GOODWILL AND INTANGIBLE ASSETS - Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ 74	$ 16
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Gross Carrying Value	889	889
Accumulated Amortization	74	16
Hawaiian Trademark
Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Value	390	390
Slots
Indefinite-Lived Intangible Assets [Line Items]
Gross Carrying Value	92	92
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	285	285
Accumulated Amortization	21	5
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	21	5
Co-brand Partnerships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Value	122	122
Accumulated Amortization	53	11
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Accumulated Amortization	$ 53	$ 11