INCOME TAXES - Deferred Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax assets:
Net operating loss carryforwards	$ 1,395	$ 1,301
Capital loss carryforward	50	480
Pension, postretirement and other benefits	1,467	2,089
Investments	1,106	314
Deferred revenue	2,334	2,288
Lease liabilities	2,376	2,452
Other	682	494
Valuation allowance	(1,176)	(833)	$ (460)
Total deferred tax assets	8,234	8,585
Deferred tax liabilities:
Depreciation	5,110	4,463
Operating lease assets	1,624	1,676
Intangible assets	1,121	1,097
Other	78	55
Total deferred tax liabilities	7,933	7,291
Net deferred tax assets	301	1,294
Net state deferred tax assets	$ 325
Net federal deferred tax liabilities		$ 24