Segment Information (Details) (USD $)	3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 segment	Jun. 30, 2012	Dec. 19, 2012 Equitable Gas and Homeworks	Jun. 30, 2013 EQT Production	Jun. 30, 2012 EQT Production	Jun. 30, 2013 EQT Production	Jun. 30, 2012 EQT Production	Jun. 30, 2013 EQT Midstream	Jun. 30, 2012 EQT Midstream	Jun. 30, 2013 EQT Midstream	Jun. 30, 2012 EQT Midstream	Jun. 30, 2013 Distribution	Jun. 30, 2012 Distribution	Jun. 30, 2013 Distribution	Jun. 30, 2012 Distribution	Jun. 30, 2013 Other	Jun. 30, 2012 Other	Jun. 30, 2013 Other	Jun. 30, 2012 Other	Jun. 30, 2013 Less intersegment revenues, net	Jun. 30, 2012 Less intersegment revenues, net	Jun. 30, 2013 Less intersegment revenues, net	Jun. 30, 2012 Less intersegment revenues, net	Jun. 30, 2013 Unallocated expenses	Jun. 30, 2012 Unallocated expenses	Jun. 30, 2013 Unallocated expenses	Jun. 30, 2012 Unallocated expenses
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
Third-party transportation costs	$ 34,827,000	$ 30,470,000	$ 70,568,000	$ 57,677,000
Revenues from external customers	520,092,000	337,804,000	1,078,752,000	787,764,000		306,132,000	158,649,000	556,643,000	354,045,000	150,366,000	120,098,000	297,054,000	242,146,000	56,345,000	48,273,000	210,163,000	183,694,000					(27,578,000)	(19,686,000)	(55,676,000)	(49,798,000)
Operating income	171,295,000	81,404,000	369,930,000	233,590,000		105,056,000	17,704,000	179,153,000	76,742,000	72,246,000	59,750,000	146,460,000	115,886,000	6,170,000	6,376,000	58,446,000	43,146,000									(12,177,000)	(2,426,000)	(14,129,000)	(2,184,000)
Reconciliation of operating income to net income:
Other income	2,111,000	5,249,000	4,441,000	11,040,000
Interest expense	37,384,000	40,629,000	75,136,000	81,881,000
Income taxes	41,904,000	14,578,000	95,836,000	59,268,000
Net income	94,118,000	31,446,000	203,399,000	103,481,000
Depreciation, depletion, and amortization	168,577,000	115,681,000	317,693,000	223,206,000		144,073,000	94,405,000	268,982,000	180,972,000	18,452,000	14,984,000	36,671,000	29,692,000	6,072,000	6,287,000	12,120,000	12,530,000	(20,000)	5,000	(80,000)	12,000
Expenditure for segment assets	500,762,000	392,733,000	805,019,000	662,320,000		398,078,000	264,926,000	645,024,000	448,611,000	91,254,000	119,925,000	142,612,000	199,563,000	9,558,000	7,439,000	15,163,000	12,902,000	1,872,000	443,000	2,220,000	1,244,000
Expenditures for segment assets for property acquisitions						$ 128,900,000	$ 56,500,000	$ 141,600,000	$ 74,600,000