Discontinued Operations Income Statement Impact of Discontinued Operations (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NGL sales		$ 16.5	$ 51.1	$ 61.7	$ 179.3
Other revenue		2.8	3.4	12.4	5.1
Purchased gas and oil sales		176.3	290.4	558.6	780.1
Total Revenues		536.7	910.0	1,636.9	2,614.7
Purchased gas and oil expense		175.1	288.4	561.7	775.5
Lease operating expense		56.7	61.1	175.6	177.0
Natural gas, oil and NGL transportation and other handling costs		78.1	71.1	216.2	198.5
Gathering, processing and other		1.3	1.4	4.4	4.8
General and administrative		42.0	49.4	140.7	147.0
Production and property taxes		30.2	59.4	90.7	160.8
Depreciation, depletion and amortization		238.1	251.4	649.3	712.5
Total operating expenses		637.3	783.1	1,876.8	2,184.4
Gain (Loss) on Disposition of Property Plant Equipment		12.9	(11.8)	6.9	(210.3)
OPERATING INCOME		(87.7)	115.1	(233.0)	220.0
Income from unconsolidated affiliates				0.0	4.6
Interest expense		(36.4)	(41.5)	(109.4)	(128.4)
Net income attributable to noncontrolling interest				0.0	(17.6)
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX		$ 0.0	17.4	$ 0.0	58.2
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NGL sales			28.8		94.6
Other revenue			43.1		119.9
Purchased gas and oil sales	[1]		(11.9)		(38.5)
Total Revenues			60.0		176.0
Purchased gas and oil expense	[1]		(12.4)		(39.5)
Lease operating expense	[1]		(1.7)		(4.8)
Natural gas, oil and NGL transportation and other handling costs	[1]		(10.6)		(40.1)
Gathering, processing and other			22.7		69.8
General and administrative			11.1		34.3
Production and property taxes			2.1		6.1
Depreciation, depletion and amortization			14.3		43.1
Total operating expenses			25.5		68.9
Gain (Loss) on Disposition of Property Plant Equipment			0.0		(0.1)
OPERATING INCOME			34.5		107.0
Income from unconsolidated affiliates			1.1		4.4
Interest expense			(1.5)		(2.8)
INCOME FROM DISCONTINUED OPERATIONS BEFORE INCOME TAXES	[2]		34.1		108.6
Income taxes			(9.9)		(32.8)
NET INCOME FROM DISCONTINUED OPERATIONS			24.2		75.8
Net income attributable to noncontrolling interest			(6.8)		(17.6)
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX			17.4		58.2
Income from discontinued operations before income taxes attributable to QEP from QEP Midstream			$ 7.9		$ 20.4
Ownership percentage			57.80%		57.80%

[1] Includes discontinued intercompany eliminations

[2] Includes income from discontinued operations before income taxes attributable to QEP from QEP Midstream (of which QEP owned 57.8%) of $7.9 million and $20.4 million for the three and nine months ended September 30, 2014