Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (11)	$ (37)	$ (102)
Other comprehensive loss
Unrealized gains (losses) and amortization from cash flow hedges net of adjustment for de-designation of fuel hedges, net of deferred tax benefit/(expense)	(1)	4	1
Other comprehensive income (loss)	(1)	4	1
Comprehensive income (loss)	$ (12)	$ (33)	$ (101)