Nature of Operations and Significant Accounting Policies	9 Months Ended
	Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Significant Accounting Policies	Nature of Operations and Significant Accounting Policies Background 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'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. The Company's intermodal business links customers to railroads via trucks and terminals. 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 Quality Carriers, Inc. ("Quality Carriers"), 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. Effective July 1, 2021, CSX acquired Quality Carriers, the largest provider of bulk liquid chemicals truck transportation in North America, from Quality Distribution, Inc. For further details, refer to Note 12, Business Combinations. CSX Intermodal Terminals owns and operates a system of intermodal terminals, predominantly in the eastern United States and also performs 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 includes shipments of plastics and ethanol. CSX Technology and other subsidiaries provide support services for the Company. Sale of Property Rights to the Commonwealth of Virginia On March 26, 2021, the Company entered into a comprehensive agreement to sell certain property rights in three CSX-owned line segments to the Commonwealth of Virginia (“Commonwealth”) over three phases for a total of $525 million. In April 2021, in the first phase of the transaction, the Company closed on the conveyance of a permanent land easement for passenger rail operations, resulting in a $349 million gain recognized in gains on property dispositions on the consolidated income statement. Upon closing of the first phase, cash proceeds of $200 million were received and a receivable was recorded in the amount of $168 million. The Company expects to collect proceeds of $200 million in fourth quarter 2021, partly attributable to the first phase with the remainder towards the next phase. Additional future proceeds and related gains attributable to this conveyance are subject to state funding. The Company anticipates closing on the remaining conveyances by the end of 2022, which will result in future cash proceeds and gains. The timing of future gain recognition is dependent upon the timing of future conveyances as well as collectability. As of September 30, 2021, the carrying values of the remaining assets subject to this transaction were not material. 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 consolidated financial statements and accompanying notes. Where applicable, prior year information has been reclassified to conform to the current presentation. Pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”), certain information and disclosures normally included in the notes to the annual financial statements prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) have been omitted from these interim financial statements. CSX suggests that these financial statements be read in conjunction with the audited financial statements and the notes included in CSX's most recent annual report on Form 10-K and any subsequently filed current reports on Form 8-K. Common Stock Split On June 4, 2021, CSX announced a three-for-one split of the Company’s common stock in the form of a stock dividend. Each shareholder of record on June 18, 2021, received two additional shares of common stock for each share held as of this record date. The new shares were distributed after close of trading on June 28, 2021. All prior period share and per share amounts, common stock, other capital, and retained earnings presented herein have been retroactively adjusted to reflect the impact of the stock split. Proportional adjustments were also made to outstanding awards under the Company's stock-based compensation plans. Other Capital As a result of the stock split during second quarter 2021, CSX's common stock balance was increased and its other capital balance was reduced commensurately. Because this adjustment brought the other capital balance below zero, $1.0 billion was reclassified from retained earnings to other capital to bring the other capital balance to zero as of June 30, 2021. Prior period amounts have also been retroactively adjusted as needed to bring the other capital balance to zero. Fiscal Year The Company's fiscal periods are based upon the calendar year. Except as otherwise specified, references to “third quarter(s)” or “nine months” indicate CSX's fiscal periods ending September 30, 2021 and September 30, 2020, and references to "year-end" indicate the fiscal year ended December 31, 2020. New Accounting Pronouncements In March 2020, the FASB issued ASU Facilitation of the Effects of Reference Rate Reform on Financial Reporting. As the London Interbank Offered Rate ("LIBOR") will no longer be available beginning July 2023, this standard update provides practical expedients for contract modifications made as part of the transition from LIBOR to alternative reference rates. CSX's revolving line of credit currently uses LIBOR as a reference rate. This standard update can be adopted prospectively through December 31, 2022. The Company continues to evaluate the impact of this standard update, but does not anticipate that adoption will have a material impact on the Company's results of operations or financial position.