Discontinued Operations - Income Statement Impact of Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NGL sales	$ 19.1	$ 63.2
Other revenue	4.4	2.5
Purchased gas and oil sales	167.3	240.6
Total Revenues	491.6	817.5
Purchased gas and oil expense	169.4	237.9
Lease operating expense	61.8	56.4
Natural gas, oil and NGL transportation and other handling costs	65.1	59.9
Gathering, processing and other	1.7	1.6
General and administrative	47.4	45.3
Production and property taxes	27.8	47.9
Depreciation, depletion and amortization	195.4	225.9
Total operating expenses	589.7	679.1
OPERATING INCOME	(128.6)	140.8
Income from unconsolidated affiliates	0	2.2
Interest expense	(36.8)	(41.9)
Net income attributable to noncontrolling interest	0	(5.8)
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX	0	27.0
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NGL sales		38.0
Other revenue		41.9
Purchased gas and oil sales		(13.4)	[1]
Total Revenues		66.5
Purchased gas and oil expense		(13.8)	[1]
Lease operating expense		(1.1)	[1]
Natural gas, oil and NGL transportation and other handling costs		(16.4)	[1]
Gathering, processing and other		24.3
General and administrative		11.3
Production and property taxes		1.5
Depreciation, depletion and amortization		14.3
Total operating expenses		20.1
OPERATING INCOME		46.4
Income from unconsolidated affiliates		2.2
Interest expense		(0.6)
INCOME FROM DISCONTINUED OPERATIONS BEFORE INCOME TAXES		48.0	[2]
Income taxes		(15.2)
NET INCOME FROM DISCONTINUED OPERATIONS		32.8
Net income attributable to noncontrolling interest		(5.8)
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX		27.0
Income from discontinued operations before income taxes attributable to QEP from QEP Midstream		$ 6.8
Ownership percentage		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 $6.8 million for the three months ended March 31, 2014