Divestitures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Proceeds from Sales of Producing Properties, Acreage and Other Assets	$ 1	$ 20	$ 400
Cumulative Translation Adjustment			383
Restricted cash related to future abandonment liabilities			$ 150