Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Oil and gas production revenues	$ 1,572	$ 3,181	$ 5,162	$ 10,043
Operating Income (Loss)	(5,706)	(372)	(18,493)	2,354
Other Income (Expense):
Derivative instrument gains (losses), net		273		79
Other	(76)	(13)	(59)	(4)
General and administrative	(86)	(111)	(279)	(332)
Impairments	(367)		(367)
Transaction, reorganization, and separation		(34)	(120)	(66)
Financing costs, net	(107)	(60)	(240)	(157)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(6,342)	(317)	(19,558)	1,874
Total Assets	27,812	52,340	27,812	52,340	$ 55,952
United States [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	639	1,481	2,066	4,515
Operating Income (Loss)	(4,253)	(988)	(13,800)	354
Other Income (Expense):
Total Assets	12,806	30,613	12,806	30,613
Canada [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	116	268	387	879
Operating Income (Loss)	(1,022)	11	(3,336)	131
Other Income (Expense):
Total Assets	2,438	7,100	2,438	7,100
Egypt [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	500	910	1,696	2,849
Operating Income (Loss)	43	481	361	1,601
Other Income (Expense):
Total Assets	7,788	7,246	7,788	7,246
North Sea [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	317	522	1,013	1,800
Operating Income (Loss)	(474)	124	(1,718)	268
Other Income (Expense):
Total Assets	4,323	6,824	4,323	6,824
Other International [Member]
Other Income (Expense):
Total Assets	$ 457	$ 557	$ 457	$ 557