Supplemental Financial Information - Accounts Payable (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts payable trade	$ 281	$ 265
Salaries, withholdings and payroll taxes	446	400
Ticket taxes and fees	443	302
Aircraft maintenance payable	151	140
Fuel payable	144	161
Dividends payable	0	107
Accrued third party services	229	269
Other payable	255	218
Accounts payable	$ 1,949	$ 1,862