Supplemental Gas and Oil Information (Unaudited) Estimated Quantities of Proved Gas and Oil Reserves (Details) MMcf in Millions, MMBbls in Millions		12 Months Ended
		Dec. 31, 2015 MMcf MMBbls		Dec. 31, 2014 MMcf MMBbls		Dec. 31, 2013 MMcf MMBbls		Dec. 31, 2012 MMcf MMBbls
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance | MMBbls
Proved reserves balance, ending balance | MMBbls
Natural Gas [Member]
Reserve Quantities [Line Items]
Reserves, Unit of Measure				(Bcf)
Proved reserves balance, beginning balance		2,317.2		2,554.9		2,622.4
Extensions and discoveries		(463.8)	[1]	27.1	[2]	(288.3)	[3]
Extensions and discoveries		467.7	[4]	141.4	[5]	455.6	[6]
Purchase of reserves in place		3.2	[7]	72.5	[8]	1.0
Sale of reserves in place		(34.3)	[9]	(299.4)	[10]	(16.9)
Production		(181.1)		(179.3)		(218.9)
Proved reserves balance, ending balance		2,108.9		2,317.2		2,554.9		2,622.4
Proved developed reserves, beginning balance		1,288.4		1,406.3		1,531.7
Proved developed reserves, ending balance		1,245.3		1,288.4		1,406.3		1,531.7
Proved undeveloped reserves, beginning balance		1,028.8		1,148.6		1,090.7
Proved undeveloped reserve, ending balance		863.6		1,028.8		1,148.6		1,090.7
Oil [Member]
Reserve Quantities [Line Items]
Reserves, Unit of Measure				(MMbbl)
Proved reserves balance, beginning balance | MMBbls		172.5		148.6		119.0
Extensions and discoveries | MMBbls		(47.0)	[1]	(4.0)	[2]	1.3	[3]
Extensions and discoveries | MMBbls		85.6	[4]	16.8	[5]	38.3	[6]
Purchase of reserves in place | MMBbls		2.0	[7]	35.7	[8]	1.9
Sale of reserves in place | MMBbls		(0.4)	[9]	(7.5)	[10]	(1.7)
Production | MMBbls		(19.6)		(17.1)		(10.2)
Proved reserves balance, ending balance | MMBbls		193.1		172.5		148.6		119.0
Proved developed reserves, beginning balance | MMBbls		99.3		71.8		47.4
Proved developed reserves, ending balance | MMBbls		109.7		99.3		71.8		47.4
Proved undeveloped reserves, beginning balance | MMBbls		73.2		76.8		71.6
Proved undeveloped reserve, ending balance | MMBbls		83.4		73.2		76.8		71.6
Natural Gas Liquids [Member]
Reserve Quantities [Line Items]
Reserves, Unit of Measure				(MMbbl)
Proved reserves balance, beginning balance | MMBbls		96.6		102.6		99.9
Extensions and discoveries | MMBbls		(55.3)	[1]	1.4	[2]	(8.0)	[3]
Extensions and discoveries | MMBbls		21.8	[4]	8.6	[5]	16.4	[6]
Purchase of reserves in place | MMBbls		0.6	[7]	12.3	[8]	0.2
Sale of reserves in place | MMBbls		(0.2)	[9]	(21.5)	[10]	(1.1)
Production | MMBbls		(4.7)		(6.8)		(4.8)
Proved reserves balance, ending balance | MMBbls		58.8		96.6		102.6		99.9
Proved developed reserves, beginning balance | MMBbls		52.2		52.8		49.3
Proved developed reserves, ending balance | MMBbls		34.4		52.2		52.8		49.3
Proved undeveloped reserves, beginning balance | MMBbls		44.4		49.8		50.6
Proved undeveloped reserve, ending balance | MMBbls		24.4		44.4		49.8		50.6
Total Reserves Natural Gas Equivalent [Member]
Reserve Quantities [Line Items]
Reserves, Unit of Measure				(Bcfe)
Proved reserves balance, beginning balance		3,931.9		4,061.9		3,936.1
Extensions and discoveries		(1,077.9)	[1]	11.3	[2]			(328.5)	[3]
Extensions and discoveries		1,111.9	[4],[6]	294.1	[5]	783.8	[6]
Purchase of reserves in place		18.7	[7]	360.7	[8]			13.4
Sale of reserves in place		(37.6)	[9]	(473.4)	[10]			(33.9)
Production		(326.8)		(322.7)				(309.0)
Proved reserves balance, ending balance		3,620.2		3,931.9		4,061.9		3,936.1
Proved developed reserves, beginning balance		2,197.5		2,154.0		2,111.9
Proved developed reserves, ending balance		2,109.4		2,197.5		2,154.0		2,111.9
Proved undeveloped reserves, beginning balance		1,734.4				1,824.2
Proved undeveloped reserve, ending balance		1,510.8		1,734.4				1,824.2
Proved Undeveloped Reserves [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]					0.0
Pricing Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]	756.9		22.9		80.0
Pricing Revisions [Member] | Natural Gas [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty				21.9		68.4
Performance Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]	82.2		248.5		265.5
Operating Cost Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]			39.2		42.0
Other Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]	403.2		197.7		101.0
Williston Basin [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]					217.6
Williston Basin [Member] | Total Reserves Natural Gas Equivalent [Member]
Reserve Quantities [Line Items]
Extensions and discoveries		409.3	[6]	123.3	[8]
Pinedale [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]					265.3
Pinedale [Member] | Total Reserves Natural Gas Equivalent [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[8]			133.6
Pinedale [Member] | Performance Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]			194.0		129.5
Haynesville [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]					175.9
Haynesville [Member] | Performance Revisions [Member]
Reserve Quantities [Line Items]
Revisions of Previous Estimates - Qty	[3]					112.7
Uinta Basin [Member] | Total Reserves Natural Gas Equivalent [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]	318.9
Permian Basin [Member] | Total Reserves Natural Gas Equivalent [Member]
Reserve Quantities [Line Items]
Extensions and discoveries	[6]	297.8

