ACQUISITION OF HAWAIIAN HOLDINGS, INC. - Pro Forma Impact Of Acquisition (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024
Business Combination, Pro Forma Information [Line Items]
Net loss	$ (73)	$ (172)	$ 166	$ (236)	$ (220)	$ 132	$ (79)	$ (324)
Revenue							10,607	10,245
Net income							$ 188	137
Hawaiian Holdings, Inc.
Business Combination, Pro Forma Information [Line Items]
Revenue	3,766			3,739
Net income	$ 116			$ 234
Hawaiian Holdings, Inc. | Business Combination, Pro Forma Information, Nonrecurring Adjustment, Acquisition-Related Cost
Business Combination, Pro Forma Information [Line Items]
Net loss								$ 381