BUSINESS SEGMENT INFORMATION (Details)	3 Months Ended				9 Months Ended
	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Segment	Sep. 30, 2019 USD ($)
Segment Reporting [Abstract]
Number of reporting segments | Segment					3
Segment Reporting Information [Line Items]
Lease operating expenses	$ 259,000,000			$ 350,000,000	$ 858,000,000	$ 1,104,000,000
Taxes other than income	34,000,000			44,000,000	90,000,000	141,000,000
Exploration	58,000,000			56,000,000	187,000,000	220,000,000
Depreciation, depletion, and amortization	398,000,000			711,000,000	1,382,000,000	1,959,000,000
Accretion expense	27,000,000			27,000,000	81,000,000	80,000,000
Impairments	0	$ 20,000,000	$ 4,500,000,000	9,000,000	4,492,000,000	249,000,000
Operating expenses	914,000,000			1,286,000,000	7,503,000,000	4,043,000,000
Operating Income (Loss)	206,000,000			182,000,000	(4,287,000,000)	719,000,000
Other Income (Expense):
Derivative instrument gains (losses), net	16,000,000			(2,000,000)	(262,000,000)	(40,000,000)
Gain (loss) on divestitures, net	(1,000,000)			0	24,000,000	20,000,000
Other, net	9,000,000			34,000,000	41,000,000	33,000,000
General and administrative	(52,000,000)			(98,000,000)	(214,000,000)	(323,000,000)
Transaction, reorganization, and separation	(7,000,000)			(7,000,000)	(44,000,000)	(17,000,000)
Financing costs, net	(99,000,000)			(95,000,000)	(168,000,000)	(365,000,000)
NET INCOME (LOSS) BEFORE INCOME TAXES	72,000,000			14,000,000	(4,910,000,000)	27,000,000
Total assets	12,875,000,000			21,405,000,000	12,875,000,000	21,405,000,000
Impairments	0			9,000,000	4,492,000,000	249,000,000
Operating Segments | Egypt
Segment Reporting Information [Line Items]
Lease operating expenses	102,000,000			115,000,000	312,000,000	365,000,000
Taxes other than income	0			0	0	0
Exploration	10,000,000			27,000,000	51,000,000	89,000,000
Depreciation, depletion, and amortization	144,000,000			177,000,000	463,000,000	538,000,000
Accretion expense	0			0	0	0
Impairments				0	529,000,000	0
Operating expenses	264,000,000			328,000,000	1,386,000,000	1,023,000,000
Operating Income (Loss)	115,000,000			218,000,000	(348,000,000)	718,000,000
Other Income (Expense):
Total assets	3,052,000,000			3,851,000,000	3,052,000,000	3,851,000,000
Impairments	2,000,000			2,000,000	535,000,000	6,000,000
Operating Segments | North Sea
Segment Reporting Information [Line Items]
Lease operating expenses	79,000,000			76,000,000	234,000,000	240,000,000
Taxes other than income	0			0	0	0
Exploration	10,000,000			0	26,000,000	2,000,000
Depreciation, depletion, and amortization	90,000,000			71,000,000	278,000,000	269,000,000
Accretion expense	18,000,000			19,000,000	54,000,000	56,000,000
Impairments				0	7,000,000	0
Operating expenses	207,000,000			175,000,000	636,000,000	599,000,000
Operating Income (Loss)	(10,000,000)			75,000,000	(4,000,000)	349,000,000
Other Income (Expense):
Total assets	2,238,000,000			2,529,000,000	2,238,000,000	2,529,000,000
Impairments					7,000,000
Operating Segments | U.S.
