BUSINESS SEGMENT INFORMATION - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Segment Reporting Information [Line Items]
Oil and gas production revenues									$ 7,348	$ 5,887	$ 5,367
Operating Expenses:
Lease operating expenses									1,439	1,384	1,494
Gathering, transmission, and processing									348	195	200
Taxes other than income									215	151	126
Exploration									503	549	473
Depreciation, depletion, and amortization									2,405	2,280	2,618
Asset retirement obligation accretion									108	130	156
Impairments	$ 639	$ 49	$ 21	$ 16	$ 32	$ 160	$ 39	$ 23	511	8	1,103
Total operating expenses									5,529	4,697	6,170
Operating Income (Loss)									1,819	1,190	(803)
Other Income (Expense):
Gain on divestitures	13	1	2	7	11	296	(21)	341	23	627	21
Derivative instrument gains (losses), net									(17)	(135)	0
Other									70	44	(34)
General and administrative									(431)	(395)	(410)
Transaction, reorganization, and separation									(28)	(16)	(39)
Financing costs, net									(478)	(397)	(417)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(344)	$ 406	$ 508	$ 388	278	$ 93	$ 9	$ 538	958	918	(1,682)
Net Property and Equipment	18,421				17,759				18,421	17,759	18,867
Total Assets	21,582				21,922				21,582	21,922	22,519
Additions to Net Property and Equipment	3,914				3,302				3,914	3,302	1,681
Revenue from non-customers									652
Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues									2,748	2,307	2,057
Operating Expenses:
Lease operating expenses									428	362	446
Gathering, transmission, and processing									47	44	44
Taxes other than income									0	0	0
Exploration									88	62	48
Depreciation, depletion, and amortization									745	758	778
Asset retirement obligation accretion									0	0	0
Impairments									63	0	1
Total operating expenses									1,371	1,226	1,317
Operating Income (Loss)									1,377	1,081	740
Other Income (Expense):
Net Property and Equipment	2,856				3,099				2,856	3,099	3,362
Total Assets	4,260				4,658				4,260	4,658	4,893
Additions to Net Property and Equipment	594				517				594	517	459
Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues									1,321	1,078	970
Operating Expenses:
Lease operating expenses									341	335	314
Gathering, transmission, and processing									42	30	8
Taxes other than income									0	(14)	(33)
Exploration									192	86	37
Depreciation, depletion, and amortization									375	446	519
Asset retirement obligation accretion									75	72	75
Impairments									10	8	655
Total operating expenses									1,035	963	1,575
Operating Income (Loss)									286	115	(605)
Other Income (Expense):
Net Property and Equipment	2,148				2,553				2,148	2,553	2,834
Total Assets	2,456				2,977				2,456	2,977	3,584
Additions to Net Property and Equipment	223				374				223	374	260
Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues									3,279	2,271	1,997
Operating Expenses:
Lease operating expenses									670	584	553
Gathering, transmission, and processing									282	86	80
Taxes other than income									207	153	139
Exploration									219	363	285
Depreciation, depletion, and amortization									1,266	994	1,138
Asset retirement obligation accretion									32	31	34
Impairments									438	0	80
Total operating expenses									3,114	2,211	2,309
Operating Income (Loss)									165	60	(312)
Other Income (Expense):
Net Property and Equipment	12,145				11,370				12,145	11,370	11,012
Total Assets	12,962				13,522				12,962	13,522	12,247
Additions to Net Property and Equipment	2,544				1,847				2,544	1,847	770
Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Operating Expenses:
Lease operating expenses									0	0	0
Gathering, transmission, and processing									54	16	0
Taxes other than income									8	0	0
Exploration									0	0	0
Depreciation, depletion, and amortization									19	6	0
Asset retirement obligation accretion									1	0	0
Impairments									0	0	0
Total operating expenses									82	22	0
Operating Income (Loss)									(5)	(7)	0
Other Income (Expense):
Net Property and Equipment	1,227				700				1,227	700	156
Total Assets	1,857				706				1,857	706	156
Additions to Net Property and Equipment	545				550				545	550	156
Operating Segments | Canada
Segment Reporting Information [Line Items]
Oil and gas production revenues										231	343
Operating Expenses:
Lease operating expenses										103	181
Gathering, transmission, and processing										34	68
Taxes other than income										12	20
Exploration										11	88
Depreciation, depletion, and amortization										76	183
Asset retirement obligation accretion										27	47
Impairments										0	367
Total operating expenses										263	954
Operating Income (Loss)										(32)	(611)
Other Income (Expense):
Net Property and Equipment					0					0	1,464
Total Assets					0					0	1,591
Additions to Net Property and Equipment					0					0	34
Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues									(77)	(15)	0
Operating Expenses:
Lease operating expenses									0	0	0
Gathering, transmission, and processing									(77)	(15)	0
Taxes other than income									0	0	0
Exploration									4	27	15
Depreciation, depletion, and amortization									0	0	0
Asset retirement obligation accretion									0	0	0
Impairments									0	0	0
Total operating expenses									(73)	12	15
Operating Income (Loss)									(4)	(27)	(15)
Other Income (Expense):
Net Property and Equipment	45				37				45	37	39
Total Assets	47				59				47	59	48
Additions to Net Property and Equipment	$ 8				$ 14				8	14	2
Intersegment Eliminations & Other | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Intersegment Eliminations & Other | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Intersegment Eliminations & Other | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Intersegment Eliminations & Other | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues									77	15	0
Intersegment Eliminations & Other | Canada
Segment Reporting Information [Line Items]
Oil and gas production revenues										0
Oil
Segment Reporting Information [Line Items]
Oil and gas production revenues									5,846	4,598	4,172
Other Income (Expense):
Revenue from non-customers									592
Oil | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues									2,396	1,901	1,657
Oil | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues									1,179	971	836
Oil | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues									2,271	1,616	1,499
Oil | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Oil | Operating Segments | Canada
Segment Reporting Information [Line Items]
Oil and gas production revenues										110	180
Oil | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Natural Gas
Segment Reporting Information [Line Items]
Oil and gas production revenues									919	959	967
Other Income (Expense):
Revenue from non-customers									58
Natural Gas | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues									339	395	389
Natural Gas | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues									122	92	118
Natural Gas | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues									458	368	314
Natural Gas | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Natural Gas | Operating Segments | Canada
Segment Reporting Information [Line Items]
Oil and gas production revenues										104	146
Natural Gas | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Natural Gas Liquids
Segment Reporting Information [Line Items]
Oil and gas production revenues									583	330	228
Other Income (Expense):
Revenue from non-customers									2
Natural Gas Liquids | Operating Segments | Egypt
Segment Reporting Information [Line Items]
Oil and gas production revenues									13	11	11
Natural Gas Liquids | Operating Segments | North Sea
Segment Reporting Information [Line Items]
Oil and gas production revenues									20	15	16
Natural Gas Liquids | Operating Segments | U.S.
Segment Reporting Information [Line Items]
Oil and gas production revenues									550	287	184
Natural Gas Liquids | Operating Segments | Altus Midstream
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Natural Gas Liquids | Operating Segments | Canada
Segment Reporting Information [Line Items]
Oil and gas production revenues										17	17
Natural Gas Liquids | Intersegment Eliminations & Other
Segment Reporting Information [Line Items]
Oil and gas production revenues									0	0	0
Oil and Gas, Purchased
Segment Reporting Information [Line Items]
Oil and gas production revenues									357	248	152
Operating Expenses:
Gathering, transmission, and processing									$ 340	$ 254	$ 159