Nature of Operations and Significant Accounting Policies	12 Months Ended
Dec. 31, 2021
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 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 17, Business Combinations. 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. NOTE 1. Nature of Operations and Significant Accounting Policies, continued Lines of Business During 2021, the Company's services generated $12.5 billion of revenue and served four primary lines of business: merchandise, intermodal, coal and trucking. •The merchandise business shipped 2.6 million carloads (41% of volume) and generated 60% of revenue in 2021. The Company’s merchandise business is comprised of shipments in the following diverse markets: chemicals, agricultural and food products, minerals, automotive, forest products, metals and equipment, and fertilizers. •The intermodal business shipped 3.0 million units (48% of volume) and generated 16% of revenue in 2021. 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 706 thousand carloads (11% of volume) and generated 14% of revenue in 2021. 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 of export coal and the majority of the domestic coal that the Company transports is used for generating electricity or industrial purposes. •The trucking business generated 3% of revenue in 2021. Trucking revenue includes revenue from the operations of Quality Carriers, which was acquired by CSX effective July 1, 2021. Other revenue accounted for 7% of the Company’s total revenue in 2021. This category includes revenue from regional subsidiary railroads and incidental charges, including intermodal storage and equipment usage, demurrage and switching. Revenue from regional subsidiary railroads includes shipments by railroads that the Company does not directly operate. Intermodal storage represents charges for customer storage of containers at an intermodal terminal, ramp facility or offsite location beyond a specified period of time. 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. Employees The Company's number of employees was more than 20,900 as of December 2021, which includes approximately 16,500 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, 2021 and December 31, 2020, and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2021, 2020 and 2019. 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. 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. 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 and environmental reserves (see Note 5, Casualty, Environmental and Other Reserves); •pension and post-retirement medical plan accounting (see Note 9, Employee Benefit Plans); •depreciation policies for assets under the group-life method (see Note 6, Properties); and •goodwill and other intangible assets (see Note 17, Business Combinations and Note 18, Goodwill and Other Intangibles - Net). 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, 2021, December 31, 2020, and December 31, 2019. 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. NOTE 1. Nature of Operations and Significant Accounting Policies, continued 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 March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update 2020-04, 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. In November 2021, the FASB issued ASU 2021-10, Disclosure by Business Entities about Government Assistance. This standard update requires annual disclosure of the nature of any government assistance received, accounting policies related to such assistance and the effect of that assistance on the entity’s financial statements. The Company is required to adopt this guidance effective January 2022, though early adoption is permitted. The Company is currently evaluating the impact of these amendments on its disclosures, but this standard update will not impact the Company's results of operations or financial position.

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. 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.

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 17, Business Combinations. 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.

•The merchandise business shipped 2.6 million carloads (41% of volume) and generated 60% of revenue in 2021. The Company’s merchandise business is comprised of shipments in the following diverse markets: chemicals, agricultural and food products, minerals, automotive, forest products, metals and equipment, and fertilizers.

•The intermodal business shipped 3.0 million units (48% of volume) and generated 16% of revenue in 2021. 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 706 thousand carloads (11% of volume) and generated 14% of revenue in 2021. 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 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 7% of the Company’s total revenue in 2021. This category includes revenue from regional subsidiary railroads and incidental charges, including intermodal storage and equipment usage, demurrage and switching. Revenue from regional subsidiary railroads includes shipments by railroads that the Company does not directly operate. Intermodal storage represents charges for customer storage of containers at an intermodal terminal, ramp facility or offsite location beyond a specified period of time. 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.

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, 2021 and December 31, 2020, and the consolidated statements of income, comprehensive income, cash flows and changes in shareholders’ equity for fiscal years 2021, 2020 and 2019. 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.

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.

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:

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.

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 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 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.

In March 2020, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update 2020-04, 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.

In November 2021, the FASB issued ASU 2021-10, Disclosure by Business Entities about Government Assistance. This standard update requires annual disclosure of the nature of any government assistance received, accounting policies related to such assistance and the effect of that assistance on the entity’s financial statements. The Company is required to adopt this guidance effective January 2022, though early adoption is permitted. The Company is currently evaluating the impact of these amendments on its disclosures, but this standard update will not impact the Company's results of operations or financial position.