Related Party Transactions (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Related Party Transaction [Line Items]
Cash distributions	$ 1,100	$ 1,100	$ 1,000	$ 1,100	$ 2,100
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments Related to TTX	$ 825			$ 825		$ 807
TTX Company
Related Party Transaction [Line Items]
Ownership Percentage in TTX Company	17.40%			17.40%
TTX Company
Related Party Transaction [Line Items]
Car Hire Expenditures with TTX	$ 96	$ 108		$ 185	205
Parent Company
Related Party Transaction [Line Items]
Cash distributions				1,100	2,100
Tax payments to Berkshire				664	747
Tax refunds from Berkshire				0	$ 1
Tax Receivable, Berkshire	$ 37			$ 37
Tax Payable, Berkshire						$ 112