Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Operating segments information
Reportable segments number			3
Revenues from external customers	$ 336,720,000	$ 257,335,000	$ 1,141,391,000	$ 951,490,000
Operating income	134,841,000	88,182,000	485,638,000	335,824,000
Reconciliation of operating income to net income:
Gain on dispositions	180,143,000		202,928,000
Other income	3,098,000	2,924,000	27,948,000	8,551,000
Interest expense	32,503,000	33,861,000	98,642,000	102,075,000
Income taxes	106,665,000	20,723,000	228,949,000	87,713,000
Net income	178,914,000	36,522,000	388,923,000	154,587,000
Depreciation, depletion and amortization	87,343,000	68,548,000	247,627,000	195,644,000
Capital expenditures	347,645,000	340,151,000	985,171,000	1,093,698,000
EQT Production
Operating segments information
Revenues from external customers	207,500,000	131,791,000	577,352,000	395,182,000
Operating income	98,936,000	55,651,000	281,024,000	169,797,000
Reconciliation of operating income to net income:
Depreciation, depletion and amortization	66,947,000	46,658,000	186,680,000	131,036,000
Capital expenditures	255,151,000	267,154,000	800,029,000	929,225,000
Expenditures for segment assets for liabilities assumed	92,600,000		92,600,000
Expenditures for segment assets for undeveloped property acquisitions					230,700,000
EQT Midstream
Operating segments information
Revenues from external customers	122,614,000	144,634,000	395,477,000	436,225,000
Operating income	41,673,000	35,858,000	160,549,000	130,263,000
Reconciliation of operating income to net income:
Depreciation, depletion and amortization	14,093,000	15,705,000	43,097,000	46,240,000
Capital expenditures	81,227,000	59,499,000	156,832,000	138,479,000
Distribution
Operating segments information
Revenues from external customers	49,175,000	53,208,000	313,366,000	338,812,000
Operating income	2,463,000	644,000	64,758,000	52,353,000
Reconciliation of operating income to net income:
Depreciation, depletion and amortization	6,534,000	6,057,000	18,414,000	18,067,000
Capital expenditures	10,149,000	9,382,000	25,179,000	21,107,000
Other.:
Reconciliation of operating income to net income:
Depreciation, depletion and amortization	(231,000)	128,000	(564,000)	301,000
Capital expenditures	1,118,000	4,116,000	3,131,000	4,887,000
Less: intersegment revenues
Operating segments information
Revenues from external customers	(42,569,000)	(72,298,000)	(144,804,000)	(218,729,000)
Unallocated expenses
Operating segments information
Operating income	$ (8,231,000)	$ (3,971,000)	$ (20,693,000)	$ (16,589,000)