FINANCIAL DERIVATIVE INSTRUMENTS - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Future hedging period for jet fuel (in months)		24 months
Current unrealized net loss in OCI	$ 55	$ 55
Interest rate derivatives
Derivative [Line Items]
Collateral deposits	0	$ 0	$ 0
Terminated amount	150
Gain on terminated derivatives	$ 23