Business Combinations - Allocation of Total Consideration to Fair Value of Assets and Liabilities of Quality Carriers (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Jun. 01, 2022	Dec. 31, 2021	Jul. 01, 2021
Assets Acquired:
Goodwill	$ 325	$ 319		$ 276
Pan-Am
Assets Acquired:
Accounts Receivable, net			$ 46
Properties and Equipment, net			600
Goodwill			17
Intangible Assets			90
Other Assets			11
Total Assets Acquired			764
Liabilities Assumed:
Accounts Payable and Accrued Liabilities			32
Deferred Tax Liabilities			75
Other Long-term Liabilities			57
Total Liabilities Assumed			164
Fair Value of Assets Acquired, Net of Liabilities Assumed:			$ 600
Quality Carriers
Assets Acquired:
Cash and Cash Equivalents					$ 3
Accounts Receivable, net					113
Properties and Equipment, net					225
Goodwill					213
Intangible Assets					180
Other Assets					9
Total Assets Acquired					743
Liabilities Assumed:
Accounts Payable and Accrued Liabilities					48
Finance Lease Obligations and Notes Payable					68
Casualty, Environmental and Other Reserves					62
Other Long-term Liabilities					21
Total Liabilities Assumed					199
Fair Value of Assets Acquired, Net of Liabilities Assumed:					$ 544