REVENUE - Air Traffic Liability - Loyalty Program Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Air traffic liability
Beginning balance	$ 4,789	$ 4,447
Amounts deferred associated with points awarded	3,506	2,523
Ending balance	5,189	4,789
Passenger Customer
Air traffic liability
Revenue recognized from points redeemed	(3,028)	(2,136)
Other
Air traffic liability
Revenue recognized from points redeemed	$ (78)	$ (45)