GENERAL AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - MAINTENANCE DEPOSITS (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Aircraft Maintenance Deposits	$ 140	$ 175
Lease Return Provision, Current	(186)	(53)
Lease Return Provision, Non-Current	$ (91)	$ (114)