Discontinued Operations Income Statement Impact Of Discontinued Operations (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
NGL sales									$ 223.3		$ 192.2		$ 184.2
Other revenues									11.1		22.4		27.5
Purchased gas, oil and NGL sales									1,035.0		774.9		660.0
Total Revenues	799.6	910.0	887.2	817.5	620.3	719.5	694.0	651.3	3,414.3		2,685.1		2,071.7
Purchased gas, oil and NGL expense									1,031.2		783.5		670.7
Lease operating expense									240.1		181.3		175.8
Natural gas, oil and NGL transportation and other handling costs									277.6		222.0		198.1
Gathering and other expense									6.7		8.4		8.2
General and administrative									204.4		160.4		248.4
Production and property taxes									205.2		161.3		98.5
Depreciation, depletion and amortization									994.7		963.8		850.2
Total Operating Expenses									4,113.0		2,585.6		2,394.1
Net gain (loss) from asset sales									(148.6)		103.5		1.2
OPERATING INCOME (LOSS)	(1,067.3)	115.1	(35.9)	140.8	(66.7)	83.3	159.1	27.3	(847.3)		203.0		(321.2)
Realized and unrealized gains (losses) on derivative contracts									363.3		58.9		433.5
Interest and other income									12.8		15.2		15.0
Income from unconsolidated affiliates									0.3		0.2		0.1
Loss from early extinguishment of debt									2.0		0		0.6
Interest expense									(169.1)		(165.1)		(126.3)
Net income attributable to noncontrolling interest									21.6		12.0		3.7
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX	1,135.7	17.4	13.8	27.0	32.4	25.2	29.2	20.5	1,193.9		107.3		125.9
Income from discontinued operations before income taxes attributable to QEP from QEP Midstream									28.9		33.5		38.9
Ownership Percentage	57.80%								57.80%
Midstream Business Held For Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments to Acquire Oil and Gas Property and Equipment									55.2		88.9		156.2
NGL sales									109.3		101.9		137.9
Other revenues									140.9		166.6		154.1
Purchased gas, oil and NGL sales									(47.1)	[1]	(17.8)	[1]	(13.9)	[1]
Total Revenues									203.1		250.7		278.1
Purchased gas, oil and NGL expense									(48.5)	[1]	(17.6)	[1]	(15.1)	[1]
Lease operating expense									(5.5)	[1]	(3.5)	[1]	(3.5)	[1]
Natural gas, oil and NGL transportation and other handling costs									(55.4)	[1]	(80.6)	[1]	(49.2)	[1]
Gathering and other expense									85.9		82.2		79.8
General and administrative									42.1		30.7		17.9
Production and property taxes									7.3		5.2		5.1
Depreciation, depletion and amortization									45.9		52.2		55.1
Total Operating Expenses									71.8		68.6		90.1
Net gain (loss) from asset sales									1,793.4		(0.5)		0
OPERATING INCOME (LOSS)									1,924.7		181.6		188.0
Realized and unrealized gains (losses) on derivative contracts									0		0		8.4
Interest and other income									0.3		(10.0)		(8.2)
Income from unconsolidated affiliates									4.9		5.6		6.7
Loss from early extinguishment of debt									(2.4)		0		0
Interest expense									(3.8)		1.8		3.4
INCOME FROM DISCONTINUED OPERATIONS BEFORE INCOME TAXES									1,923.7	[2]	179.0	[2]	198.3	[2]
Income taxes									(708.2)		(59.7)		(68.7)
NET INCOME FROM DISCONTINUED OPERATIONS									1,215.5		119.3		129.6
Net income attributable to noncontrolling interest									(21.6)		(12.0)		(3.7)
NET INCOME FROM DISCONTINUED OPERATIONS, NET OF INCOME TAX									$ 1,193.9		$ 107.3		$ 125.9

[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 $28.9 million, $33.5 million and $38.9 million for the years ended December 31, 2014, 2013 and 2012, respectively.