Segment Information (Details) (USD $)	3 Months Ended		9 Months Ended		0 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segment	Sep. 30, 2012	Dec. 19, 2012 Equitable Gas and Homeworks	Sep. 30, 2013 Operating segments EQT Production	Sep. 30, 2012 Operating segments EQT Production	Sep. 30, 2013 Operating segments EQT Production	Sep. 30, 2012 Operating segments EQT Production	Sep. 30, 2013 Operating segments EQT Midstream	Sep. 30, 2012 Operating segments EQT Midstream	Sep. 30, 2013 Operating segments EQT Midstream	Sep. 30, 2012 Operating segments EQT Midstream	Sep. 30, 2013 Operating segments Distribution	Sep. 30, 2012 Operating segments Distribution	Sep. 30, 2013 Operating segments Distribution	Sep. 30, 2012 Operating segments Distribution	Sep. 30, 2013 Less intersegment revenues, net	Sep. 30, 2012 Less intersegment revenues, net	Sep. 30, 2013 Less intersegment revenues, net	Sep. 30, 2012 Less intersegment revenues, net	Sep. 30, 2013 Third-party transportation costs	Sep. 30, 2012 Third-party transportation costs	Sep. 30, 2013 Third-party transportation costs	Sep. 30, 2012 Third-party transportation costs	Sep. 30, 2013 Unallocated expenses and Other	Sep. 30, 2012 Unallocated expenses and Other	Sep. 30, 2013 Unallocated expenses and Other	Sep. 30, 2012 Unallocated expenses and Other
Segment Information
Reportable segments number			3
Percentage of ownership interests of Equitable Gas Company, LLC (Equitable Gas) and Equitable Homeworks, LLC (Homeworks) to PNG Companies					100.00%
Operating segments information
Revenues from external customers	$ 506,598,000	$ 364,057,000	$ 1,585,350,000	$ 1,151,821,000		$ 304,231,000	$ 195,289,000	$ 860,874,000	$ 549,334,000	$ 155,677,000	$ 120,484,000	$ 452,731,000	$ 362,630,000	$ 36,118,000	$ 35,649,000	$ 246,281,000	$ 219,343,000	$ (23,744,000)	$ (21,312,000)	$ (79,420,000)	$ (71,110,000)	$ 34,316,000	$ 33,947,000	$ 104,884,000	$ 91,624,000
Operating income	170,548,000	85,948,000	540,478,000	319,538,000		97,600,000	38,528,000	276,753,000	115,270,000	78,533,000	51,021,000	224,993,000	166,907,000	(87,000)	685,000	58,359,000	43,831,000									(5,498,000)	(4,286,000)	(19,627,000)	(6,470,000)
Reconciliation of operating income to net income:
Other income	2,405,000	2,801,000	6,846,000	13,841,000
Interest expense	35,554,000	40,460,000	110,690,000	122,341,000
Income taxes	34,789,000	11,585,000	130,625,000	70,853,000
Net income	102,610,000	36,704,000	306,009,000	140,185,000
Depreciation, depletion, and amortization	175,648,000	131,611,000	493,341,000	354,817,000		150,637,000	108,204,000	419,619,000	289,176,000	18,930,000	17,172,000	55,601,000	46,864,000	6,096,000	6,237,000	18,216,000	18,767,000									(15,000)	(2,000)	(95,000)	10,000
Expenditure for segment assets	454,615,000	361,183,000	1,259,634,000	1,023,503,000		332,370,000	255,223,000	977,394,000	703,834,000	111,593,000	97,135,000	254,205,000	296,698,000	9,710,000	8,164,000	24,873,000	21,066,000									942,000	661,000	3,162,000	1,905,000
Expenditures for segment assets for property acquisitions						$ 20,500,000	$ 20,600,000	$ 162,100,000	$ 95,200,000