Derivative Instruments (Details) (USD $)	3 Months Ended	6 Months Ended
Jun. 30, 2011 BillionsCubicFeet	Jun. 30, 2010	Jun. 30, 2011 segments BillionsCubicFeet	Jun. 30, 2010	Dec. 31, 2010 BillionsCubicFeet
Derivatives designated as cash flow hedges
Amount of (loss) gain recognized in other comprehensive income (OCI) (effective portion), net of tax	$ 33,253,000	$ (16,293,000)	$ 37,452,000	$ 61,226,000
Amount of gain reclassified from accumulated OCI into income (effective portion), net of tax	9,918,000	14,111,000	26,823,000	28,218,000
Amount of (loss) gain recognized in income (ineffective portion)	364,000	(2,414,000)	(261,000)	(613,000)
Derivatives designated as fair value hedges
Amount of gain (loss) recognized in income for fair value commodity contracts	1,363,000		(533,000)
Fair value gain (loss) recognized in income for inventory designated as hedged item	60,000		1,693,000
Derivatives not designated as hedging instruments:
Amount of gain (loss) recognized in income	856,000	212,000	(823,000)	89,000
Unrealized hedge gains reclassified into earnings		0		2,600,000
Amount of gain recognized in income due to exclusion of the spot/forward differential from the assessment of effectiveness	2,100,000		1,500,000
Amount of loss recognized in income due to changes in basis	700,000		300,000
Asset derivatives
Derivatives designated as hedging instruments	138,004,000		138,004,000		141,834,000
Derivatives not designated as hedging instruments	73,982,000		73,982,000		83,505,000
Total asset derivatives	211,986,000		211,986,000		225,339,000
Liability derivatives
Derivatives designated as hedging instruments	3,104,000		3,104,000		12,097,000
Derivatives not designated as hedging instruments	94,427,000		94,427,000		94,624,000
Total liability derivatives	97,531,000		97,531,000		106,721,000
Absolute quantities of derivative commodity instruments that have been designated and qualify as cash flow hedges (in Bcf)	240		240		181
Absolute quantities of the derivative commodity instruments that have been designated and qualify as fair value hedges (in Bcf)	6		6
Deferred net gains in accumulated other comprehensive income (loss), net of tax	75,900,000		75,900,000		65,200,000
Net unrealized gains on derivative commodity instruments	34,800,000		34,800,000
Margin deposits with brokers	1,600,000		1,600,000
Margin deposits remitted by brokers with company					500,000
Additional collateral limit for below investment grade derivative instruments, as a percentage of the derivative liability (as a percent)			100.00%
Aggregate fair value of derivative instruments with credit-risk related contingencies	4,600,000		4,600,000
Additional collateral for downgrade below investment grade	$ 4,600,000		$ 4,600,000

Accumulated change, net of tax, in accumulated gains and losses from derivative instruments designated and qualified as the effective portion of cash flow hedges, excluding certain interest rate swap transactions.

Name:	eqt_AccumulatedOtherComprehensiveIncomeLossCumulativeChangesInDeferredNetGainLossFromCashFlowHedgesEffectNetOfTax
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The upper limit of the percentage of derivative liability that the entity may be required to post with counterparties.

+ Details

Name:	eqt_AdditionalCollateralAsPercentageOfDerivativeLiabilityUpperLimit
Namespace Prefix:	eqt
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	eqt_AssetDerivativesAbstract
Namespace Prefix:	eqt
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The net gain relating to the spot/forward differential excluded from the assessment of effectiveness.

+ Details

Name:	eqt_GainFromExclusionOfSpotForwardDifferentialFromAssessmentOfEffectiveness
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total amount of gain (loss) derived from fair value adjustment recognized in income for inventory designated as hedged item in earnings in the period.

+ Details

Name:	eqt_GainLossOnCommodityContractsFairValueHedgesForInventory
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Total amount of gain (loss) derived from commodity contracts designated as fair value hedges recognized in earnings in the period.

