Capitalized Exploratory Well Costs and Undeveloped Leasehold Costs (Details) - USD ($) $ in Millions		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]
Capitalized undeveloped leasehold cost		$ 2,100
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized Exploratory Well Costs, Beginning of Period		1,353
Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves		68
Capitalized Exploratory Well Cost, Other	[1]	(143)
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves		(4)
Capitalized Exploratory Well Cost, Charged to Expense	[2]	(82)
Capitalized Exploratory Well Costs, End of Period		1,192
Exploratory Well Costs Capitalized for a Period of One Year or Less			$ 86	$ 95
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			1,106	1,258
Capitalized Exploratory Well Costs, End of Period		1,353	$ 1,192	$ 1,353
Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling			13	14
Percentage of divestiture farmed out			35.00%	35.00%
Onshore US [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]
Capitalized undeveloped leasehold cost		1,900
International [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]
Capitalized undeveloped leasehold cost		57
Deepwater Gulf of Mexico [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]
Capitalized undeveloped leasehold cost		$ 195
Katmai Deepwater Gulf Of Mexico [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			$ 95
Troubadour Deepwater Gulf of Mexico [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			51
Diega (including Carmen) Offshore Equatorial Guinea [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			237
Carla Offshore Equatorial Guinea [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			182
Felicita/Yolanda Offshore Equatorial Guinea [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			66
YoYo Offshore Cameron [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			52
Leviathan Offshore Israel [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			194
Leviathan-1 Deep Offshore Israel [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			83
Dalit Offshore Israel [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			31
Cyprus [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			87
Other - Projects of $20 million or less each [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling			$ 28

[1] Represents our farm-out of a 35% interest in Block 12 offshore Cyprus to a new partner.

[2] Includes amounts related to contract termination offshore Falkland Islands, Dolphin 1 exploratory well offshore Israel, and Silvergate exploratory well deepwater Gulf of Mexico