CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 156.0		$ 73.8
Other comprehensive income (loss), net of tax:
Reclassification of previously deferred derivative gains and losses to net income	(47.0)	[1]	(47.8)	[1]
Pension and other postretirement plans adjustments:
Amortization of net actuarial loss	0.1	[2]	0
Amortization of prior service cost	0.9	[3]	0
Total pension and other postretirement plans adjustments	1.0		0
Other comprehensive income	(46.0)		(47.8)
Comprehensive income	110.0		26.0
Comprehensive income attributable to noncontrolling interests	(0.8)		(0.6)
Comprehensive income attributable to QEP	109.2		25.4
Income tax benefit of reclassification of derivative gains and losses	27.8		28.3
Income tax expense of amortization of net actuarial loss	0.1
Income tax expense of amortization of prior service cost	$ 0.5

[1] Presented net of income tax benefit of $27.8 million and $28.3 million during the three months ended March 31, 2012 and 2011, respectively.

[2] Presented net of income tax expense of $0.1 million during the three months ended March 31, 2012.

[3] Presented net of income tax expense of $0.5 million during the three months ended March 31, 2012.