Segment Information (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenue from External Customer [Line Items]
Revenue, Net	$ 10,846	$ 11,325	$ 11,966
Crude oil and condensate [Member]
Revenue from External Customer [Line Items]
Revenue, Net	8,170	8,688	9,301
Natural Gas Liquids [Member]
Revenue from External Customer [Line Items]
Revenue, Net	371	313	201
Natural gas [Member]
Revenue from External Customer [Line Items]
Revenue, Net	693	693	835
Synthetic crude oil [Member]
Revenue from External Customer [Line Items]
Revenue, Net	1,525	1,542	1,409
Miscellaneous other [Member]
Revenue from External Customer [Line Items]
Revenue, Net	$ 87	$ 89	$ 220