INCOME TAXES - Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Loyalty program	$ 611	$ 577
Employee benefits	208	240
Net operating losses	501	320
Operating lease liabilities	327	345
Leasehold maintenance	16	31
Other - assets	173	217
Deferred tax assets	1,836	1,730
Excess of book basis over tax basis on fixed assets	(2,209)	(2,017)
Intangibles - net	(190)	(208)
Operating lease assets	(306)	(320)
Other - liabilities	(89)	(79)
Deferred tax liabilities	2,794	2,624
Valuation allowance	(46)	(40)
Net deferred tax liabilities	$ (1,004)	$ (934)