Asset Impairments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	$ 15	$ 34	$ 43	$ 131
Deepwater Gulf of Mexico (US Properties) [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	8	18	11	23
Eastern Mediterranean [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	7	14	32	14
North Sea [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	$ 0	$ 2	$ 0	$ 94