+ Details

Name:	eqt_GainLossOnCommodityContractsFairValueHedgesRecognizedInEarnings
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	eqt_LiabilityDerivativesAbstract
Namespace Prefix:	eqt
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The net loss relating to changes in basis excluded from the assessment of effectiveness.

+ Details

Name:	eqt_LossFromChangeInBasis
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of cash remitted from a broker or counterparty as security for a trading or derivatives securities position.

+ Details

Name:	eqt_MarginDepositLiabilities
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of unrealized hedge gains reclassified into earnings to offset against the lower of cost or market adjustments on hedged items.

+ Details

Name:	eqt_PriceRiskDerivativeGainLossReclassifiedFromAccumulatedOtherComprehensiveIncomeIntoIncomeCostOrMarketOnHedgedItem
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of unrealized gain (loss) arising from the change in fair value of price risk derivatives designated as cash flow hedging instruments recorded in accumulated other comprehensive income in the period, after taxes, to the extent that the cash flow hedge is determined to be effective.

+ Details

Name:	eqt_UnrealizedGainLossOnPriceRiskCashFlowDerivativesAfterTax
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44D
-Subparagraph c

+ Details

Name:	us-gaap_AdditionalCollateralAggregateFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_CashFlowHedgesDerivativeInstrumentsAtFairValueNetAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate fair value amounts of derivative instruments that contain credit-risk-related contingent features that are in a net liability position at the end of the reporting period. For nonderivative instruments that are designated and qualify as hedging instruments, the fair value amounts are the carrying value of the nonderivative hedging instrument, including the adjustment for the foreign currency transaction gain or loss on that instrument.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44D
-Subparagraph b

+ Details

Name:	us-gaap_DerivativeNetLiabilityPositionAggregateFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of price risk derivatives not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44

+ Details

Name:	us-gaap_GainLossOnPriceRiskDerivativeInstrumentsNotDesignatedAsHedgingInstruments
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The net gain (loss) recognized in earnings during the reporting period due to the ineffectiveness on price risk cash flow and fair value hedges

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45

+ Details

Name:	us-gaap_GainLossOnPriceRiskHedgeIneffectiveness
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.

+ Details

Name:	us-gaap_MarginDepositAssets
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate notional amount of price risk derivatives designated as a cash flow hedge with notional amounts expressed in nonmonetary units. For example the number of barrels specified in a fuel oil forward purchase contract.

+ Details

Name:	us-gaap_NonmonetaryNotionalAmountOfPriceRiskCashFlowHedgeDerivatives
Namespace Prefix:	us-gaap
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Aggregate notional amount of price risk derivatives designated as a fair value hedge with notional amounts expressed in nonmonetary units. For example the number of barrels specified in a fuel oil forward purchase contract.

+ Details

Name:	us-gaap_NonmonetaryNotionalAmountOfPriceRiskFairValueHedgeDerivatives
Namespace Prefix:	us-gaap
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all price risk derivative assets designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskCashFlowHedgeAssetAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of net gains (losses) on price risk cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-Subparagraph b(1)

+ Details

Name:	us-gaap_PriceRiskCashFlowHedgeGainLossReclassifiedToEarningsNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Fair value as of the balance sheet date of all price risk derivative liabilities designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskCashFlowHedgeLiabilityAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The estimated net amount of unrealized gains (losses) on price risk cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45
-Subparagraph b(2)

+ Details

Name:	us-gaap_PriceRiskCashFlowHedgeUnrealizedGainLossToBeReclassifiedDuringNext12Months
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of price risk derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets on the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskDerivativeAssetsAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all price risk derivative assets not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsAssetAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of all price risk derivative liabilities not designated as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskDerivativeInstrumentsNotDesignatedAsHedgingInstrumentsLiabilityAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value as of the balance sheet date of price risk derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities on the balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 17

+ Details

Name:	us-gaap_PriceRiskDerivativeLiabilitiesAtFairValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_SummaryOfFairValueHedgeActivityAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration