Capitalized Exploratory Well Costs and Undeveloped Leasehold Costs (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized Exploratory Well Costs, Beginning of Period	$ 768
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves	6
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves (1)	(203)
Capitalized Exploratory Well Costs, End of Period	571
Exploratory Well Costs Capitalized for a Period of One Year or Less		$ 58	$ 69
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling (1)		513	699
Capitalized Exploratory Well Costs, End of Period	768	$ 571	$ 768
Percentage of divestiture farmed out		35.00%	35.00%
Capitalized undeveloped leasehold cost	2,300
Onshore US [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost	2,200
International [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost	52
Deepwater Gulf of Mexico [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost	86
Gulf of Mexico and Falkland Island [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost	$ 18