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, 2021	Dec. 31, 2020	Dec. 31, 2019
Corporate Joint Venture \| Conrail
Related Party Amounts Consolidated Income Statements [Abstract]
Rents, fees and services	$ 128	$ 126	$ 119
Purchase price amortization and other	4	4	4
Equity earnings in affiliates	(44)	(49)	(42)
Total expense	88	81	81
Affiliated Entity \| TTX
Related Party Amounts Consolidated Income Statements [Abstract]
Car hire rents	221	219	223
Equity earnings in affiliates	(52)	(51)	(56)
Total expense	$ 169	$ 168	$ 167

Car Hire Rents

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- Definition

The amortization of the fair value write-up of fixed assets when the original purchase price from the acquisition was allocated based on fair value.

+ References

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Related Party Amounts Consolidated Income Statements [Abstract]

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- Definition

Total amount of related party rents, fees and services in the Company's consolidated income statements.

+ References

No definition available.

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- Definition

Amount of income (loss) for proportionate share of equity method investee's income (loss).

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Expenses recognized resulting from transactions (excluding transactions that are eliminated in consolidated or combined financial statements) with related party.

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