Revenue - Air Traffic Liability - Loyalty Program Rollforward (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Change in Contract With Customer, Liability [Roll Forward]
Beginning balance	$ 5,189	$ 4,789
Amounts deferred associated with points awarded	846	736
Ending balance	5,190	4,884
Passenger Customer
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	(825)	(624)
Other
Change in Contract With Customer, Liability [Roll Forward]
Revenue recognized from points redeemed	$ (20)	$ (17)