Asset Impairments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	$ 33	$ 63	$ 164	$ 63
Deepwater Gulf of Mexico (US Properties) [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	2	16	25	16
Piceance (Onshore US) [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	31	0	31	0
Mari-B (Offshore Israel)
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	0	47	14	47
McCulloch and Other North Sea Properties [Member]
Impaired Long-Lived Assets Held and Used [Line Items]
Asset Impairments	$ 0	$ 0	$ 94	$ 0