Impairments - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Property, Plant, and Equipment [Line Items]
Impairment of unproved properties	$ 1,466	$ 45
Net book value	$ 28,516		$ 32,168
Percent decline in price assumption for impairment analysis	10.00%
Unproved Gulf of Mexico Properties [Member]
Property, Plant, and Equipment [Line Items]
Impairment of unproved properties	$ 555
Unproved Shenandoah Properties [Member]
Property, Plant, and Equipment [Line Items]
Impairment of unproved properties	463
Certain International Asset Group at Risk for Impairment [Member]
Property, Plant, and Equipment [Line Items]
Net book value	2,100
Potential non-cash impairments that could be recognized in the future, in excess of	800
Certain U.S. Onshore Asset Groups at Risk for Impairment [Member]
Property, Plant, and Equipment [Line Items]
Net book value	1,000
Potential non-cash impairments that could be recognized in the future, in excess of	$ 500