Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Accounts and wages payable	$ 552	$ 710
Casualty and other claims (Note 17)	182	212
Vacation liability	121	136
Other	105	106
Total	1,016	1,428
Interest payable	141	149
Current operating lease liability (Note 10)	89	97
Other	53	63
Total	302	327
Pension Plan
Related Party Transaction [Line Items]
Pension benefit obligations (Note 12)	19	18
Conrail Inc.
Related Party Transaction [Line Items]
Due to Conrail (Note 6)	$ 56	$ 264

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