Revenue - Air Traffic Liability - Loyalty Program Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Change in Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 5,190	$ 4,884	$ 5,189	$ 4,789
Amounts deferred associated with points awarded	903	842	1,750	1,579
Ending balance	5,079	4,884	5,079	4,884
Passenger Customer
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	(989)	(821)	(1,814)	(1,445)
Other
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	$ (25)	$ (21)	$ (46)	$ (39)