Operations by Line of Business (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
Revenues
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
Operating expenses
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
Other Expenses									1,153.1	104.9	144.2
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)
Income (loss) from continuing operations before income taxes									(642.0)	112.2	0.5
Income tax (provision) benefit									232.5	(60.1)	1.9
NET INCOME FROM CONTINUING OPERATIONS	(469.8)	153.7	(106.1)	12.7	(84.4)	12.1	149.2	(24.8)	(409.5)	52.1	2.4
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
NET INCOME ATTRIBUTABLE TO QEP	665.9	171.1	(92.3)	39.7	(52.0)	37.3	178.4	(4.3)	784.4	159.4	128.3
Assets	9,286.8				9,408.9				9,286.8	9,408.9	9,108.5
Cash capital expenditures									2,726.4	1,602.6	2,799.7
Accrued capital expenditures									2,734.8	1,577.4	2,888.2
Goodwill											59.5
Unaffiliated customers [Member]
Revenues
Total Revenues									3,414.3	2,685.1	2,071.7
Affiliated customers [Member]
Revenues
Total Revenues									0	0	0
QEP Energy [Member]
Revenues
Total Revenues									2,524.6	2,092.8	1,615.4
Operating expenses
Purchased gas, oil and NGL expense									150.0	197.1	224.7
Lease operating expense									240.1	181.3	175.8
Natural gas, oil and NGL transportation and other handling costs									291.5	242.2	228.1
Gathering and other expense									0	0	0
General and administrative									201.3	160.6	252.8
Production and property taxes									204.0	159.8	97.2
Depreciation, depletion and amortization									984.4	954.2	838.4
Other Expenses									1,153.1	104.9	144.2
Operating Expenses									3,224.4	2,000.1	1,961.2
Net gain (loss) from asset sales									(148.6)	104.1	1.2
OPERATING INCOME (LOSS)									(848.4)	196.8	(344.6)
Realized and unrealized gains (losses) on derivative contracts									367.2	59.1	434.9
Interest and other income									11.8	3.6	6.2
Income from unconsolidated affiliates									0.3	0.2	0.1
Loss from early extinguishment of debt											0
Interest expense									(210.3)	(192.6)	(116.8)
Income (loss) from continuing operations before income taxes									(679.4)	67.1	(20.2)
Income tax (provision) benefit									(246.9)	41.5	(12.1)
NET INCOME FROM CONTINUING OPERATIONS									(432.5)	25.6	(8.1)
Net income from discontinued operations, net of income tax									0	0	0
NET INCOME ATTRIBUTABLE TO QEP									(432.5)		(8.1)
Assets	8,001.1				7,937.0				8,001.1	7,937.0	7,436.5
Cash capital expenditures									2,660.3	1,488.6	2,621.1
Accrued capital expenditures									2,670.5	1,467.2	2,702.4
Goodwill											59.5
QEP Energy [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues									2,524.6	2,092.8	1,615.4
QEP Energy [Member] | Affiliated customers [Member]
Revenues
Total Revenues									0	0	0
QEP Marketing and Other [Member]
Revenues
Total Revenues									2,382.3	1,601.2	1,067.5
Operating expenses
Purchased gas, oil and NGL expense									2,356.6	1,570.5	1,021.1
Lease operating expense									0	0	0
Natural gas, oil and NGL transportation and other handling costs									0	0	0
Gathering and other expense									6.8	8.4	8.2
General and administrative									6.3	4.4	1.7
Production and property taxes									1.2	1.5	1.3
Depreciation, depletion and amortization									10.3	9.6	11.8
Other Expenses									0	0	0
Operating Expenses									2,381.2	1,594.4	1,044.1
Net gain (loss) from asset sales									0	(0.6)	0
OPERATING INCOME (LOSS)									1.1	6.2	23.4
Realized and unrealized gains (losses) on derivative contracts									(3.9)	(0.2)	(1.4)
Interest and other income									209.7	206.9	132.3
Income from unconsolidated affiliates									0	0	0
Loss from early extinguishment of debt									(2.0)		(0.6)
