Operations by Line of Business (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	57.80%
Revenues
Total Revenues	$ 883.9	$ 696.5
Operating expenses
Purchased gas, oil and NGL expense	224.3	196.8
Lease operating expense	55.3	40.1
Natural gas, oil and NGL transportation and other handling costs	43.4	32.8
Gathering, processing and other	25.8	20.6
General and administrative	56.6	46.0
Production and property taxes	49.3	35.9
Depreciation, depletion and amortization	240.2	254.2
Other operating expenses	4.2	5.1
Total Operating Expenses	699.1	631.5
Net (loss) gain from asset sales	2.4	(0.2)
Operating (loss) income	187.2	64.8
Realized and unrealized gains (losses) on derivative contracts	(80.9)	(34.6)
Interest and other income	2.9	2.0
Income from unconsolidated affiliates	2.2	1.3
Interest expense	(42.5)	(39.4)
Income (loss) before income taxes	68.9	(5.9)
Income taxes	(23.4)	2.2
Net (loss) income	45.5	(3.7)
Net income attributable to noncontrolling interest	(5.8)	(0.6)
Net income (loss) attributable to QEP	39.7	(4.3)
Assets	10,579.6	9,143.9	9,376.8
Unaffiliated customers [Member]
Revenues
Total Revenues	883.9	696.5
Affiliated customers [Member]
Revenues
Total Revenues	0	0
QEP Energy [Member]
Revenues
Total Revenues	613.2	508.2
Operating expenses
Purchased gas, oil and NGL expense	38.0	65.7
Lease operating expense	56.4	41.0
Natural gas, oil and NGL transportation and other handling costs	64.5	56.2
Gathering, processing and other	0	0
General and administrative	41.8	36.7
Production and property taxes	47.4	34.7
Depreciation, depletion and amortization	223.4	238.1
Other operating expenses	4.2	5.1
Total Operating Expenses	475.7	477.5
Net (loss) gain from asset sales	2.4	0.1
Operating (loss) income	139.9	30.8
Realized and unrealized gains (losses) on derivative contracts	(78.5)	(34.2)
Interest and other income	2.9	1.7
Income from unconsolidated affiliates	0	0
Interest expense	(48.9)	(45.3)
Income (loss) before income taxes	15.4	(47.0)
Income taxes	(5.9)	17.2
Net (loss) income	9.5	(29.8)
Net income attributable to noncontrolling interest	0	0
Net income (loss) attributable to QEP	9.5	(29.8)
Assets	9,004.1	7,756.8
QEP Energy [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues	613.2	508.2
QEP Energy [Member] | Affiliated customers [Member]
Revenues
Total Revenues	0	0
QEP Field Services [Member]
Revenues
Total Revenues	106.2	92.0
Operating expenses
Purchased gas, oil and NGL expense	0	5.1
Lease operating expense	0	0
Natural gas, oil and NGL transportation and other handling costs	3.6	2.8
Gathering, processing and other	25.7	20.3
General and administrative	14.4	9.5
Production and property taxes	1.8	1.1
Depreciation, depletion and amortization	16.5	15.8
Other operating expenses	0	0
Total Operating Expenses	62.0	54.6
Net (loss) gain from asset sales	0	(0.3)
Operating (loss) income	44.2	37.1
Realized and unrealized gains (losses) on derivative contracts	0	0
Interest and other income	0	0.3
Income from unconsolidated affiliates	2.2	1.3
Interest expense	(0.6)	(4.0)
Income (loss) before income taxes	45.8	34.7
Income taxes	(14.6)	(12.5)
Net (loss) income	31.2	22.2
Net income attributable to noncontrolling interest	(5.8)	(0.6)
Net income (loss) attributable to QEP	25.4	21.6
Assets	1,515.5	1,660.6
QEP Field Services [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues	79.8	64.4
QEP Field Services [Member] | Affiliated customers [Member]
Revenues
Total Revenues	26.4	27.6
QEP Marketing and Other [Member]
Revenues
Total Revenues	503.0	341.1
Operating expenses
Purchased gas, oil and NGL expense	497.9	342.5
Lease operating expense	0	0
Natural gas, oil and NGL transportation and other handling costs	0	0
Gathering, processing and other	0.4	0.3
General and administrative	1.2	1.0
Production and property taxes	0.1	0.1
Depreciation, depletion and amortization	0.3	0.3
Other operating expenses	0	0
Total Operating Expenses	499.9	344.2
Net (loss) gain from asset sales	0	0
Operating (loss) income	3.1	(3.1)
Realized and unrealized gains (losses) on derivative contracts	(2.4)	(0.4)
Interest and other income	48.8	51.2
Income from unconsolidated affiliates	0	0
Interest expense	(41.8)	(41.3)
Income (loss) before income taxes	7.7	6.4
Income taxes	(2.9)	(2.5)
Net (loss) income	4.8	3.9
Net income attributable to noncontrolling interest	0	0
Net income (loss) attributable to QEP	4.8	3.9
Assets	314.6	294.9
QEP Marketing and Other [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues	190.9	123.9
QEP Marketing and Other [Member] | Affiliated customers [Member]
Revenues
Total Revenues	312.1	217.2
Elimination [Member]
Revenues
Total Revenues	(338.5)	(244.8)
Operating expenses
Purchased gas, oil and NGL expense	(311.6)	(216.5)
Lease operating expense	(1.1)	(0.9)
Natural gas, oil and NGL transportation and other handling costs	(24.7)	(26.2)
Gathering, processing and other	(0.3)	0
General and administrative	(0.8)	(1.2)
Production and property taxes	0	0
Depreciation, depletion and amortization	0	0
Other operating expenses	0	0
Total Operating Expenses	(338.5)	(244.8)
Net (loss) gain from asset sales		0
Operating (loss) income	0	0
Realized and unrealized gains (losses) on derivative contracts	0	0
Interest and other income	(48.8)	(51.2)
Income from unconsolidated affiliates	0	0
Interest expense	48.8	51.2
Income (loss) before income taxes	0	0
Income taxes	0	0
Net (loss) income	0	0
Net income attributable to noncontrolling interest	0	0
Net income (loss) attributable to QEP	0	0
Assets	(254.6)	(568.4)
Elimination [Member] | Unaffiliated customers [Member]
Revenues
Total Revenues	0	0
Elimination [Member] | Affiliated customers [Member]
Revenues
Total Revenues	$ (338.5)	$ (244.8)