Fair Value Measurements (Details 2) (USD $)			9 Months Ended
Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2011 Derivative instruments, at fair value, net
Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation
Balance at the beginning of the year			$ 116,672,000
Total gains or losses included in earnings			14,000
Total gains or losses included in other comprehensive income			35,121,000
Settlement			(38,723,000)
Balance at the end of the year			113,084,000
Earnings attributable to the change in unrealized gains/losses			0
Estimated fair value of long-term debt	$ 2,000,000,000	$ 2,000,000,000

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This item represents the total amount of change in unrealized (holding) gains or losses for the period which are included in the statement of income in operating revenues. Such unrealized (holding) gains or losses relate to those assets and liabilities which are still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3).

+ Details

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

- Definition

This element represents the purchases, sales, issuances, and settlements (net) which have taken place during the period, in relation to net assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3).

+ Details

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

- Definition

This element represents the net assets and liabilities measured at fair value using significant unobservable inputs (Level 3) which are required for reconciliation purposes of beginning and ending balances.

+ Details

Name:	eqt_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisNetValue
Namespace Prefix:	eqt
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

This item represents the amount of the total realized and unrealized gains or losses for the period which are included in the statement of income (or changes in net assets); the fair value of which assets and liabilities was or is measured on a recurring basis using significant unobservable inputs (Level 3).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

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

- Definition

This element represents total gains (losses) for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which are included in other comprehensive income (a separate component of shareholders' equity).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-SubTopic 10

-Topic 820

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

+ Details

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- 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.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant