Quarterly Results (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Quarterly Financial Data [Abstract]
Operating Revenues	$ 907,089	$ 868,366	$ 862,041	$ 733,649	$ 777,355	$ 691,727	$ 606,076	$ 654,835	$ 3,371,145	$ 2,729,993		$ 2,951,332
Operating income (loss)	317,117	309,229	325,317	251,960	(572,947)	(65,959)	(646,046)	184,326	1,203,623	(1,100,626)	[1]	1,073,227
Net income (loss)	$ 144,490	$ 185,867	$ 245,631	$ 127,515	$ (355,583)	$ (54,053)	$ (405,132)	$ 107,704	$ 703,503	$ (707,064)		$ 637,769
Earnings per share attributable to Southwestern Energy stockholders - Basic	$ 0.41	$ 0.53	$ 0.70	$ 0.36	$ (1.02)	$ (0.16)	$ (1.16)	$ 0.31	$ 2.01	$ (2.03)		$ 1.84
Earnings per share attributable to Southwestern Energy stockholders - Diluted	$ 0.41	$ 0.53	$ 0.70	$ 0.36	$ (1.02)	$ (0.16)	$ (1.16)	$ 0.31	$ 2.00	$ (2.03)		$ 1.82

[1] The operating loss for the E&P segment for the twelve months ended December 31, 2012 includes a $1,939.7 million non-cash ceiling test impairment of our natural gas and oil properties.