Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015		Sep. 30, 2016	Sep. 30, 2015		Dec. 31, 2015	[3]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	$ 1,439	$ 1,606	[1]	$ 3,912	$ 5,256	[1]
Operating Income (Loss)	(688)	(4,041)		(914)	(6,171)
Other Income (Expense):
Gain on divestitures, net	5	(5)	[1]	21	204	[1],[2]
Other	(6)	(75)		(30)	(53)
General and administrative	(102)	(89)	[1]	(298)	(284)	[1]
Transaction, reorganization, and separation	(12)	0	[1]	(36)	(120)	[1]
Financing costs, net	(102)	(160)	[1]	(311)	(401)	[1]
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(905)	(4,370)	[1]	(1,568)	(6,825)	[1]
Total Assets	23,149	31,239		23,149	31,239		$ 25,500
Asset impairments					6,300
Operating Segments [Member] | U.S. [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	524	639		1,453	2,066
Operating Income (Loss)	(17)	(3,582)		(283)	(5,967)
Other Income (Expense):
Total Assets	12,299	15,278		12,299	15,278
Asset impairments	47	3,500		212	5,900
Operating Segments [Member] | Canada [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	87	116		243	387
Operating Income (Loss)	(466)	(292)		(586)	(464)
Other Income (Expense):
Total Assets	1,630	3,627		1,630	3,627
Asset impairments	423	237		433	291
Operating Segments [Member] | Egypt [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	581	534		1,515	1,790
Operating Income (Loss)	263	67		525	569
Other Income (Expense):
Total Assets	5,320	7,535		5,320	7,535
Asset impairments		78			91
Operating Segments [Member] | North Sea [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	247	317		701	1,013
Operating Income (Loss)	(455)	(86)		(557)	(160)
Other Income (Expense):
Total Assets	3,851	4,359		3,851	4,359
Asset impairments	481	105		586	372
Other International [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	0	0		0	0
Operating Income (Loss)	(13)	(148)		(13)	(149)
Other Income (Expense):
Total Assets	$ 49	440		$ 49	440
Asset impairments		$ 148			$ 148

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

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

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