SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Revenue and Direct Cost Information Relating to Company's Oil and Gas Exploration and Production 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]
Asset retirement obligation accretion	$ 109	$ 107	$ 108
Lease operating expenses	1,127	1,447	1,439
Oil and Gas, Exploration and Production
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	4,037	6,315	7,348
Depreciation, depletion, and amortization	1,643	2,512	2,265
Asset retirement obligation accretion	105	105	107
Lease operating expenses	1,129	1,449	1,439
Gathering, processing, and transmission	379	384	371
Exploration expenses	274	805	503
Impairments related to oil and gas properties	4,319	1,633	338
Production taxes	106	191	203
Income tax	(823)	175	848
Operating costs	7,132	7,254	6,074
Results of operations	(3,095)	(939)	1,274
Oil and Gas, Exploration and Production | United States
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	1,764	2,763	3,279
Depreciation, depletion, and amortization	726	1,508	1,206
Asset retirement obligation accretion	32	29	32
Lease operating expenses	400	645	670
Gathering, processing, and transmission	291	299	282
Exploration expenses	168	688	219
Impairments related to oil and gas properties	3,938	1,633	265
Production taxes	106	191	203
Income tax	(818)	(468)	87
Operating costs	4,843	4,525	2,964
Results of operations	(3,079)	(1,762)	315
Oil and Gas, Exploration and Production | Egypt
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	1,390	2,276	2,748
Depreciation, depletion, and amortization	540	641	688
Asset retirement obligation accretion	0	0	0
Lease operating expenses	424	484	428
Gathering, processing, and transmission	38	40	47
Exploration expenses	63	100	88
Impairments related to oil and gas properties	374	0	63
Production taxes	0	0	0
Income tax	(22)	455	645
Operating costs	1,417	1,720	1,959
Results of operations	(27)	556	789
Oil and Gas, Exploration and Production | North Sea
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	883	1,276	1,321
Depreciation, depletion, and amortization	377	363	371
Asset retirement obligation accretion	73	76	75
Lease operating expenses	305	320	341
Gathering, processing, and transmission	50	45	42
Exploration expenses	28	2	192
Impairments related to oil and gas properties	7	0	10
Production taxes	0	0	0
Income tax	17	188	116
Operating costs	857	994	1,147
Results of operations	26	282	174
Oil and Gas, Exploration and Production | Other International
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	0	0	0
Depreciation, depletion, and amortization	0	0	0
Asset retirement obligation accretion	0	0	0
Lease operating expenses	0	0	0
Gathering, processing, and transmission	0	0	0
Exploration expenses	15	15	4
Impairments related to oil and gas properties	0	0	0
Production taxes	0	0	0
Income tax	0	0	0
Operating costs	15	15	4
Results of operations	$ (15)	$ (15)	$ (4)