BUSINESS SEGMENT INFORMATION (Details) $ in Millions	3 Months Ended			6 Months Ended
	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) Segment	Jun. 30, 2019 USD ($)
Segment Reporting [Abstract]
Number of reporting segments | Segment				3
Segment Reporting Information [Line Items]
Lease operating expenses	$ 264		$ 389	$ 599	$ 754
Taxes other than income	23		46	56	97
Exploration	72		95	129	164
Depreciation, depletion, and amortization	418		602	984	1,248
Asset retirement obligation accretion	27		26	54	53
Impairments	20	$ 4,500	240	4,492	240
Operating expenses	942		1,489	6,589	2,757
Operating Income (Loss)	(190)		127	(4,493)	537
Other Income (Expense):
Gain on divestitures	0		17	25	20
Derivative instrument losses, net	(175)		(8)	(278)	(38)
Other, net	19		(7)	32	(1)
General and administrative	(94)		(102)	(162)	(225)
Transaction, reorganization, and separation	(10)		(6)	(37)	(10)
Financing costs, net	34		(173)	(69)	(270)
NET INCOME (LOSS) BEFORE INCOME TAXES	(416)		(152)	(4,982)	13
Total assets	12,999		21,806	12,999	21,806
Impairments	20		240	4,492	240
Operating Segments | Egypt
Segment Reporting Information [Line Items]
Lease operating expenses	98		132	210	250
Taxes other than income	0		0	0	0
Exploration	22		30	40	62
Depreciation, depletion, and amortization	158		174	319	361
Asset retirement obligation accretion	0		0	0	0
Impairments	20		0	529	0
Operating expenses	311		346	1,121	695
Operating Income (Loss)	(53)		250	(462)	500
Other Income (Expense):
Total assets	3,098		4,035	3,098	4,035
Impairments	22		2	533	4
Operating Segments | North Sea
Segment Reporting Information [Line Items]
Lease operating expenses	75		92	156	164
Taxes other than income	0		0	0	0
Exploration	15		1	17	2
Depreciation, depletion, and amortization	79		99	188	198
Asset retirement obligation accretion	18		18	36	37
Impairments	0		0	7	0
Operating expenses	198		221	431	424
Operating Income (Loss)	(60)		139	4	274
Other Income (Expense):
Total assets	2,339		2,568	2,339	2,568
Impairments				7
Operating Segments | U.S.
Segment Reporting Information [Line Items]
Lease operating expenses	90		166	233	342
Taxes other than income	20		42	49	91
Exploration	31		59	66	92
Depreciation, depletion, and amortization	178		320	471	673
Asset retirement obligation accretion	8		8	16	15
Impairments	0		240	3,956	240
Operating expenses	443		914	5,067	1,635
Operating Income (Loss)	(88)		(254)	(4,066)	(234)
Other Income (Expense):
Total assets	5,821		12,710	5,821	12,710
Impairments	29		277	4,000	298
Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Lease operating expenses	0		0	0	0
Taxes other than income	3		4	7	6
Exploration	0		0	0	0
Depreciation, depletion, and amortization	3		9	6	16
Asset retirement obligation accretion	1		0	2	1
Impairments	0		0	0	0
Operating expenses	17		27	36	53
Operating Income (Loss)	15		(3)	37	5
Other Income (Expense):
Total assets	1,627		2,434	1,627	2,434
Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	(31)		(24)	(72)	(58)
Lease operating expenses	1		(1)	0	(2)
Taxes other than income	0		0	0	0
Exploration	4		5	6	8
Depreciation, depletion, and amortization	0		0	0	0
Asset retirement obligation accretion	0		0	0	0
Impairments	0		0	0	0
Operating expenses	(27)		(19)	(66)	(50)
Operating Income (Loss)	(4)		(5)	(6)	(8)
Other Income (Expense):
Total assets	114		59	114	59
Intersegment Eliminations & Other | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	(31)		(24)	(72)	(58)
Oil and gas
Segment Reporting Information [Line Items]
Oil and gas production revenues	752		1,616	2,096	3,294
Oil and gas | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	258		596	659	1,195
Oil and gas | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	138		360	435	698
Oil and gas | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	355		660	1,001	1,401
Oil and gas | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	32		24	73	58
Oil and gas | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	(31)		(24)	(72)	(58)
Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	697		1,598	1,933	3,252
Cost of oil and gas purchased	72		76	143	164
Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	258		596	659	1,195
Cost of oil and gas purchased	13		10	23	22
Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	138		360	435	698
Cost of oil and gas purchased	11		11	27	23
Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	301		642	839	1,359
Cost of oil and gas purchased	70		64	145	145
Oil and gas, excluding purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Cost of oil and gas purchased	10		14	20	30
Oil and gas, excluding purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Cost of oil and gas purchased	(32)		(23)	(72)	(56)
Oil and gas, purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	55		18	163	42
Cost of oil and gas purchased	46		15	132	37
Oil and gas, purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Cost of oil and gas purchased	0		0	0	0
Oil and gas, purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Cost of oil and gas purchased	0		0	0	0
Oil and gas, purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	54		18	162	42
Cost of oil and gas purchased	46		15	131	37
Oil and gas, purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	1		0	1	0
Cost of oil and gas purchased	0		0	1	0
Oil and gas, purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Cost of oil and gas purchased	0		0	0	0
Oil
Other Income (Expense):
Revenues from non-customer	(18)		111	27	218
Oil | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	513		1,397	1,545	2,707
Oil | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	187		523	520	1,037
Oil | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	128		337	399	637
Oil | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	198		537	626	1,033
Oil | Oil and gas, excluding purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Oil | Oil and gas, excluding purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Natural Gas
Other Income (Expense):
Revenues from non-customer	0		9	3	21
Natural Gas | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	130		118	253	354
Natural Gas | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	70		70	135	151
Natural Gas | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	7		18	26	50
Natural Gas | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	53		30	92	153
Natural Gas | Oil and gas, excluding purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Natural Gas | Oil and gas, excluding purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Natural Gas liquids
Other Income (Expense):
Revenues from non-customer	0		0	0	1
Natural Gas liquids | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	54		83	135	191
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	1		3	4	7
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	3		5	10	11
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	50		75	121	173
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	0		0	0	0
Natural Gas liquids | Oil and gas, excluding purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	$ 0		$ 0	$ 0	$ 0