 862	$ 985	[1]	$ 995	[1]

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Income Taxes - Income Tax Expen

Income Taxes - Income Tax Expense Reconciled to Tax Computed at Statutory Rates (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Expense
Federal Income Taxes	$ 762	$ 906		$ 904
State Income Taxes	117	108		112
Other	(17)	(29)		(21)
Total Income Tax Expense	$ 862	$ 985	[1]	$ 995	[1]
Rate
Federal Income Taxes	21.00%	21.00%		21.00%
State Income Taxes	3.20%	2.50%		2.60%
Other	(0.40%)	(0.70%)		(0.50%)
Income Tax Rate	23.80%	22.80%		23.10%

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Income Taxes - Schedule of Sign

Income Taxes - Schedule of Significant Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Assets
Pension Plans	$ 62	$ 71
Other Employee Benefit Plans	96	127
Other	320	426
Total	478	624
Liabilities
Accelerated Depreciation	7,195	7,020
Other	451	565
Total	7,646	7,585
Net Deferred Income Tax Liabilities	$ 7,168	$ 6,961	[1]

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Jul. 09, 2020	Apr. 29, 2020
Interest Rate Swap \| Cash Flow Hedging \| Designated as Hedging Instrument
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative notional value	$ 80	$ 500	$ 250
Growth-Oriented
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Target allocation percentage of pension plan assets	60.00%
Immunizing
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Target allocation percentage of pension plan assets	40.00%
Partnerships
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net asset value, redemption restriction period	15 days
Commingled and Common Collective Trust Funds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net asset value, redemption restriction period	15 days

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Investment Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	$ 101	$ 1,084
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at amortized cost	89	1,076
Level 2 \| Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	101	1,084
Level 2 \| Fair Value \| Corporate Bonds
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	68	59
Level 2 \| Fair Value \| Government Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	33	36
Level 2 \| Fair Value \| Commercial Paper and Certificates of Deposit
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total investments at fair value	$ 0	$ 989

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Investment Maturities (Details) - Fair Value - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Less than 1 year	$ 2	$ 996
1 - 5 years	22	10
5 - 10 years	23	25
Greater than 10 years	54	53
Total investments at fair value	$ 101	$ 1,084

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Fair Value and Carrying Value of Long-term Debt (Details) - Level 2 - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt (Including Current Maturities)	$ 21,076	$ 18,503
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt (Including Current Maturities)	$ 16,705	$ 16,238

Fair Value Measurements - Sch_4

Fair Value Measurements - Schedule of Pension Plan Assets at Fair Value by Level (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	$ 3,000	$ 2,825
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	3,000	2,825	$ 2,431
Pension Plans \| Total
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	2,020	1,952
Pension Plans \| Total \| Common Stock
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	337	823
Pension Plans \| Total \| Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	21	78
Pension Plans \| Total \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	387	229
Pension Plans \| Total \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	1,026	588
Pension Plans \| Total \| Government securities
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	164	217
Pension Plans \| Total \| Asset-backed securities, derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	85	17
Pension Plans \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	745	1,130
Pension Plans \| Level 1 \| Common Stock
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	337	823
Pension Plans \| Level 1 \| Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	21	78
Pension Plans \| Level 1 \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	387	229
Pension Plans \| Level 1 \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 1 \| Government securities
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 1 \| Asset-backed securities, derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	1,275	822
Pension Plans \| Level 2 \| Common Stock
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 2 \| Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 2 \| Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	0	0
Pension Plans \| Level 2 \| Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	1,026	588
Pension Plans \| Level 2 \| Government securities
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	164	217
Pension Plans \| Level 2 \| Asset-backed securities, derivatives and other
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	85	17
Pension Plans \| Investments measured at net asset value
Defined Benefit Plan Disclosure [Line Items]
Investments at fair value	$ 980	$ 873

Other Income - Net (Details)

