SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Costs Incurred in Oil and Gas Property Acquisitions, Exploration and Development Activities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Proved	$ 7	$ 8	$ 6
Unproved	4	57	127
Exploration	328	468	940
Development	872	1,996	2,381
Costs incurred	1,211	2,529	3,454
Capitalized interest	3	32	36
Asset retirement costs	38	(97)	31
United States
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Proved	0	3	0
Unproved	4	47	111
Exploration	8	162	640
Development	332	1,500	1,791
Costs incurred	344	1,712	2,542
Capitalized interest	0	23	23
Asset retirement costs	9	14	93
Egypt
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Proved	7	5	6
Unproved	0	10	16
Exploration	102	139	175
Development	378	374	457
Costs incurred	487	528	654
Capitalized interest	0	0	0
Asset retirement costs	0	0	0
North Sea
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Proved	0	0	0
Unproved	0	0	0
Exploration	68	62	113
Development	162	119	133
Costs incurred	230	181	246
Capitalized interest	0	5	11
Asset retirement costs	29	(111)	(62)
Other International
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Proved	0	0	0
Unproved	0	0	0
Exploration	150	105	12
Development	0	3	0
Costs incurred	150	108	12
Capitalized interest	3	4	2
Asset retirement costs	$ 0	$ 0	$ 0