Intangible Assets, net - Summary of Intangible Assets (Details) - USD ($) $ in Millions	1 Months Ended	8 Months Ended	12 Months Ended
	Sep. 30, 2020	Aug. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets			$ 26	$ 26
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, Accumulated Amortization			(13)	(13)
Total intangible assets, net, Gross Carrying Amount			42	42
Intangible assets, net			29	29
Airport slots
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets			20	20
Trademarks
Indefinite-lived Intangible Assets [Line Items]
Indefinite-lived intangible assets			$ 6	6
Affinity credit card program
Finite-Lived Intangible Assets [Line Items]
Amortization Period	16 years	10 years	16 years
Finite-lived intangible assets, Gross Carrying Amount			$ 16	16
Finite-lived intangible assets, Accumulated Amortization			(13)	(13)
Finite-lived intangible assets, net, total			$ 3	$ 3