Other Income - Net (Details) - USD ($) $ in Millions	12 Months Ended
Other Income - Net (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Other Income and Expenses [Abstract]
Net Periodic Pension and Post-retirement Benefit Credit	$ 42	$ 43		$ 38
Interest Income	17	48		32
Debt Repurchase Expense	(48)	(10)		0
Miscellaneous Income	8	7		4
Total Other Income - Net	$ 19	$ 88	[1]	$ 74	[1]

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Investment in Affiliates and _3

Investment in Affiliates and Related-Party Transactions - Equity-method Investments in Affiliates (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019		Dec. 31, 2018
Related Party Transaction [Line Items]
Total	$ 1,985	$ 1,879	[1]
Corporate Joint Venture \| Conrail
Related Party Transaction [Line Items]
Total		1,025		$ 982
Affiliated Entity
Related Party Transaction [Line Items]
Total		1,985		1,879
Affiliated Entity \| TTX
Related Party Transaction [Line Items]
Total		796		743
Affiliated Entity \| Other
Related Party Transaction [Line Items]
Total		$ 164		$ 154

[1]	Certain prior year data has been reclassified to conform to the current presentation.

Investment in Affiliates and _4

Investment in Affiliates and Related-Party Transactions - Narrative (Details) shares in Millions, $ in Millions	Oct. 17, 2019USD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2020USD ($)shares	Dec. 31, 2019USD ($)shares	Dec. 31, 2018USD ($)shares	Dec. 25, 2015note
Related Party Transaction [Line Items]
Number of shares repurchased (in shares) \| shares			13	48	72
Amount of shares repurchased			$ 867	$ 3,373	$ 4,671
January 2019 program
Related Party Transaction [Line Items]
Number of shares repurchased (in shares) \| shares		1.1
Conrail
Related Party Transaction [Line Items]
Payable balance		$ 217	$ 217
Corporate Joint Venture \| Conrail
Related Party Transaction [Line Items]
Ownership percentage		42.00%	42.00%
Voting interest percentage		50.00%	50.00%
Difference between carrying amount and underlying equity		$ 335	$ 335
Promissory notes executed \| note						2
Interest expense			6	$ 6	$ 6
Corporate Joint Venture \| Conrail \| Long-term Debt \| 2.89% Promissory Note Due October 2044
Related Party Transaction [Line Items]
Previous notes converted in non-cash transaction			$ 224
Note interest rate			2.89%
Corporate Joint Venture \| Conrail \| Long-term Debt \| 1.31% Promissory Note Due December 2050
Related Party Transaction [Line Items]
Note interest rate			1.31%
New notes issued in non-cash transaction			$ 441
Affiliated Entity \| TTX
Related Party Transaction [Line Items]
Ownership percentage		20.00%	20.00%
Affiliated Entity \| MR Argent Advisor LLC \| January 2019 program
Related Party Transaction [Line Items]
Number of shares repurchased (in shares) \| shares	4.7
Amount of shares repurchased	$ 319

Investment in Affiliates and _5

Investment in Affiliates and Related-Party Transactions - Schedule of Future Payments Due under Operating Leases (Details) $ in Millions	Dec. 31, 2020USD ($)
Related Party Transaction [Line Items]
2021	$ 47
2022	43
2023	36
2024	36
2025	35
Thereafter	1,172
Total	1,369
Corporate Joint Venture \| Conrail
Related Party Transaction [Line Items]
2021	30
2022	30
2023	30
2024	22
2025	0
Thereafter	0
Total	$ 112

Investment in Affiliates and _6

Investment in Affiliates and Related-Party Transactions - Schedule of Related Party in the Consolidated Income Statement Components (Details) - Materials, Supplies and Other - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Corporate Joint Venture \| Conrail
Related Party Amounts Consolidated Income Statements [Abstract]
Rents, fees and services	$ 126	$ 119	$ 117
Purchase price amortization and other	4	4	4
Equity earnings in affiliates	(49)	(42)	(43)
Total expense	81	81	78
Affiliated Entity \| TTX
Related Party Amounts Consolidated Income Statements [Abstract]
Car hire rents	219	223	223
Equity earnings in affiliates	(51)	(56)	(60)
Total expense	$ 168	$ 167	$ 163

