Capitalized Exploratory Well Costs and Undeveloped Leasehold Costs (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Sep. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Mar. 31, 2016	Dec. 31, 2015
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			83
Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves			(1)
Capitalized Exploratory Well Cost, Charged to Expense	[1]		(83)
Capitalized Exploratory Well Costs, End of Period		$ 1,209	1,209
Exploratory Well Costs Capitalized for a Period of One Year or Less					$ 91		$ 95
Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling					1,118		1,258
Capitalized Exploratory Well Costs, End of Period		1,209	1,353		$ 1,209		$ 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%
Capitalized undeveloped leasehold cost		105	2,000
Leasehold impairment		81	81	$ 0
Valuation allowance increase		$ 24
Onshore US [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost			1,900
International [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost			32
Deepwater Gulf of Mexico [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Capitalized undeveloped leasehold cost			$ 116
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					$ 97
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					52
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					240
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					184
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					53
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					196
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					84
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					88
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					26
Cyprus Block 12 [Member]
Capitalized Exploratory Well Costs [Roll Forward]
Farmdown					$ (143)		$ (171)
Aging of Capitalized Exploratory Well Costs, Period One [Member] | 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						$ 45
Aging of Capitalized Exploratory Well Costs, Period One [Member] | 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						$ 22

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