FAIR VALUE MEASUREMENTS- Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Short-term investments	$ 3,268	$ 3,386
Short-term investments expected to mature in one year or less	2,800
Fuel hedge contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain (loss) recognized on derivatives	(394)	$ (146)	$ 85
Unrealized loss on swap	365
Derivative, Gain on Derivative	$ 29