Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	$ 1,386	$ 1,991	$ 2,473	$ 3,650
Operating Income (Loss)	(61)	(147)	(226)	(2,130)
Other Income (Expense):
Gain (loss) on divestitures, net	17	227	16	209
Other	(21)	28	(24)	22
General and administrative	(103)	(111)	(196)	(195)
Transaction, reorganization, and separation	(9)	(66)	(24)	(120)
Financing costs, net	(104)	(117)	(209)	(241)
LOSS FROM CONTINUING OPERATIONS BEFORE INCOME TAXES	(281)	(186)	(663)	(2,455)
Total Assets	24,346	36,802	24,346	36,802	$ 25,500
Asset impairments				2,600
U.S. [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	520	767	929	1,427
Operating Income (Loss)	(109)	(363)	(267)	(2,382)
Other Income (Expense):
Total Assets	12,383	20,367	12,383	20,367
Asset impairments	125	465	166	2,400
Canada [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	73	138	156	271
Operating Income (Loss)	(57)	(78)	(118)	(174)
Other Income (Expense):
Total Assets	2,070	3,932	2,070	3,932
Asset impairments	9	27	10	54
Egypt [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	542	703	934	1,256
Operating Income (Loss)	220	335	261	499
Other Income (Expense):
Total Assets	5,520	7,435	5,520	7,435
Asset impairments		5		267
North Sea [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	251	383	454	696
Operating Income (Loss)	(115)	(40)	(101)	(72)
Other Income (Expense):
Total Assets	4,326	4,488	4,326	4,488
Asset impairments	105	163	105	13
Other International [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	0	0	0	0
Operating Income (Loss)	0	(1)	(1)	(1)
Other Income (Expense):
Total Assets	$ 47	$ 580	$ 47	$ 580