Operations by Line of Business (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total Revenues	$ 468.3	$ 507.6	$ 574.6	$ 468.1	$ 757.1	$ 858.5	$ 850.0	$ 827.6	$ 2,018.6	$ 3,293.2	$ 2,685.1
OPERATING EXPENSES
Purchased gas, oil and NGL expense									(626.8)	(910.1)	(783.5)
Lease operating expense									238.8	240.1	181.3
Natural gas, oil and NGL transportation and other handling costs									291.3	277.6	222.0
Gathering and other expense									5.8	6.7	8.4
General and administrative									181.1	204.4	160.4
Production and property taxes									117.6	205.2	161.3
Depreciation, depletion and amortization									881.1	994.7	963.8
Other Expenses									58.3	1,153.1	104.9
Operating Expenses									2,400.8	3,991.9	2,585.6
Net gain (loss) from asset sales									4.6	(148.6)	103.5
OPERATING INCOME (LOSS)	(144.6)	(87.7)	(16.7)	(128.6)	(1,067.3)	115.1	(35.9)	140.8	(377.6)	(847.3)	203.0
Realized and unrealized gains (losses) on derivative contracts									277.2	363.3	58.9
Gain (Loss) on Derivative Instruments, Net, Pretax									277.2	363.3	58.9
Interest and other income									3.0	12.8	15.2
Income from unconsolidated affiliates									0.0	0.3	0.2
Loss from early extinguishment of debt									0.0	(2.0)	0.0
Interest expense									(145.6)	(169.1)	(165.1)
Income (loss) from continuing operations before income taxes									(243.0)	(642.0)	112.2
Income tax (provision) benefit									93.6	232.5	(60.1)
NET INCOME FROM CONTINUING OPERATIONS					(469.8)	153.7	(106.1)	12.7	(149.4)	(409.5)	52.1
Net income from discontinued operations, net of income tax					1,135.7	17.4	13.8	27.0	0.0	1,193.9	107.3
NET INCOME (LOSS)	(38.6)	21.1	(76.3)	(55.6)	665.9	171.1	(92.3)	39.7	(149.4)	784.4	159.4
Assets	8,425.5				9,286.8				8,425.5	9,286.8	9,408.9
Cash capital expenditures									1,239.4	2,726.4	1,602.6
Accrued capital expenditures									1,110.2	2,734.8	1,577.4
Unaffiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									2,018.6	3,293.2	2,685.1
Affiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									0.0	0.0	0.0
QEP Energy [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,477.2	2,524.6	2,092.8
OPERATING EXPENSES
Purchased gas, oil and NGL expense									(87.3)	(150.0)	(197.1)
Lease operating expense									238.8	240.1	181.3
Natural gas, oil and NGL transportation and other handling costs									300.2	291.5	242.2
Gathering and other expense									0.0	0.0	0.0
General and administrative									176.8	201.3	160.6
Production and property taxes									115.1	204.0	159.8
Depreciation, depletion and amortization									870.8	984.4	954.2
Other Expenses									58.3	1,153.1	104.9
Operating Expenses									1,847.3	3,224.4	2,000.1
Net gain (loss) from asset sales									9.7	(148.6)	104.1
OPERATING INCOME (LOSS)									(360.4)	(848.4)	196.8
Gain (Loss) on Derivative Instruments, Net, Pretax									274.2	367.2	59.1
Interest and other income									1.9	11.8	3.6
Income from unconsolidated affiliates										0.3	0.2
Loss from early extinguishment of debt										0.0
Interest expense									(204.5)	(210.3)	(192.6)
Income (loss) from continuing operations before income taxes									(288.8)	(679.4)	67.1
Income tax (provision) benefit									105.9	246.9	(41.5)
NET INCOME FROM CONTINUING OPERATIONS									(182.9)	(432.5)	25.6
Net income from discontinued operations, net of income tax										0.0	0.0
NET INCOME (LOSS)										(432.5)	25.6
Assets	7,799.5				8,001.1				7,799.5	8,001.1	7,937.0
Cash capital expenditures									1,233.3	2,660.3	1,488.6
Accrued capital expenditures									1,105.7	2,670.5	1,467.2
QEP Energy [Member] | Unaffiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,477.2	2,524.6	2,092.8
QEP Energy [Member] | Affiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									0.0	0.0	0.0
QEP Marketing and Other [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,601.3	2,382.3	1,601.2
OPERATING EXPENSES
Purchased gas, oil and NGL expense									(1,588.1)	(2,356.6)	(1,570.5)
Lease operating expense									0.0	0.0	0.0
Natural gas, oil and NGL transportation and other handling costs									0.0	0.0	0.0
Gathering and other expense									5.8	6.8	8.4
General and administrative									6.7	6.3	4.4
Production and property taxes									2.5	1.2	1.5
Depreciation, depletion and amortization									10.3	10.3	9.6
Other Expenses									0.0	0.0	0.0
Operating Expenses									1,613.4	2,381.2	1,594.4
Net gain (loss) from asset sales									(5.1)	0.0	(0.6)
OPERATING INCOME (LOSS)									(17.2)	1.1	6.2
Gain (Loss) on Derivative Instruments, Net, Pretax									3.0	(3.9)	0.2
Interest and other income									205.7	209.7	206.9
Income from unconsolidated affiliates										0.0	0.0
