Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

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The contract year for the derivative contract.

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No definition available.

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The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

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Gain included in earnings for the period from the change in fair value of derivative instruments not designated as hedging instruments.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

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Loss included in earnings for the period from the change in fair value of derivative instruments not designated as hedging instruments.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

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The price per unit of the notional amount of the derivative contract expressed in nonmonetary units. For example, the price per barrel specified in a fuel oil forward purchase contract.

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Reference to the index or unit of measurement for the underlying which establishes the pricing terms of the derivative instrument. For example, the basis on the underlying for a natural gas futures contract might be the NYMEX price per million British thermal units (MMBtu).

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Derivative Contracts (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Effect of derivative instruments designated as cash flow hedges [Abstract]
Gains (losses) recognized in AOCI for the effective portion of hedges	$ 350.8	$ 565.8	$ 214.4
Effect of derivative instruments not designated as hedges [Abstract]
Unrealized gain on basis-only swaps	117.7	121.7	(164.0)
Realized loss on basis-only swaps	(117.7)	(121.7)	(25.6)
Amount that will be settled and reclassified from AOCI to the Consolidated Statements of Income during the next twelve months	171.1
Short-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	284.1	412.5
Fair value of derivative liabilities, gross	11.7	294.5
Long-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	123.5	121.1
Fair value of derivative liabilities, gross	0	0.6
Costless Collars [Member] \| Short-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	0	37.9
Fair value of derivative liabilities, gross	0	1.6
Costless Collars [Member] \| Long-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	0	0
Fair value of derivative liabilities, gross	0	0
Basis-only swaps [Member] \| Short-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative liabilities, gross	0	117.7
Basis-only swaps [Member] \| Long-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative liabilities, gross	0	0
Fixed-price swaps [Member] \| Short-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	284.1	374.6
Fair value of derivative liabilities, gross	11.7	175.2
Fixed-price swaps [Member] \| Long-term [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Fair value of derivative assets, gross	123.5	121.1
Fair value of derivative liabilities, gross	0	0.6
Natural Gas Sales (MMbtu) [Member]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges [Abstract]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges	305.5	353.8	599.3
Natural Gas Sales (MMbtu) [Member] \| Swap [Member] \| 2012 [Member] \| IFNPCR [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFNPCR
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	62.2
Average Swap price per unit ($ per unit)	5.50
Derivative - Contract Year	2012
Natural Gas Sales (MMbtu) [Member] \| Swap [Member] \| 2012 [Member] \| IFPEPL [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFPEPL
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	7.3
Average Swap price per unit ($ per unit)	4.70
Derivative - Contract Year	2012
Natural Gas Sales (MMbtu) [Member] \| Swap [Member] \| 2012 [Member] \| NYMEX [Member]
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	69.5
Natural Gas Sales (MMbtu) [Member] \| Swap [Member] \| 2013 [Member] \| IFNPCR [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFNPCR
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	65.7
Average Swap price per unit ($ per unit)	5.66
Derivative - Contract Year	2013
Natural Gas Sales (MMbtu) [Member] \| Swap [Member] \| 2013 [Member] \| NYMEX [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	NYMEX
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	3.7
Average Swap price per unit ($ per unit)	4.65
Derivative - Contract Year	2013
Oil Sales (Bbls) [Member]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges [Abstract]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges	1.6	(8.7)	1.6
Oil Sales (Bbls) [Member] \| Swap [Member] \| 2012 [Member] \| NYMEX WTI [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	NYMEX WTI
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	1.8
Average Swap price per unit ($ per unit)	97.03
Derivative - Contract Year	2012
Oil Sales (Bbls) [Member] \| Swap [Member] \| 2013 [Member] \| NYMEX WTI [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	NYMEX WTI
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	0.2
Average Swap price per unit ($ per unit)	105.80
Derivative - Contract Year	2013
Gathering, Processing and Other [Member]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges [Abstract]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges	(0.2)	0	0
Purchased Gas and Oil Sales [Member]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges [Abstract]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges	0	0	27.8
Purchased Gas and Oil Expense [Member]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges [Abstract]
Gains (losses) reclassified from AOCI into income for the effective portion of hedges	4.3	3.1	(9.2)
Interest and Other Income [Member]
Loss recognized in income for the ineffective portion of hedges [Abstract]
Interest and other income	$ 0.1	$ 0.2	$ (0.1)
Propane Sales (Gals) [Member] \| Swap [Member] \| 2012 [Member] \| Mt. Belvieu Propane [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	Mt. Belvieu Propane
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	7.7
Average Swap price per unit ($ per unit)	1.28
Derivative - Contract Year	2012
Gas Purchases (millions of MMBtu) [Member] \| Swap [Member] \| 2012 [Member] \| IFNPCR [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFNPCR
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	0.3
Average Swap price per unit ($ per unit)	3.54
Derivative - Contract Year	2012
Gas (Bcf) [Member] \| Swap [Member] \| 2012 [Member] \| NYMEX [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	NYMEX
Derivative Contracts - Volumes and Prices
Average Swap price per unit ($ per unit)	4.93
Derivative - Contract Year	2012
QEP Marketing [Member] \| Swap [Member] \| 2012 [Member] \| IFNPCR [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFNPCR
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	3.3
Average Swap price per unit ($ per unit)	4.41
Derivative - Contract Year	2012
QEP Marketing [Member] \| Swap [Member] \| 2013 [Member] \| IFNPCR [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	IFNPCR
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	0.9
Average Swap price per unit ($ per unit)	4.77
Derivative - Contract Year	2013
Ethane Sales (Gals) [Member] \| Swap [Member] \| 2012 [Member] \| Mt. Belvieu Ethane [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	Mt. Belvieu Ethane
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	15.4
Average Swap price per unit ($ per unit)	0.64
Derivative - Contract Year	2012
QEP Field Services [Member] \| Swap [Member] \| 2012 [Member] \| Mt. Belvieu Ethane [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	Mt. Belvieu Ethane
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	15.4
Average Swap price per unit ($ per unit)	0.64
Derivative - Contract Year	2012
QEP Field Services [Member] \| Swap [Member] \| 2012 [Member] \| Mt. Belvieu Propane [Member]
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative, Index	Mt. Belvieu Propane
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)	15.4
Average Swap price per unit ($ per unit)	1.36
Derivative - Contract Year	2012