Other Current Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Other Liabilities Disclosure [Abstract]
Passenger and other taxes and fees payable	$ 125	$ 113
Salaries, wages and benefits	107	104
Aircraft maintenance	76	63
Station obligations	69	57
Fuel liabilities	35	34
Leased aircraft return costs	1	84
Other current liabilities	48	63
Total other current liabilities	$ 461	$ 518