Operations by Line of Business (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 603.2	[1],[2]	$ 617.9	[1]
Revenues from affiliated companies	158.4		156.4
Operating (loss) income	49.5	[3]	137.1	[3]
Net income attributable to QEP	155.2		73.2
QEP Energy [Member]
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	396.8	[1],[2]	396.2	[1],[2]
Operating (loss) income	(12.9)	[3]	87.9	[3]
Net income attributable to QEP	108.1		43.1
QEP Field Services [Member]
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	93.6	[1],[2]	73.3	[1],[2]
Revenues from affiliated companies	26.1		23.3
Operating (loss) income	66.0	[3]	47.3	[3]
Net income attributable to QEP	45.4		28.0
QEP Marketing and Other [Member]
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	112.8	[1],[2]	148.4	[1],[2]
Revenues from affiliated companies	132.3		133.1
Operating (loss) income	(3.6)	[3]	1.9	[3]
Net income attributable to QEP	$ 1.7		$ 2.1

[1] Operating (loss) income in the first quarter of 2012 excludes the impact of realized commodity derivative contract settlements. During the first quarter of 2012 realized gains and losses from realized commodity derivative contract settlements were included below operating income. Conversely, under hedge accounting, realized gains and losses from realized commodity derivative contract settlements were included in revenues and operating income during the first quarter of 2011.

[2] Revenues for the three months ended March 31, 2011 have been recast to reflect QEP's revised reporting of its transportation and handling costs. See Note 2 "Basis of Presentation of Interim Consolidated Financial Statements" for additional information. In addition, revenues for the three months ended March 31, 2011 reflect the impact of QEP's settled derivative contracts which during the three months ended March 31, 2012 are reflected below operating income. See Note 7 "Derivative Contracts" for detailed information on derivative contract settlements in the first quarter of 2011.

[3] Net income attributable to QEP in the first quarter of 2012 includes the impact of unrealized gains and losses from changes in the fair value of the commodity derivative contract. Conversely, under hedge accounting, unrealized gains and losses from changes in the fair value were deferred in accumulated other comprehensive income during the first quarter of 2011.