Revenue - Air Traffic Liability Breakout (Details) - USD ($) $ in Millions	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Air traffic liability - passenger travel and ancillary passenger services	$ 3,634		$ 2,936
Air traffic liability - loyalty program	4,884	$ 4,884	4,789	$ 4,719	$ 4,623	$ 4,447
Total Air traffic liability	$ 8,518		$ 7,725	$ 8,679		$ 7,133