CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income attributable to QEP	$ 171.1		$ 37.3		$ 118.5		$ 211.4
Other comprehensive (loss) income, net of tax:
Reclassification of previously deferred derivative gains(1)	0	[1]	(19.7)	[1]	0	[1]	(60.4)	[1]
Pension and other postretirement plans adjustments:
Amortization of net actuarial loss	0.2	[2]	0.4	[2]	0.4	[2]	1.1	[2]
Amortization of prior service cost	0.7	[3]	0.8	[3]	2.4	[3]	2.5	[3]
Total pension and other postretirement plans adjustments	0.9		1.2		2.8		3.6
Other comprehensive loss	0.9		(18.5)		2.8		(56.8)
Comprehensive (loss) income attributable to QEP	$ 172.0		$ 18.8		$ 121.3		$ 154.6

[1] Presented net of income tax benefit of $11.7 million and $35.8 million during the three and nine months ended September 30, 2013

[2] Presented net of income tax expense of $0.2 million during the nine months ended September 30, 2014 and $0.2 million and $0.7 million during the three and nine months ended September 30, 2013, respectively.

[3] Presented net of income tax expense of $0.5 million and $1.5 million during the three and nine months ended September 30, 2014, respectively, and $0.5 million and $1.5 million during the three and nine months ended September 30, 2013, respectively.