Derivative Contracts (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																																													3 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 QEP Energy [Member] Natural gas derivative contracts [Member]	Mar. 31, 2011 QEP Energy [Member] Natural gas derivative contracts [Member]	Mar. 31, 2012 QEP Energy [Member] Oil derivative contracts [Member]	Mar. 31, 2011 QEP Energy [Member] Oil derivative contracts [Member]	Mar. 31, 2012 QEP Energy [Member] NGL derivative contracts [Member]	Mar. 31, 2011 QEP Energy [Member] NGL derivative contracts [Member]	Mar. 31, 2012 QEP Field Services [Member] NGL derivative contracts [Member]	Mar. 31, 2011 QEP Field Services [Member] NGL derivative contracts [Member]	Mar. 31, 2012 QEP Marketing [Member] Natural gas derivative contracts [Member]	Mar. 31, 2011 QEP Marketing [Member] Natural gas derivative contracts [Member]	Mar. 31, 2012 Realized and unrealized gains on commodity derivative instruments [Member]	Mar. 31, 2011 Realized and unrealized gains on commodity derivative instruments [Member]	Mar. 31, 2012 Accumulated other comprehensive income (loss) [Member]	Mar. 31, 2011 Accumulated other comprehensive income (loss) [Member]	Mar. 31, 2012 Natural Gas Sales [Member]	Mar. 31, 2011 Natural Gas Sales [Member]	Mar. 31, 2012 Oil Sales [Member]	Mar. 31, 2011 Oil Sales [Member]	Mar. 31, 2012 NGL Sales [Member]	Mar. 31, 2011 NGL Sales [Member]	Mar. 31, 2012 Marketing Purchases [Member]	Mar. 31, 2011 Marketing Purchases [Member]	Mar. 31, 2012 Interest and Other Income [Member]	Mar. 31, 2011 Interest and Other Income [Member]	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2012 [Member] NYMEX [Member] Bcf	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2012 [Member] IFPEPL [Member] MMBTU	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2012 [Member] IFNPCR [Member] MMBTU	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2012 [Member] IFCNPTE [Member] MMBTU	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2013 [Member] NYMEX [Member] Bcf	Mar. 31, 2012 Swap [Member] Natural Gas Sales (MMbtu) [Member] 2013 [Member] IFNPCR [Member] MMBTU	Mar. 31, 2012 Swap [Member] Oil Sales (Bbls) [Member] 2012 [Member] NYMEX WTI [Member] MMBbls	Mar. 31, 2012 Swap [Member] NGL Sales [Member] 2012 [Member] Mt. Belvieu Ethane [Member] gal	Mar. 31, 2012 Swap [Member] NGL Sales [Member] 2012 [Member] Mt. Belvieu Propane [Member] gal	Mar. 31, 2012 Swap [Member] QEP Field Services [Member] 2012 [Member] Mt. Belvieu Ethane [Member] gal	Mar. 31, 2012 Swap [Member] QEP Field Services [Member] 2012 [Member] Mt. Belvieu Propane [Member] gal	Mar. 31, 2012 Swap [Member] QEP Marketing [Member] 2012 [Member] IFNPCR [Member] MMBTU	Mar. 31, 2012 Swap [Member] QEP Marketing [Member] 2013 [Member] IFNPCR [Member] MMBTU	Mar. 31, 2012 Swap [Member] Purchased Gas and Oil Expense [Member] 2012 [Member] IFNPCR [Member] MMBTU	Mar. 31, 2012 Costless Collars [Member]	Dec. 31, 2011 Costless Collars [Member]	Mar. 31, 2012 Costless Collars [Member] Short-term [Member]	Dec. 31, 2011 Costless Collars [Member] Short-term [Member]	Mar. 31, 2012 Costless Collars [Member] Long-term [Member]	Dec. 31, 2011 Costless Collars [Member] Long-term [Member]	Mar. 31, 2012 Costless Collars [Member] Oil Sales (Bbls) [Member] 2012 [Member] NYMEX WTI [Member] MMBbls	Mar. 31, 2012 Costless Collars [Member] Oil Sales (Bbls) [Member] 2013 [Member] NYMEX WTI [Member] MMBbls	Mar. 31, 2012 QEP Energy [Member] Fixed-price swaps [Member] Natural Gas Sales (MMbtu) [Member]	Mar. 31, 2011 QEP Energy [Member] Fixed-price swaps [Member] Natural Gas Sales (MMbtu) [Member]	Mar. 31, 2012 QEP Energy [Member] Fixed-price swaps [Member] Oil