Investment in Affiliates and Related-Party Transactions - Schedule of Related Party in the Consolidated Income Statement Components (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Related Party Amounts Consolidated Income Statements [Abstract]
Total Expense	$ 9,096	$ 8,830	$ 6,928
Corporate Joint Venture \| Conrail
Related Party Amounts Consolidated Income Statements [Abstract]
Rents, Fees and Services	132	130	128
Purchase Price Amortization and Other	4	4	4
Equity Earnings in Affiliates	(54)	(44)	(44)
Total Expense	82	90	88
Related Party \| TTX
Related Party Amounts Consolidated Income Statements [Abstract]
Equity Earnings in Affiliates	(49)	(51)	(52)
Car Hire Rents	249	241	221
Total Expense	$ 200	$ 190	$ 169

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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- Definition

Related Party Amounts Consolidated Income Statements [Abstract]

+ References

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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).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
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-Name Accounting Standards Codification
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 323
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Excludes Selling, General and Administrative Expense.

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