Revenue - Roll Forward of Frequent Flyer Deferred Revenue (Details) - Frequent Flyer - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Frequent Flyer Deferred Revenue [Roll Forward]
Total Frequent flyer deferred revenue - beginning balance	$ 6,495	$ 6,185	$ 6,282	$ 5,975
Total miles awarded	705	439	1,848	1,071
Travel miles redeemed	(601)	(391)	(1,489)	(781)
Non-travel miles redeemed	(21)	(16)	(63)	(48)
Total Frequent flyer deferred revenue - ending balance	$ 6,578	$ 6,217	$ 6,578	$ 6,217