Revenue - Air Traffic Liability - Loyalty Program Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Change in Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 4,962	$ 5,079	$ 4,916	$ 5,189
Amounts deferred associated with points awarded	851	859	2,645	2,609
Ending balance	4,886	4,996	4,886	4,996
Passenger Customer
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	(896)	(916)	(2,589)	(2,730)
Other
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	$ (31)	$ (26)	$ (86)	$ (72)