Investment in Affiliates and _7

Investment in Affiliates and Related-Party Transactions - Schedule of Related Party Consolidated Balance Sheet Components (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Corporate Joint Venture \| Conrail \| Accounts Payable
Related Party Transaction [Line Items]
Payable to Affiliates	$ 50	$ 213
Corporate Joint Venture \| Conrail \| Long-term Debt \| 1.31% CSX Promissory Note due December 2050
Related Party Transaction [Line Items]
Promissory note interest rate	1.31%
Promissory notes payable to Conrail subsidiary	$ 73
Corporate Joint Venture \| Conrail \| Long-term Debt \| 1.31% CSXT Promissory Note due December 2050
Related Party Transaction [Line Items]
Promissory note interest rate	1.31%
Promissory notes payable to Conrail subsidiary	$ 368
Corporate Joint Venture \| Conrail \| Long-term Debt \| 2.89% CSX Promissory Note due October 2044
Related Party Transaction [Line Items]
Promissory note interest rate		2.89%
Promissory notes payable to Conrail subsidiary		$ 73
Corporate Joint Venture \| Conrail \| Long-term Debt \| 2.89% CSXT Promissory Note due October 2044
Related Party Transaction [Line Items]
Promissory note interest rate		2.89%
Promissory notes payable to Conrail subsidiary		$ 151
Affiliated Entity \| TTX \| Accounts Payable
Related Party Transaction [Line Items]
Payable to Affiliates	$ 40	$ 34

Other Comprehensive Income (Los

Other Comprehensive Income (Loss) - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Equity [Abstract]
Comprehensive earnings	$ 2,842	$ 3,317	$ 3,134

Other Comprehensive Income _ _3

Other Comprehensive Income / (Loss) - Changes in AOCI Balance by Components (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Comprehensive Income (Loss):
Effects				$ (107)
(Loss) Income Before Reclassifications		$ 53	$ (48)	(119)
Amounts Reclassified to Net Earnings		52	31	32
Tax Benefit (Expense)		(28)	3	19
Total Other Comprehensive Income (Loss) (Note 16)		77	(14)	(175)
Pension and Other Post-Employment Benefits
Other Comprehensive Income (Loss):
Beginning Balance		(619)	(604)	(440)
Effects				(108)
(Loss) Income Before Reclassifications		(17)	(43)	(111)
Amounts Reclassified to Net Earnings		47	23	38
Tax Benefit (Expense)		(9)	5	17
Total Other Comprehensive Income (Loss) (Note 16)		21	(15)	(164)
Ending Balance		(598)	(619)	(604)
Interest Rate Derivatives
Other Comprehensive Income (Loss):
Beginning Balance		0	0	0
Effects				0
(Loss) Income Before Reclassifications		80	0	0
Amounts Reclassified to Net Earnings		0	0	0
Tax Benefit (Expense)		(18)	0	0
Total Other Comprehensive Income (Loss) (Note 16)		62	0	0
Ending Balance		62	0	0
Other
Other Comprehensive Income (Loss):
Beginning Balance		(56)	(57)	(46)
Effects				1
(Loss) Income Before Reclassifications		(10)	(5)	(8)
Amounts Reclassified to Net Earnings		5	8	(6)
Tax Benefit (Expense)		(1)	(2)	2
Total Other Comprehensive Income (Loss) (Note 16)		(6)	1	(11)
Ending Balance		(62)	(56)	(57)
Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss):
Beginning Balance		(675)	(661)	(486)
Total Other Comprehensive Income (Loss) (Note 16)	[1]	77	(14)	(175)
Ending Balance		$ (598)	$ (675)	$ (661)

[1]	Accumulated Other Comprehensive Loss year-end balances shown above are net of tax. The associated taxes were $156 million, $184 million and $180 million for 2020, 2019 and 2018, respectively. For additional information see Note 16, Other Comprehensive Income.