Sales (Bbls) [Member]	Mar. 31, 2011 QEP Energy [Member] Fixed-price swaps [Member] Oil Sales (Bbls) [Member]	Mar. 31, 2012 QEP Energy [Member] Fixed-price swaps [Member] NGL Sales [Member]	Mar. 31, 2011 QEP Energy [Member] Fixed-price swaps [Member] NGL Sales [Member]	Mar. 31, 2012 QEP Energy [Member] Costless Collars [Member] Natural Gas Sales (MMbtu) [Member]	Mar. 31, 2011 QEP Energy [Member] Costless Collars [Member] Natural Gas Sales (MMbtu) [Member]	Mar. 31, 2012 QEP Energy [Member] Costless Collars [Member] Oil Sales (Bbls) [Member]	Mar. 31, 2011 QEP Energy [Member] Costless Collars [Member] Oil Sales (Bbls) [Member]	Mar. 31, 2012 QEP Energy [Member] Costless Collars [Member] NGL Sales [Member]	Mar. 31, 2011 QEP Energy [Member] Costless Collars [Member] NGL Sales [Member]	Mar. 31, 2012 QEP Field Services [Member] Fixed-price swaps [Member] Ethane Sales (Gals) [Member]	Mar. 31, 2011 QEP Field Services [Member] Fixed-price swaps [Member] Ethane Sales (Gals) [Member]	Mar. 31, 2012 QEP Field Services [Member] Fixed-price swaps [Member] Propane Sales (Gals) [Member]	Mar. 31, 2011 QEP Field Services [Member] Fixed-price swaps [Member] Propane Sales (Gals) [Member]
Derivative Contracts [Abstract]
Forecasted production from proved reserves (in hundredths)	100.00%
Unrealized gains on derivative contracts	$ 395.9
Unrealized gains on derivative contracts, net of tax	248.6
Derivative [Line Items]
Derivative volumes as a percent of production (in hundredths)																																																60.00%	43.00%	37.00%	0.00%	16.00%	0.00%	0.00%	12.00%	15.00%	35.00%	0.00%	0.00%	32.00%	0.00%	88.00%	0.00%
Derivatives, Fair Value [Line Items]
Derivative, Index																										NYMEX	IFPEPL	IFNPCR	IFCNPTE	NYMEX	IFNPCR	NYMEX WTI	Mt. Belvieu Ethane	Mt. Belvieu Propane	Mt. Belvieu Ethane	Mt. Belvieu Propane	IFNPCR	IFNPCR	IFNPCR							NYMEX WTI	NYMEX WTI
Derivative Contracts - Volumes and Prices
Total Volume (in Bcf, Mbbl, millions of gallons, millions of MMBtu)																										57.8	6.1	65.4	7.7	29.2	65.7	1.4	11.6	17.3	11.6	9.6	1.7	1.2	1.1							1.1	0.2
Average Swap price per unit ($ per unit)																										4.72	4.47	4.69	2.67	3.68	5.66	97.03	0.64	1.28	0.64	1.35	4.15	4.57	2.80								105.80
Collars Floor Price ($ per unit)																																														$ 87.50
Collars Ceiling Price ($ per unit)																																														$ 115
Derivative - Contract Year																										2012	2012	2012	2012	2013	2013	2012	2012	2012	2012	2012	2012	2013	2012							2012	2013
Fair Value of Derivative Contracts, Gross [Abstract]
Derivative Asset, Fair Value, Gross																																								463.3	407.6	347.5	284.1	115.8	123.5
Derivative Liability, Fair Value, Gross																																								14.0	11.7	13.7	11.7	0.3	0
Amount that will be settled and reclassified from AOCI to Consolidated Statement of Income during the next twelve months	144.2
Derivatives not designated as hedging instruments - Commodity derivatives [Abstract]
Realized gain (loss) on commodity derivative contracts		85.7	(31.2)	(2.7)	0	0.4	0	1.1	0	3.5	0	88.0	(31.2)
Unrealized gain (loss) on commodity derivative contracts		132.3	31.2	(11.5)	0	2.9	0	3.0	0	1.6	0	128.3	31.2
Total gain (loss) on commodity derivative instruments												216.3	0
Gain (loss) on derivative instruments for the effective portion of hedge recognized in AOCI [Abstract]
Gain (loss) on derivative instruments for the effective portion of hedge recognized in AOCI														0	0.2	0	73.1	0	0	0	0	0	3.4
Gain (loss) recognized in income for the ineffective portion of hedges [Abstract]
Interest and other income																								$ 0	$ (0.2)