The approximate area of acquisition by the entity.

No definition available.

Name:	eqt_AssetAcquisitionAreaOfProperty
Namespace Prefix:	eqt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Length of the gathering system acquired, with associated rights of way.

+ References

No definition available.

+ Details

Name:	eqt_AssetAcquisitionLengthOfGatheringSystem
Namespace Prefix:	eqt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of wells acquired.

+ References

No definition available.

+ Details

Name:	eqt_AssetAcquisitionNumberOfVerticalWells
Namespace Prefix:	eqt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of acquisition cost of a business combination allocated to a liability for a discounted sales agreement.

+ References

No definition available.

+ Details

Name:	eqt_BusinessAcquisitionPurchasePriceAllocationDiscountedSalesLiability
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The amount of acquisition cost of a business combination allocated to a swap liability assumed.

+ References

No definition available.

+ Details

Name:	eqt_BusinessAcquisitionPurchasePriceAllocationSwapLiability
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cost of acquired assets paid in cash.

+ References

No definition available.

+ Details

Name:	eqt_CostOfAcquiredAssetsCashPortion
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total cost of acquired assets paid through equity securities issued.

+ References

No definition available.

+ Details

Name:	eqt_CostOfAcquiredAssetsStockPortion
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The total cost of acquired assets including the cash paid and equity securities issued.

+ References

No definition available.

+ Details

Name:	eqt_CostOfAcquiredAssetsTotal
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents the percentage of net profits received from sale of natural gas and oil from natural gas producing properties.

+ References

No definition available.

+ Details

Name:	eqt_PercentageOfNetProfitsInterestSold
Namespace Prefix:	eqt_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash proceeds from sale of net profits interest in producing properties.

+ References

No definition available.

+ Details

Name:	eqt_ProceedsFromSaleOfNetProfitsInterest
Namespace Prefix:	eqt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of acquisition cost of a business combination allocated to liabilities assumed.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 37

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 98-1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_BusinessAcquisitionPurchasePriceAllocationLiabilitiesAssumed
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents the sum of the: (1) acquisition-date fair value of the total consideration transferred which consists of the sum of the acquisition-date fair values of the assets transferred by the acquirer, the liabilities incurred by the acquirer to former owners of the acquiree, and the equity interests issued by the acquirer and (2) the acquisition-date fair value of any equity interest in the acquiree held by the acquirer prior to the business combination (for example, a step acquisition).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph q

-Clause 1

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 68

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6911361&loc=d3e6927-128479

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferredIncludingEquityInterestInAcquireeHeldPriorToCombination
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

In a business combination achieved in stages, this element represents the acquisition-date fair value of the equity interest in the acquiree held by the acquirer immediately before the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Number 141R

-Paragraph 68

-Subparagraph q(1)

-Name Statement of Financial Accounting Standard (FAS)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)(1)

-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

In a business combination achieved in stages, this element represents the amount of net gain (loss) recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Number 141R

-Paragraph 68

-Name Statement of Financial Accounting Standard (FAS)

-Subparagraph q(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141R

-Paragraph 48

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)(2)

-URI http://asc.fasb.org/extlink&oid=6909870&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGainOrLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Increase for additional borrowings on the debt instrument during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 4

-Section 08

-Paragraph f

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(f))

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

+ Details

Name:	us-gaap_DebtInstrumentIncreaseAdditionalBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Interest rate stated in the contractual debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 159

-Paragraph 18

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 18

-Paragraph 20

-Subparagraph a (1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 323

-SubTopic 10

-Section 50

-Paragraph 3

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Acquisitions (Details) (USD $) In Millions, unless otherwise specified			3 Months Ended		1 Months Ended				12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Jun. 30, 2011 7.76% notes, due 2012 thru 2016	Dec. 31, 2011 7.76% notes, due 2012 thru 2016	May 31, 2011 Appalachian Natural Gas Trust	May 04, 2011 Appalachian Natural Gas Trust	Dec. 31, 2000 Appalachian Natural Gas Trust	May 31, 2011 Appalachian Natural Gas Trust Class A interest	Dec. 31, 2010 Marcellus well mile acre
Acquisitions
Proceeds from sale of net profits interest (NPI) in certain producing properties							$ 298
Percentage of net profits received by ANGT							100.00%
Ownership percentage		100.00%						100.00%
Debt instrument, stated interest rate percentage				7.76%
Aggregate principal amount			57.1
Fair value of notes	3,000.0	2,000.0		64.2
Pre-tax gain on revaluation of existing equity investment in acquiree					10.1
Derecognition of post revaluation of oil and gas properties						140.6
Derecognition of post revaluation of equity investment in ANGT						48.0
Net increase in liabilities						92.6
Liability for discounted sales						16.4
Recognition of a derivative liability for swap						12.7
Approximate area of acquisition (in acres)									58,000
Length of gathering system (in miles)									200
Number of wells acquired									100
Purchase price of acquisition									282.2
Payment for acquisition, in stock									230.7
Payment for acquisition, in cash									$ 51.5