Business Segment Information - Financial Segment Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	$ 1,346	$ 1,386	$ 2,858	$ 2,473
Operating Income (Loss)	180	(61)	545	(226)
Other Income (Expense):
Gain (loss) on divestitures	(21)	17	320	16
Other	59	(21)	84	(24)
General and administrative	(106)	(103)	(209)	(196)
Transaction, reorganization, and separation	(4)	(9)	6	(24)
Financing costs, net	(99)	(104)	(199)	(209)
NET INCOME (LOSS) BEFORE INCOME TAXES	9	(281)	547	(663)
Total Assets	22,602	24,346	22,602	24,346	$ 22,519
Operating Segments [Member] | United States [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	491	520	1,043	929
Operating Income (Loss)	(17)	(109)	43	(267)
Other Income (Expense):
Total Assets	12,530	12,383	12,530	12,383
Asset impairments	38	125	52	166
Operating Segments [Member] | Canada [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	93	73	195	156
Operating Income (Loss)	(18)	(57)	(31)	(118)
Other Income (Expense):
Total Assets	1,476	2,070	1,476	2,070
Asset impairments	1	9	2	10
Operating Segments [Member] | Egypt [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	521	542	1,112	934
Operating Income (Loss)	213	220	514	261
Other Income (Expense):
Total Assets	4,778	5,520	4,778	5,520
Operating Segments [Member] | North Sea [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	241	251	508	454
Operating Income (Loss)	4	(115)	42	(101)
Other Income (Expense):
Total Assets	3,772	4,326	3,772	4,326
Asset impairments		105	8	105
Other International [Member]
Segment Reporting Information [Line Items]
Oil and Gas Production Revenues	0	0	0	0
Operating Income (Loss)	(2)	0	(23)	(1)
Other Income (Expense):
Total Assets	$ 46	$ 47	$ 46	$ 47