CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Millions, unless otherwise specified	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]
Balance at Dec. 31, 2011	$ 3,352.1	$ 1.8	$ (13.1)	$ 431.4	$ 2,673.5	$ 207.9	$ 50.6
Treasury Stock, Shares at Dec. 31, 2011			(0.4)
Shares, Issued at Dec. 31, 2011		177.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to QEP	128.3				128.3		3.7
Total net income including portion attributable to noncontrolling interest	132.0
Dividends	(14.2)				(14.2)
Equity-based compensation	23.2	0	7.1	30.7	(14.6)
Equity-based compensation, shares issued		1.3
Equity-based compensation, treasury shares reissued			0.2
Distribution to QEP Education Foundation	2.3		2.3
Distribution of noncontrolling interest	(6.6)						(6.6)
Net proceeds from QEP Midstream initial public offering	0
Distribution to QEP Education Foundation, treasury shares reissued			0.1
Reclassification of previously deferred derivative gains in OCI, net of tax	(171.1)					(171.1)
Change in pension and postretirement liability, net of tax	(4.0)					(4.0)
Balance at Dec. 31, 2012	3,313.7	1.8	(3.7)	462.1	2,773.0	32.8	47.7
Shares, Issued at Dec. 31, 2012		178.5
Treasury Stock, Shares at Dec. 31, 2012			(0.1)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to QEP	159.4				159.4		12.0
Total net income including portion attributable to noncontrolling interest	171.4
Dividends	(14.3)				(14.3)
Equity-based compensation	25.0	0	(11.2)	36.3	(0.3)		0.2
Equity-based compensation, shares issued		1.2
Equity-based compensation, treasury shares reissued			(0.3)
Distribution of noncontrolling interest	(9.3)						(9.3)
Net proceeds from QEP Midstream initial public offering	449.6						449.6
Reclassification of previously deferred derivative gains in OCI, net of tax	(77.6)					(77.6)
Change in pension and postretirement liability, net of tax	18.3					18.3
Balance at Dec. 31, 2013	3,876.8	1.8	(14.9)	498.4	2,917.8	(26.5)	500.2
Shares, Issued at Dec. 31, 2013		179.7
Treasury Stock, Shares at Dec. 31, 2013	(0.4)		(0.4)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income attributable to QEP	784.4				784.4		0
Total net income including portion attributable to noncontrolling interest	784.4
Dividends	(14.6)				(14.6)
Equity-based compensation	26.6	0	(10.5)	36.9	0		0.2
Equity-based compensation, shares issued		1.2
Equity-based compensation, treasury shares reissued			(0.4)
Distribution of noncontrolling interest	(31.9)						(31.9)
Net proceeds from QEP Midstream initial public offering	0
Reclassification of previously deferred derivative gains in OCI, net of tax						0
Common stock repurchased and retired	(99.7)				(99.7)
Common stock repurchased and retired, shares		(4.7)
Change in pension and postretirement liability, net of tax	2.2					2.2
Noncontrolling interest decrease from Midstream Sale	(468.5)						(468.5)
Balance at Dec. 31, 2014	$ 4,075.3	$ 1.8	$ (25.4)	$ 535.3	$ 3,587.9	$ (24.3)	$ 0
Shares, Issued at Dec. 31, 2014		176.2
Treasury Stock, Shares at Dec. 31, 2014	(0.8)		(0.8)