[1] Revisions of previous estimates in 2015 include: 756.9 Bcfe of negative revisions due to lower pricing and 403.2 Bcfe of negative revisions unrelated to pricing, partially offset by 82.2 Bcfe of positive performance revisions. Negative pricing revisions were driven by lower gas, oil, and NGL prices. Negative other revisions included operating in ethane rejection in Pinedale and Uinta Basin.

[2] Revisions of previous estimates in 2014 include 248.5 Bcfe negative performance revisions partially offset by positive other revisions of 197.7 Bcfe, operating cost revisions of 39.2 Bcfe and pricing revisions of 22.9 Bcfe. Negative performance revisions were driven by a 194.0 Bcfe decrease in Pinedale reserves related to downward forecast revisions on proved developed (PDP) wells, additional production history on PUD to PDP performance and a downward adjustment in the number of PUD locations. Other negative revisions related to adjustments to shrink and lease operating expense deducts. Pricing revisions were primarily due to increased gas prices, which increased reserves by 21.9 Bcfe.

[3] Revisions of previous estimates in 2013 include positive impacts due to 80.0 Bcfe pricing revisions, negative performance revisions of 265.5 Bcfe, 42.0 Bcfe negative operating cost revisions and 101.0 Bcfe other negative revisions. Pricing revisions were primarily due to increased gas prices, which increased reserves by 68.4 Bcfe. Negative performance revisions were driven by a 129.5 Bcfe decrease in Pinedale reserves and 112.7 Bcfe decrease in Haynesville reserves related to reserve adjustments based on additional production history, well performance and current pricing causing a revised future development plan, which includes lower density drilling and a change in well spacing assumptions in some areas.

[4] Extensions and discoveries in 2015 increased proved reserves by 1,111.9 Bcfe, primarily related to extensions and discoveries in Williston Basin of 409.3 Bcfe, Uinta Basin of 318.9 Bcfe, and Permian Basin of 297.8 Bcfe. All of these extensions and discoveries related to new well completions and the associated new PUD locations as part of the Company's development drilling plans and new compression well projections in Pinedale.

[5] Extensions and discoveries in 2014 increased proved reserves by 294.1 Bcfe, primarily related to extensions and discoveries in Pinedale of 133.6 Bcfe and the Williston Basin of 123.3 Bcfe. All of these extensions and discoveries related to new well completions and the associated new PUD locations as part of the Company's development drilling plans and new compression well projections in Pinedale.

[6] Extensions and discoveries in 2013 increased proved reserves by 783.8 Bcfe, primarily related to extensions and discoveries in the Williston Basin of 217.6 Bcfe, in Pinedale of 265.3 Bcfe, and 175.9 Bcfe in Haynesville. Extension and discoveries in Pinedale and Haynesville relate to certain less densely spaced wells with higher estimates of recoverable oil and gas, which were booked to replace wells removed from the Company's reserves through negative revisions caused by a change in well spacing assumptions in these areas. Of these extensions and discoveries, 687.6 Bcfe related to new PUD locations

[7] Purchase of reserves in place in 2015 related to the acquisition of additional interests in QEP's operated wells in the Williston Basin as discussed in Note 2 – Acquisitions and Divestitures

[8] Purchase of reserves in place in 2014 relate to the Company's Permian Basin Acquisition as discussed in Note 2 – Acquisitions and Divestitures.

[9] Sale of reserves in place in 2015 relate to the divestiture of QEP's interest in certain non-core properties as discussed in Note 2 – Acquisitions and Divestitures.

[10] Sale of reserves in place primarily related to property sales in the Midcontinent in the second and fourth quarters of 2014 as discussed in Note 2 – Acquisitions and Divestitures