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, 2019	Dec. 31, 2018	Dec. 31, 2017
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	$ 6,315	$ 7,348	$ 5,887
Asset retirement obligation accretion	107	108	130
Lease operating expenses	1,447	1,439	1,384
Gathering, processing, and transmission	306	348	195
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	6,315	7,348	5,887
Depreciation, depletion, and amortization	2,512	2,265	2,136
Asset retirement obligation accretion	105	107	130
Lease operating expenses	1,449	1,439	1,384
Gathering, processing, and transmission	384	371	194
Exploration expenses	805	503	549
Impairments related to oil and gas properties	1,633	338
Production taxes	191	203	150
Income tax	175	848	601
Operating costs	7,254	6,074	5,144
Results of operations	(939)	1,274	743
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	2,763	3,279	2,271
Depreciation, depletion, and amortization	1,508	1,206	924
Asset retirement obligation accretion	29	32	31
Lease operating expenses	645	670	584
Gathering, processing, and transmission	299	282	86
Exploration expenses	688	219	363
Impairments related to oil and gas properties	1,633	265
Production taxes	191	203	153
Income tax	(468)	87	45
Operating costs	4,525	2,964	2,186
Results of operations	(1,762)	315	85
Oil and Gas, Exploration and Production | Canada
Results of Operations for Oil and Gas Producing Activities, by Geographic Area [Line Items]
Oil and gas production revenues	0	0	231
Depreciation, depletion, and amortization	0	0	72
Asset retirement obligation accretion	0	0	27
Lease operating expenses	0	0	103
Gathering, processing, and transmission	0	0	34
Exploration expenses	0	0	11
Impairments related to oil and gas properties	0	0
Production taxes	0	0	11
Income tax	0	0	(7)
Operating costs	0	0	251
Results of operations	0	0	(20)
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	2,276	2,748	2,307
Depreciation, depletion, and amortization	641	688	707
Asset retirement obligation accretion	0	0	0
Lease operating expenses	484	428	362
Gathering, processing, and transmission	40	47	44
Exploration expenses	100	88	62
Impairments related to oil and gas properties	0	63
Production taxes	0	0	0
Income tax	455	645	509
Operating costs	1,720	1,959	1,684
Results of operations	556	789	623
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	1,276	1,321	1,078
Depreciation, depletion, and amortization	363	371	433
Asset retirement obligation accretion	76	75	72
Lease operating expenses	320	341	335
Gathering, processing, and transmission	45	42	30
Exploration expenses	2	192	86
Impairments related to oil and gas properties	0	10
Production taxes	0	0	(14)
Income tax	188	116	54
Operating costs	994	1,147	996
Results of operations	282	174	82
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	4	27
Impairments related to oil and gas properties	0	0
Production taxes	0	0	0
Income tax	0	0	0
Operating costs	15	4	27
Results of operations	$ (15)	$ (4)	$ (27)