Acquisitions and Divestitures Joint Ventures (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended		1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended	6 Months Ended
	Jun. 30, 2013 JV Mississippi Lime	Jun. 30, 2013 JV Mississippi Lime	Jun. 30, 2013 JV Mississippi Lime Payment at Closing [Member]	Jun. 30, 2013 JV Utica	Jun. 30, 2012 JV Utica	Feb. 28, 2011 JV Niobrara	Jun. 30, 2013 JV Niobrara	Nov. 30, 2010 JV Eagle Ford	Jun. 30, 2013 JV Eagle Ford	Jan. 31, 2010 JV Barnett Shale	Jun. 30, 2013 JV Barnett Shale	Nov. 30, 2008 JVMarcellus	Jun. 30, 2013 JVMarcellus	Sep. 30, 2008 JV Fayetteville	Jun. 30, 2013 JV Fayetteville	Jul. 31, 2008 JV Haynesville And Bossier	Jun. 30, 2013 JV Haynesville And Bossier	Jun. 30, 2013 Corporate Joint Venture [Member]
Joint Ventures [Line Items]
Joint Venture Partner	Sinopec				TOT	CNOOC		CNOOC		TOT		STO		BP		PXP
Joint Venture Date	June 2013				December 2011	February 2011		November 2010		January 2010		November 2008		September 2008		July 2008
Interest Sold	50.00%				25.00%	33.30%		33.30%		25.00%		32.50%		25.00%		20.00%
Proceeds from Divestiture of Interest in Joint Venture	$ 1,110		$ 1,040		$ 610	$ 570		$ 1,120		$ 800		$ 1,250		$ 1,100		$ 1,650		$ 8,140
Total Drilling Carries	0				1,422		697		1,080		1,403	2,125		800		1,508		9,035
Total Cash And Drilling Carry Proceeds		1,040		2,032			1,267		2,200		2,203		3,375		1,900		3,158	17,175
Drilling Carries Remaining		$ 0		$ 836			$ 343		$ 0		$ 0		$ 0		$ 0		$ 0	$ 1,179