INCOME TAXES - Net Deferred Tax Liability (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
U.S. and state net operating losses	$ 2,108	$ 1,633
Capital losses	626	636
Tax credits and other tax incentives	32	39
Foreign tax credits	2,241	2,241
Accrued expenses and liabilities	97	117
Asset retirement obligation	618	649
Equity investments	0	4
Investment in Altus Midstream LP	107	0
Net interest expense limitation	162	65
Other	88	97
Lease liability	108	0
Total deferred tax assets	6,187	5,481
Valuation allowance	(4,959)	(3,947)	$ (3,816)	$ (5,401)
Net deferred tax assets	1,228	1,534
Deferred tax liabilities:
Deferred income	1	10
Investment in Altus Midstream LP	0	73
Property and equipment	1,432	1,747
Right-of-use asset	106	0
Other	6	4
Total deferred tax liabilities	1,545	1,834
Net deferred income tax liability	$ 317	$ 300