REVENUE - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jul. 28, 2022	Dec. 31, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Modification of contract				$ 1,900
Residual travel funds (as a percent)	9.00%	16.00%			2.00%
Loyalty points, redemption period (in years)	2 years
Total operating revenues	$ 23,814	$ 15,790	$ 9,048
Other Revenue
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total operating revenues	$ 2,100	$ 1,400	$ 1,100