Interest expense									(167.5)	(167.8)	(133.0)
Income (loss) from continuing operations before income taxes									37.4	45.1	20.7
Income tax (provision) benefit									14.4	18.6	10.2
NET INCOME FROM CONTINUING OPERATIONS									23.0	26.5	10.5
Net income from discontinued operations, net of income tax									0	0	0
NET INCOME ATTRIBUTABLE TO QEP									23.0		10.5
Assets	1,285.7				182.2				1,285.7	182.2	244.6
Cash capital expenditures									10.9	25.1	22.4
Accrued capital expenditures									13.6	24.6	21.6
Goodwill											0
QEP Marketing and Other [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues									889.7	592.3	456.3
QEP Marketing and Other [Member] | Affiliated customers [Member]
Revenues
Total Revenues									1,492.6	1,008.9	611.2
Elimination [Member]
Revenues
Total Revenues									(1,492.6)	(1,008.9)	(611.2)
Operating expenses
Purchased gas, oil and NGL expense									(1,475.4)	(984.1)	(575.1)
Lease operating expense									0	0	0
Natural gas, oil and NGL transportation and other handling costs									(13.9)	(20.2)	(30.0)
Gathering and other expense									(0.1)	0	0
General and administrative									(3.2)	(4.6)	(6.1)
Production and property taxes									0	0	0
Depreciation, depletion and amortization									0	0
Other Expenses									0	0	0
Operating Expenses									(1,492.6)	(1,008.9)	(611.2)
Net gain (loss) from asset sales									0	0	0
OPERATING INCOME (LOSS)									0	0	0
Realized and unrealized gains (losses) on derivative contracts									0	0	0
Interest and other income									(208.7)	(195.3)	(123.5)
Income from unconsolidated affiliates									0	0	0
Loss from early extinguishment of debt									0		0
Interest expense									208.7	195.3	123.5
Income (loss) from continuing operations before income taxes									0	0	0
Income tax (provision) benefit									0	0	0
NET INCOME FROM CONTINUING OPERATIONS									0	0	0
Net income from discontinued operations, net of income tax									0	0	0
NET INCOME ATTRIBUTABLE TO QEP									0		0
Assets	0				0				0	0	0
Cash capital expenditures									0	0	0
Accrued capital expenditures									0	0	0
Goodwill											0
Elimination [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues									0	0	0
Elimination [Member] | Affiliated customers [Member]
Revenues
Total Revenues									(1,492.6)	(1,008.9)	(611.2)
Discontinued Operations [Member]
Revenues
Total Revenues									0	0	0
Operating expenses
Purchased gas, oil and NGL expense									0	0	0
Lease operating expense									0	0	0
Natural gas, oil and NGL transportation and other handling costs									0	0	0
Gathering and other expense									0	0	0
General and administrative									0	0	0
Production and property taxes									0	0	0
Depreciation, depletion and amortization									0	0	0
Other Expenses									0	0	0
Operating Expenses									0	0	0
Net gain (loss) from asset sales									0	0	0
OPERATING INCOME (LOSS)									0	0	0
Realized and unrealized gains (losses) on derivative contracts									0	0	0
Interest and other income									0	0	0
Income from unconsolidated affiliates									0	0	0
Loss from early extinguishment of debt									0		0
Interest expense									0	0	0
Income (loss) from continuing operations before income taxes									0	0	0
Income tax (provision) benefit									0	0	0
NET INCOME FROM CONTINUING OPERATIONS									0	0	0
Net income from discontinued operations, net of income tax									1,193.9	107.3	125.9
NET INCOME ATTRIBUTABLE TO QEP									1,193.9	107.3	125.9
Assets	0				1,289.7				0	1,289.7	1,427.4
Cash capital expenditures									55.2	88.9	156.2
Accrued capital expenditures									50.7	85.6	164.2
Discontinued Operations [Member] | Affiliated customers [Member]
Revenues
Total Revenues									$ 0