Derivative Instruments (Details) (USD $)	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
Derivatives designated as hedging instruments
Net of tax amount included in OCI	$ (1,132,000)				$ (1,276,000)				$ (1,132,000)	$ (1,276,000)
Natural Gas Hedging Instruments
Deferred net gains in accumulated other comprehensive income (loss), net of tax	61,700,000				138,200,000				61,700,000	138,200,000
Net unrealized gains on derivative commodity instruments	27,200,000								27,200,000
Margin deposits with brokers	300,000				700,000				300,000	700,000
Additional collateral limit for below investment grade derivative instruments, as a percentage of the derivative liability									100.00%
Aggregate fair value of derivative instruments with credit-risk related contingencies	8,800,000								8,800,000
Collateral posted	0								0
Reduction in operating revenue	493,429,000	479,606,000	473,093,000	415,883,000	406,273,000	337,916,000	298,742,000	334,291,000	1,862,011,000	1,377,222,000	1,323,829,000
Increase of accumulated OCI									(54,844,000)	(88,594,000)	150,037,000
Correction of error related to the accounting for a derivative instrument put premium
Natural Gas Hedging Instruments
Increase of accumulated OCI							5,100,000
Decrease of deferred tax expense							3,100,000
Correction of error related to the accounting for a derivative instrument put premium | EQT Production segment
Natural Gas Hedging Instruments
Reduction in operating revenue							(8,200,000)
Interest rate swaps settled
Derivatives designated as hedging instruments
Amount of gain (loss) recognized in OCI (effective portion), net of tax											(1,400,000)
Number of swaps settled											1
Term over which loss is recorded in OCI to be recognized											10 years
Interest rate swaps
Derivatives designated as hedging instruments
Amount of gain (loss) recognized in OCI (effective portion), net of tax										7,100,000
Amount of gain (loss) reclassified from accumulated OCI, net of tax into operating revenues (effective portion)										23,300,000
Amount of reversal which had previously been deferred in accumulated OCI, net of tax					13,300,000					13,300,000
Number of forward-starting interest rate swaps entered into by the entity											2
Net of tax amount included in OCI											6,200,000
Commodity derivatives
Natural Gas Hedging Instruments
Absolute quantities of derivative commodity instruments that have been designated and qualify as cash flow or fair value hedges (in Bcf)										8,000
Margin deposits with brokers	266,000				736,000				266,000	736,000
Cash flow hedges | Interest rate derivatives
Derivatives designated as hedging instruments
Amount of gain (loss) recognized in OCI (effective portion), net of tax										(7,138,000)	(7,573,000)
Amount of (loss) reclassified from accumulated OCI, net of tax, into interest expense due to forecasted transactions no longer being probable										(13,266,000)
Amount of gain (loss) reclassified from accumulated OCI, net of tax into operating revenues (effective portion)									(144,000)	(241,000)	(140,000)
Cash flow hedges | Commodity derivatives
Derivatives designated as hedging instruments
Pre-tax gain recognized in operating revenues for de-designation of derivative instruments related to sale of certain energy marketing contracts									1,000,000
Amount of gain (loss) recognized in OCI (effective portion), net of tax									10,669,000	86,259,000	239,019,000
Amount of gain (loss) reclassified from accumulated OCI, net of tax into operating revenues (effective portion)									87,158,000	180,137,000	72,179,000
Amount of (loss) recognized in operating revenues (ineffective portion)									(21,335,000)	(75,000)	(181,000)
Natural Gas Hedging Instruments
Absolute quantities of derivative commodity instruments that have been designated and qualify as cash flow or fair value hedges (in Bcf)									398,000	365,000
Fair value hedges | Commodity derivatives
Derivatives designated as hedging instruments
Amount of (loss) gain recognized in operating revenues for fair value commodity contracts									(1,341,000)	3,878,000	12,263,000
Fair value (loss) gain recognized in operating revenues for inventory designated as hedged item									386,000	3,292,000	(6,059,000)
Amount of gain (loss) recognized in income due to exclusion of the spot/forward differential from the assessment of effectiveness									500,000	7,600,000	7,600,000
Amount of gain (loss) recognized in income due to changes in basis									(1,500,000)	(400,000)	(1,400,000)
Not designated as hedging instruments
Derivatives not designated as hedging instruments:
Amount of (loss) gain recognized in operating revenues									$ 2,834,000	$ 2,176,000	$ 4,209,000