Asset Impairments Impaired Long-Lived Assets Held and Used- text (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2015	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	$ 5	$ 31	$ 533	$ 500	$ 86
Other (Onshore US)
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments			481
Gulf of Mexico and Eastern Mediterranean
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments			$ 47
United States
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments				250
South Raton (Deepwater Gulf of Mexico)
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments				74
Other Deepwater Gulf of Mexico
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments				$ 51