Asset Impairments (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Oil and Gas Properties	$ 86	$ 104	$ 757
Piceance (Onshore US)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Oil and Gas Properties	0	39	487
South Raton (Deepwater Gulf of Mexico)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Oil and Gas Properties	0	34	0
Mari-B (Offshore Israel)
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Oil and Gas Properties	47	31	0
Other Onshore US Properties
Impaired Long-Lived Assets Held and Used [Line Items]
Impairment of Oil and Gas Properties	$ 39	$ 0	$ 270