DEBT - Narrative (Details) - USD ($)	1 Months Ended	9 Months Ended
	Nov. 06, 2025	Sep. 30, 2025	Sep. 30, 2024
Debt Instrument [Line Items]
Weighted-average interest rate (in percent)		4.70%
Debt instrument, increase (decrease)		$ 69,000,000
Long-term debt payments		389,000,000	$ 279,000,000
Subsequent Event | Hawaiian Airlines
Debt Instrument [Line Items]
Long-term debt payments	$ 67,000,000
Other Debt Obligations
Debt Instrument [Line Items]
Debt instrument, face amount		452,000,000
Other Debt Obligations | Secured Debt
Debt Instrument [Line Items]
Debt instrument, face amount		383,000,000
Alaskan And Hawaiian Credit Facility | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, borrowing capacity		850,000,000
Outstanding borrowing		0
Alaskan Credit Facility | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, borrowing capacity		106,000,000
Interest rate swap agreements | Cash Flow Hedging | Derivative Instruments Designated as Hedges
Debt Instrument [Line Items]
Notional amount		$ 521,000,000