Revenue - Air Traffic Liability - Loyalty Program Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Change in Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 4,987	$ 5,190	$ 4,916	$ 5,189
Amounts deferred associated with points awarded	901	903	1,794	1,750
Ending balance	4,962	5,079	4,962	5,079
Passenger Customer
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	(895)	(989)	(1,694)	(1,814)
Other
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	$ (31)	$ (25)	$ (54)	$ (46)