Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Oil and gas production revenues	$ 1,952	$ 3,471	$ 3,590	$ 6,862
Operating Income (Loss)	(5,477)	1,272	(12,787)	2,726
Other Income (Expense):
Derivative instrument gains (losses), net		(174)		(194)
Other	25	(8)	17	9
General and administrative	(111)	(113)	(193)	(221)
Transaction, reorganization, and separation costs	(66)	(14)	(120)	(32)
Financing costs, net	(63)	(52)	(133)	(97)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(5,692)	911	(13,216)	2,191
Total Assets	35,312	52,900	35,312	52,900	$ 55,952
United States [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	767	1,529	1,427	3,034
Operating Income (Loss)	(4,224)	679	(9,546)	1,342
Other Income (Expense):
Total Assets	18,615	31,547	18,615	31,547
Canada [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	138	293	271	611
Operating Income (Loss)	(886)	47	(2,314)	119
Other Income (Expense):
Total Assets	3,585	6,842	3,585	6,842
Egypt [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	664	989	1,196	1,939
Operating Income (Loss)	214	585	318	1,121
Other Income (Expense):
Total Assets	7,679	7,264	7,679	7,264
North Sea [Member]
Segment Reporting Information [Line Items]
Oil and gas production revenues	383	660	696	1,278
Operating Income (Loss)	(581)	(39)	(1,245)	144
Other Income (Expense):
Total Assets	4,838	6,713	4,838	6,713
Other International [Member]
Other Income (Expense):
Total Assets	$ 595	$ 534	$ 595	$ 534