Revenues - Accounts Receivable, Net (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Accounts Receivable - Net	$ 1,400	$ 1,393
Freight Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, gross	1,060	1,047
Allowance for Credit Losses	(18)	(18)
Total Accounts Receivable - Net	1,042	1,029
Non-Freight Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts Receivable, gross	370	378
Allowance for Credit Losses	(12)	(14)
Total Accounts Receivable - Net	$ 358	$ 364