Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Oil and gas production revenues									$ 5,367	$ 6,510	[1]	$ 12,795	[1]
Lease operating expenses									1,494	1,854	[1]	2,238	[1]
Gathering and transportation									200	211	[1]	273	[1]
Taxes other than income									126	282	[1]	577	[1]
Depreciation, depletion, and amortization									2,618	3,300	[2]	4,526	[2]
Exploration									473	2,771	[1]	2,499	[1]
Asset retirement obligation accretion									156	145	[1],[2]	154	[1],[2]
Impairments									1,103	9,472		7,102
Operating Income (Loss)									(803)	(11,525)		(4,574)
Other Income (Expense):
Gain (loss) on divestiture	$ 0	$ 5	$ 17	$ (1)	$ 77	$ (5)	$ 227	$ (18)	21	281	[1],[2]	(1,608)	[1],[2]
Other									(34)	98		285
General and administrative									(410)	(380)	[1]	(453)	[1]
Transaction, reorganization, and separation									(39)	(132)	[1]	(67)	[1]
Financing costs, net									(417)	(511)	[1]	(413)	[1]
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES									(1,682)	(12,169)	[1]	(6,830)	[1]
Net property and equipment	18,867				20,838				18,867	20,838		32,154
Total Assets	22,519				25,500				22,519	25,500		38,165
Additions to Net Property and Equipment	1,681				4,106				1,681	4,106		10,725
Operating Segments [Member] | United States [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues									1,997	2,637		5,744
Lease operating expenses									553	739		921
Gathering and transportation									80	68		93
Taxes other than income									139	184		350
Depreciation, depletion, and amortization									1,138	1,558		2,408
Exploration									285	2,145		2,113
Asset retirement obligation accretion									34	28		43
Impairments									80	6,266		2,622
Operating Income (Loss)									(312)	(8,351)		(2,806)
Other Income (Expense):
Net property and equipment	11,168				11,753				11,168	11,753		19,507
Total Assets	12,403				12,782				12,403	12,782		21,487
Additions to Net Property and Equipment	926				2,099				926	2,099		7,006
Operating Segments [Member] | Canada [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues									343	498		1,092
Lease operating expenses									181	244		384
Gathering and transportation									68	89		123
Taxes other than income									20	26		31
Depreciation, depletion, and amortization									183	301		439
Exploration									88	231		162
Asset retirement obligation accretion									47	43		39
Impairments									367	1,593		2,412
Operating Income (Loss)									(611)	(2,029)		(2,498)
Other Income (Expense):
Net property and equipment	1,464				2,074				1,464	2,074		4,197
Total Assets	1,591				2,225				1,591	2,225		4,728
Additions to Net Property and Equipment	34				403				34	403		1,358
Operating Segments [Member] | Egypt [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues									2,057	2,095		3,643
Lease operating expenses									446	522		499
Gathering and transportation									44	45		40
Taxes other than income									0	9		11
Depreciation, depletion, and amortization									778	927		872
Exploration									48	154		112
Impairments									1	1,255		173
Operating Income (Loss)									740	(817)		1,936
Other Income (Expense):
Net property and equipment	3,362				3,712				3,362	3,712		5,141
Total Assets	4,893				6,165				4,893	6,165		6,926
Additions to Net Property and Equipment	459				862				459	862		1,293
Operating Segments [Member] | North Sea [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues									970	1,280		2,316
Lease operating expenses									314	349		434
Gathering and transportation									8	9		17
Taxes other than income									(33)	63		185
Depreciation, depletion, and amortization									519	514		807
Exploration									37	237		119
Asset retirement obligation accretion									75	74		72
Impairments									655	211		1,895
Operating Income (Loss)									(605)	(177)		(1,213)
Other Income (Expense):
Net property and equipment	2,834				3,263				2,834	3,263		3,300
Total Assets	3,584				4,280				3,584	4,280		4,480
Additions to Net Property and Equipment	260				715				260	715		1,060
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion, and amortization												0
Exploration									15	4		(7)
Impairments									0	147
Operating Income (Loss)									(15)	(151)		7
Other Income (Expense):
Net property and equipment	39				36				39	36		9
Total Assets	48				48				48	48		544
Additions to Net Property and Equipment	$ 2				$ 27				$ 2	$ 27		$ 8

[1] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.

[2] Financial information for 2015 and 2014 has been recast to reflect retrospective application of the successful efforts method of accounting. See Note 1.