Divestitures (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Divestitures [Abstract]
Proceeds from Sales of Producing Properties, Acreage and Other Assets	$ 761	$ 1,300	$ 1,400
Assets Held-for-Sale, at Carrying Value, Total		310
Liabilities of Assets Held-for-Sale		$ 31