Subsequent Events - Narrative (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		0 Months Ended			0 Months Ended
	Sep. 30, 2014 Mcfe	Sep. 30, 2013 Mcfe	Sep. 30, 2014 Mcfe	Sep. 30, 2013 Mcfe	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Boe acre	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] MMBoe	Oct. 14, 2014 Subsequent Event [Member] Southwestern [Member]	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Natural Gas [Member] Mcf	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Natural Gas Liquids [Member] bbl	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Condensate [Member] bbl	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] North Western Virginia and Southern Pennsylvania [Member] well	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Marcellus and Utica Formations [Member] well	Oct. 15, 2014 Subsequent Event [Member] Southwestern [Member] Deposit Received [Member]
Subsequent Event [Line Items]
Significant Acquisitions and Disposals, Acquisition Costs or Sale Proceeds							$ 5,375
Proceeds from Sale of Productive Assets													$ 269
Number Of Net Acres					413,000	413,000
Number of Wells, Gross											1,500	435
Proved Developed and Undeveloped Reserve, Production (Energy)	35,400,000,000	41,900,000,000	112,000,000,000	130,000,000,000	56,000	221
Proved Developed and Undeveloped Reserves, Production								184,000	20,000	5,000
Percentage of Total Proved Reserves								8.00%