Segment Reporting Information [Line Items]
Lease operating expenses	79,000,000			159,000,000	313,000,000	501,000,000
Taxes other than income	30,000,000			41,000,000	79,000,000	131,000,000
Exploration	34,000,000			25,000,000	100,000,000	117,000,000
Depreciation, depletion, and amortization	161,000,000			452,000,000	632,000,000	1,125,000,000
Accretion expense	8,000,000			8,000,000	24,000,000	23,000,000
Impairments				0	3,956,000,000	240,000,000
Operating expenses	460,000,000			777,000,000	5,528,000,000	2,411,000,000
Operating Income (Loss)	83,000,000			(105,000,000)	(3,984,000,000)	(338,000,000)
Other Income (Expense):
Total assets	5,708,000,000			12,289,000,000	5,708,000,000	12,289,000,000
Impairments	34,000,000			10,000,000	4,000,000,000.0	308,000,000
Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Lease operating expenses	0			0	0	0
Taxes other than income	4,000,000			3,000,000	11,000,000	10,000,000
Exploration	0			0	0	0
Depreciation, depletion, and amortization	3,000,000			11,000,000	9,000,000	27,000,000
Accretion expense	1,000,000			0	3,000,000	1,000,000
Impairments				9,000,000	0	9,000,000
Operating expenses	18,000,000			36,000,000	54,000,000	90,000,000
Operating Income (Loss)	22,000,000			(2,000,000)	59,000,000	2,000,000
Other Income (Expense):
Total assets	1,741,000,000			2,648,000,000	1,741,000,000	2,648,000,000
Impairments				9,000,000		9,000,000
Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	(39,000,000)			(34,000,000)	(111,000,000)	(92,000,000)
Lease operating expenses	(1,000,000)			0	(1,000,000)	(2,000,000)
Taxes other than income	0			0	0	0
Exploration	4,000,000			4,000,000	10,000,000	12,000,000
Depreciation, depletion, and amortization	0			0	0	0
Accretion expense	0			0	0	0
Impairments				0	0	0
Operating expenses	(35,000,000)			(30,000,000)	(101,000,000)	(80,000,000)
Operating Income (Loss)	(4,000,000)			(4,000,000)	(10,000,000)	(12,000,000)
Other Income (Expense):
Total assets	136,000,000			88,000,000	136,000,000	88,000,000
Intersegment Eliminations & Other | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	(39,000,000)			(34,000,000)	(111,000,000)	(92,000,000)
Oil and gas
Segment Reporting Information [Line Items]
Oil and gas production revenues	1,120,000,000			1,468,000,000	3,216,000,000	4,762,000,000
Oil and gas | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	379,000,000			546,000,000	1,038,000,000	1,741,000,000
Oil and gas | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	197,000,000			250,000,000	632,000,000	948,000,000
Oil and gas | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	543,000,000			672,000,000	1,544,000,000	2,073,000,000
Oil and gas | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	40,000,000			34,000,000	113,000,000	92,000,000
Oil and gas | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues	(39,000,000)			(34,000,000)	(111,000,000)	(92,000,000)
Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	1,046,000,000			1,438,000,000	2,979,000,000	4,690,000,000
Cost of oil and gas purchased	63,000,000			66,000,000	206,000,000	230,000,000
Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	379,000,000			546,000,000	1,038,000,000	1,741,000,000
Cost of oil and gas purchased	8,000,000			9,000,000	31,000,000	31,000,000
Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	197,000,000			250,000,000	632,000,000	948,000,000
Cost of oil and gas purchased	10,000,000			9,000,000	37,000,000	32,000,000
Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	470,000,000			642,000,000	1,309,000,000	2,001,000,000
Cost of oil and gas purchased	74,000,000			69,000,000	219,000,000	214,000,000
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	9,000,000			13,000,000	29,000,000	43,000,000
Oil and gas, excluding purchased | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Cost of oil and gas purchased	(38,000,000)			(34,000,000)	(110,000,000)	(90,000,000)
Oil and gas, purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	74,000,000			30,000,000	237,000,000	72,000,000
Cost of oil and gas purchased	75,000,000			23,000,000	207,000,000	60,000,000
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	73,000,000			30,000,000	235,000,000	72,000,000
Cost of oil and gas purchased	74,000,000			23,000,000	205,000,000	60,000,000
Oil and gas, purchased | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues	1,000,000			0	2,000,000	0
Cost of oil and gas purchased	1,000,000			0	2,000,000	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	38,000,000			98,000,000	65,000,000	316,000,000
Oil | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	785,000,000			1,207,000,000	2,330,000,000	3,914,000,000
Oil | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	303,000,000			472,000,000	823,000,000	1,509,000,000
Oil | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	179,000,000			231,000,000	578,000,000	868,000,000
Oil | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	303,000,000			504,000,000	929,000,000	1,537,000,000
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	6,000,000			9,000,000	9,000,000	30,000,000
Natural Gas | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	164,000,000			136,000,000	417,000,000	490,000,000
Natural Gas | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	74,000,000			72,000,000	209,000,000	223,000,000
Natural Gas | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	13,000,000			14,000,000	39,000,000	64,000,000
Natural Gas | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	77,000,000			50,000,000	169,000,000	203,000,000
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	1,000,000
Natural Gas liquids | Oil and gas, excluding purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues	97,000,000			95,000,000	232,000,000	286,000,000
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues	2,000,000			2,000,000	6,000,000	9,000,000
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues	5,000,000			5,000,000	15,000,000	16,000,000
Natural Gas liquids | Oil and gas, excluding purchased | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues	90,000,000			88,000,000	211,000,000	261,000,000
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