Loss from early extinguishment of debt										(2.0)
Interest expense									(145.7)	(167.5)	(167.8)
Income (loss) from continuing operations before income taxes									45.8	37.4	45.1
Income tax (provision) benefit									(12.3)	(14.4)	(18.6)
NET INCOME FROM CONTINUING OPERATIONS									33.5	23.0	26.5
Net income from discontinued operations, net of income tax										0.0	0.0
NET INCOME (LOSS)										23.0	26.5
Assets	626.0				1,285.7				626.0	1,285.7	182.2
Cash capital expenditures									6.1	10.9	25.1
Accrued capital expenditures									4.5	13.6	24.6
QEP Marketing and Other [Member] | Unaffiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									654.5	889.7	592.3
QEP Marketing and Other [Member] | Affiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									946.8	1,492.6	1,008.9
Elimination [Member]
Segment Reporting Information [Line Items]
Total Revenues									(1,059.9)	(1,613.7)	(1,008.9)
OPERATING EXPENSES
Purchased gas, oil and NGL expense									1,048.6	1,596.5	984.1
Lease operating expense									0.0	0.0	0.0
Natural gas, oil and NGL transportation and other handling costs									(8.9)	(13.9)	(20.2)
Gathering and other expense									0.0	(0.1)	0.0
General and administrative									(2.4)	(3.2)	(4.6)
Production and property taxes									0.0	0.0	0.0
Depreciation, depletion and amortization									0.0	0.0	0.0
Other Expenses									0.0	0.0	0.0
Operating Expenses									(1,059.9)	(1,613.7)	(1,008.9)
Net gain (loss) from asset sales									0.0	0.0	0.0
OPERATING INCOME (LOSS)									0.0	0.0	0.0
Gain (Loss) on Derivative Instruments, Net, Pretax									0.0	0.0	0.0
Interest and other income									(204.6)	(208.7)	(195.3)
Income from unconsolidated affiliates										0.0	0.0
Loss from early extinguishment of debt										0.0
Interest expense									204.6	208.7	195.3
Income (loss) from continuing operations before income taxes									0.0	0.0	0.0
Income tax (provision) benefit									0.0	0.0	0.0
NET INCOME FROM CONTINUING OPERATIONS									0.0	0.0	0.0
Net income from discontinued operations, net of income tax										0.0	0.0
NET INCOME (LOSS)										0.0	0.0
Assets	$ 0.0				0.0				0.0	0.0	0.0
Cash capital expenditures									0.0	0.0	0.0
Accrued capital expenditures									0.0	0.0	0.0
Elimination [Member] | Unaffiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									(113.1)	(121.1)	0.0
Elimination [Member] | Affiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues									$ (946.8)	(1,492.6)	(1,008.9)
Discontinued Operations [Member]
Segment Reporting Information [Line Items]
Total Revenues										0.0	0.0
OPERATING EXPENSES
Purchased gas, oil and NGL expense										0.0	0.0
Lease operating expense										0.0	0.0
Natural gas, oil and NGL transportation and other handling costs										0.0	0.0
Gathering and other expense										0.0	0.0
General and administrative										0.0	0.0
Production and property taxes										0.0	0.0
Depreciation, depletion and amortization										0.0	0.0
Other Expenses										0.0	0.0
Operating Expenses										0.0	0.0
Net gain (loss) from asset sales										0.0	0.0
OPERATING INCOME (LOSS)										0.0	0.0
Gain (Loss) on Derivative Instruments, Net, Pretax										0.0	0.0
Interest and other income										0.0	0.0
Income from unconsolidated affiliates										0.0	0.0
Loss from early extinguishment of debt										0.0
Interest expense										0.0	0.0
Income (loss) from continuing operations before income taxes										$ 0.0	0.0
Income tax (provision) benefit											0.0
NET INCOME FROM CONTINUING OPERATIONS										$ 0.0	0.0
Net income from discontinued operations, net of income tax										1,193.9	107.3
NET INCOME (LOSS)										1,193.9	107.3
Assets					0.0					0.0	1,289.7
Cash capital expenditures										55.2	88.9
Accrued capital expenditures										50.7	$ 85.6
Eliminations as Reported [Member]
OPERATING EXPENSES
Purchased gas, oil and NGL expense										(1,475.4)
Eliminations as Reported [Member] | Affiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues										0.0
Eliminations as Revised [Member]
OPERATING EXPENSES
Purchased gas, oil and NGL expense										(1,596.5)
Eliminations as Revised [Member] | Unaffiliated customers [Member]
Segment Reporting Information [Line Items]
Total Revenues										(121.1)
Eliminations as Revised [Member] | Change [Member]
Segment Reporting Information [Line Items]
Total Revenues										(121.1)
Change [Member]
Segment Reporting Information [Line Items]
Total Revenues		$ 29.1	$ 34.0	$ 23.5	$ 42.5	$ 51.5	$ 37.2	$ (10.1)
OPERATING EXPENSES
Purchased gas, oil and NGL expense										(121.1)
Operating Expenses										$ 121.1