Divestitures (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Business Combinations [Abstract]
Proceeds from Sales of Producing Properties, Acreage and Other Assets	$ 569	$ 761	$ 1,300
Cumulative translation adjustments	383
Restricted cash related to future abandonment liabilities	$ 150