CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Operating Revenues:
Gas sales	$ 2,080,241		$ 1,856,241		$ 1,578,256
Gas marketing	714,123		615,913		488,663
Oil sales	9,085		13,111		6,843
Gas gathering	149,973		122,912		74,281
Other	(516)		2,486		(2,264)
Total Operating Revenues	2,952,906		2,610,663		2,145,779
Operating Costs and Expenses:
Gas purchases - Midstream Services	709,091		611,161		482,836
Operating expenses	240,944		191,771		136,541
General and administrative expenses	158,041		145,563		122,618
Depreciation, depletion and amortization	704,511		590,332		493,658
Impairment of natural gas and oil properties	0		0		907,812
Taxes, other than income taxes	65,518		50,608		37,280
Total operating costs and expenses	1,878,105		1,589,435		2,180,745
Operating Income (Loss)	1,074,801		1,021,228		(34,966)
Interest Expense:
Interest on debt	65,421		57,144		55,581
Other interest charges	4,306		1,935		3,266
Interest capitalized	(45,652)		(32,916)		(40,209)
Total Interest Expense	24,075	[1]	26,163	[1]	18,638	[1]
Other Income, Net	264		427		1,449
Income (Loss) Before Income Taxes	1,050,990		995,492		(52,155)
Provision (Benefit) for Income Taxes:
Current	4,198		11,939		(64,969)
Deferred	409,023		379,720		48,606
Provision (benefit) for income taxes	413,221	[1]	391,659	[1]	(16,363)
Net Income (Loss)	637,769		603,833		(35,792)
Less: Net Loss Attributable to Noncontrolling Interest	0		(285)		(142)
Net Income (Loss) Attributable to Southwestern Energy	$ 637,769		$ 604,118		$ (35,650)
Earnings Per Share:
Net income (loss) attributable to Southwestern Energy stockholders - Basic	$ 1.84		$ 1.75		$ (0.10)
Net income (loss) attributable to Southwestern Energy stockholders - Diluted	$ 1.82		$ 1.73		$ (0.10)
Weighted Average Common Shares Outstanding:
Basic	347,205,316		345,581,568		343,420,568
Effect of:
Stock options	2,475,053		3,512,241		0
Restricted stock awards	241,044		216,857		0
Diluted	349,921,413		349,310,666		343,420,568

[1] (1) Interest income, interest expense and the provision (benefit) for income taxes by segment are an allocation of corporate amounts as cash equivalents, debt and income tax expense allocated as they are incurred at the corporate level.