Divestitures Narrative (Details) (USD $)	9 Months Ended				3 Months Ended	9 Months Ended	3 Months Ended								9 Months Ended				1 Months Ended		9 Months Ended			1 Months Ended		3 Months Ended			9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Haynesville Shale [Member] acre	Jul. 11, 2013 Northern Eagle Ford Shale [Member] acre	Sep. 30, 2012 Permian Basin [Member]	Sep. 30, 2012 XTO Energy Inc. [Member] acre	Sep. 30, 2012 Utica [Member] acre	Sep. 30, 2013 Payment at Closing [Member] Haynesville Shale [Member]	Sep. 30, 2013 Payment at Closing [Member] Northern Eagle Ford Shale [Member]	Sep. 30, 2013 Payment Remaining [Member] Northern Eagle Ford Shale [Member]	Sep. 30, 2013 Subsequent Payment [Member] Northern Eagle Ford Shale [Member]	Sep. 30, 2013 Scenario, Forecast [Member] Haynesville Shale [Member]	Sep. 30, 2013 Scenario, Forecast [Member] Oil [Member] Boe	Sep. 30, 2013 Scenario, Forecast [Member] Natural Gas [Member] Mcf	Sep. 30, 2013 Excluding Joint Ventures [Member]	Sep. 30, 2012 Excluding Joint Ventures [Member]	Sep. 30, 2013 JV Marcellus, Barnett and Utica	Sep. 30, 2012 JV Marcellus, Barnett and Utica	Jun. 30, 2010 VPP 7 Permian Basin [Member]	Sep. 30, 2012 VPP 7 Permian Basin [Member] Mcfe	Sep. 30, 2013 Corporate Joint Venture [Member]	Sep. 30, 2012 Corporate Joint Venture [Member]	Jun. 30, 2013 Corporate Joint Venture [Member] acre	Dec. 31, 2011 JV Utica	Feb. 28, 2011 JV Niobrara	Jun. 30, 2013 JV Mississippi Lime acre	Jun. 30, 2013 JV Mississippi Lime Payment at Closing [Member]	Jun. 30, 2013 JV Mississippi Lime Payment Remaining [Member]	Sep. 30, 2013 JV Mississippi Lime Payment Remaining [Member]	Jun. 30, 2013 JV Mississippi Lime Closing adjustments between the effective date and the closing date transaction [Member]	Sep. 30, 2013 Corporate VPP [Member]
Business Acquisition [Line Items]
Maximum working interest percentage allowed	2.50%
Gas and Oil Area, Developed, Net			9,600	55,000		60,000	72,000																850,000			425,000
Proceeds from divestitures of proved and unproved properties	$ 2,789,000,000	$ 2,445,000,000			$ 376,000,000	$ 572,000,000	$ 358,000,000	$ 257,000,000	$ 617,000,000	$ 64,000,000	$ 4,000,000	$ 32,000,000			$ 800,000,000	$ 180,000,000
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners																										50.00%
Proved Developed Reserves (Energy)													22							28,000,000
Proceeds from Divestiture of Interest in Joint Venture																	48,000,000	228,000,000	313,000,000		8,049,000,000			610,000,000	570,000,000	1,020,000,000	949,000,000	71,000,000	71,000,000	90,000,000
Percentage of Total Payment by Joint Venture Partner																											93.00%		7.00%
Proved Developed Reserves (Volume)														251
Number of Joint Ventures																					8
Total Drilling Carries																					9,035,000,000			1,422,000,000	697,000,000	0
Oil And Gas Benefit From Drilling Carries																					669,000,000	655,000,000
Gain (Loss) on Sale of Other Assets																															$ 0