CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 0.2		$ 93.5		$ 156.2		$ 167.3
Other comprehensive (loss) income, net of tax:
Reclassification of previously deferred derivative gains(1)	(44.7)	[1]	(2.5)	[1]	(91.7)	[1]	(50.3)	[1]
Pension and other postretirement plans adjustments:
Amortization of net actuarial loss	0.1	[2]	0	[2]	0.2	[2]	0	[2]
Amortization of prior service cost	0.8	[3]	1.7	[3]	1.7	[3]	1.7	[3]
Total pension and other postretirement plans adjustments	0.9		1.7		1.9		1.7
Other comprehensive loss	(43.8)		(0.8)		(89.8)		(48.6)
Comprehensive (loss) income	(43.6)		92.7		66.4		118.7
Comprehensive income attributable to noncontrolling interests	(0.9)		(0.7)		(1.7)		(1.3)
Comprehensive (loss) income attributable to QEP	$ (44.5)		$ 92.0		$ 64.7		$ 117.4

[1] Presented net of income tax benefit of $26.5 million and $54.3 million during the three and six months ended June 30, 2012, respectively, and net of income tax benefit of $1.5 million and $29.8 million during the three and six months ended June 30, 2011, respectively.

[2] Presented net of income tax expense of $0.1 million and $0.2 million during the three and six months ended June 30, 2012, respectively,.

[3] Presented net of income tax expense of $0.5 million and $1.1 million during the three and six months ended June 30, 2012, respectively, and net of income tax expense of $1.1 million during the three and six months ended June 30, 2011, respectively.