Supplemental Gas and Oil Information (Unaudited) Estimated Quantities of Proved Gas and Oil Reserves (Details) MMBoe in Millions, MMBbls in Millions, Bcf in Billions		12 Months Ended
		Dec. 31, 2017 MMBoe Bcf MMBbls		Dec. 31, 2016 MMBoe Bcf MMBbls		Dec. 31, 2015 MMBoe Bcf MMBbls
Reserve Quantities [Line Items]
Extensions and discoveries | MMBoe						185.4
Oil [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance		238.6		193.1		172.5
Revisions of previous estimates		3.7	[1]	(9.7)	[2]	(47.0)	[3]
Extensions and discoveries		59.1	[4]	13.0	[5]	85.6	[6]
Purchase of reserves in place		46.6	[7]	62.7	[8]	2.0	[9]
Sale of reserves in place		(7.9)	[10]	(0.2)	[11]	(0.4)	[12]
Production		(19.6)		(20.3)		(19.6)
Proved reserves balance, ending balance		320.5		238.6		193.1
Proved undeveloped reserves, beginning balance		135.4		83.4		73.2
Proved undeveloped reserve, ending balance		204.5		135.4		83.4
Proved developed reserves, beginning balance		103.2		109.7		99.3
Proved developed reserves, ending balance		116.0		103.2		109.7
Gas [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance | Bcf		2,553.8		2,108.9		2,317.2
Revisions of previous estimates | Bcf		12.5	[1]	412.8	[2]	(463.8)	[3]
Extensions and discoveries | Bcf		101.9	[4]	158.1	[5]	467.7	[6]
Purchase of reserves in place | Bcf		125.5	[7]	54.6	[8]	3.2	[9]
Sale of reserves in place | Bcf		(831.2)	[10]	(3.6)	[11]	(34.3)	[12]
Production | Bcf		(168.9)		(177.0)		(181.1)
Proved reserves balance, ending balance | Bcf		1,793.6		2,553.8		2,108.9
Proved undeveloped reserves, beginning balance | Bcf		1,244.0		863.6		1,028.8
Proved undeveloped reserve, ending balance | Bcf		1,138.1		1,244.0		863.6
Proved developed reserves, beginning balance | Bcf		1,309.8		1,245.3		1,288.4
Proved developed reserves, ending balance | Bcf		655.5		1,309.8		1,245.3
Natural Gas Liquids [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance		67.2		58.8		96.6
Revisions of previous estimates		(3.1)	[1]	(0.3)	[2]	(55.3)	[3]
Extensions and discoveries		10.4	[4]	3.3	[5]	21.8	[6]
Purchase of reserves in place		8.7	[7]	11.5	[8]	0.6	[9]
Sale of reserves in place		(12.6)	[10]	(0.1)	[11]	(0.2)	[12]
Production		(5.4)		(6.0)		(4.7)
Proved reserves balance, ending balance		65.2		67.2		58.8
Proved undeveloped reserves, beginning balance		31.5		24.4		44.4
Proved undeveloped reserve, ending balance		37.3		31.5		24.4
Proved developed reserves, beginning balance		35.7		34.4		52.2
Proved developed reserves, ending balance		27.9		35.7		34.4
Barrels of oil equivalent production [Member]
Reserve Quantities [Line Items]
Proved developed and undeveloped reserves, beginning balance | MMBoe	[13]	731.4		603.4		655.3
Revisions of previous estimates | MMBoe	[13]	2.7	[1]	58.8	[2]	(179.6)	[3]
Extensions and discoveries | MMBoe	[13]	86.4	[4]	42.6	[5]	185.4	[6]
Purchase of reserves in place | MMBoe	[13]	76.3	[7]	83.3	[8]	3.1	[9]
Sale of reserves in place | MMBoe	[13]	(159.0)	[10]	(0.9)	[11]	(6.3)	[12]
Production | MMBoe	[13]	(53.1)		(55.8)		(54.5)
Proved developed and undeveloped reserves, ending balance | MMBoe	[13]	684.7		731.4		603.4
Proved undeveloped reserves, beginning balance | MMBoe		374.2		251.8		289.1
Proved undeveloped reserves, ending balance | MMBoe		431.6		374.2		251.8
Proved developed reserves, beginning balance | MMBoe		357.2		351.6		366.2
Proved developed reserves, ending balance | MMBoe		253.1		357.2		351.6
Pricing Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		32.0		18.5		126.2
Performance Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		2.2		5.5		13.7
Positive revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		2.7		77.3
Operating Cost Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		11.0
Other Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe						67.2
Development plan change [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		20.5
Williston Basin [Member]
Reserve Quantities [Line Items]
Extensions and discoveries | MMBoe						68.2
Uinta Basin [Member]
Reserve Quantities [Line Items]
Extensions and discoveries | MMBoe						53.2
Permian Basin [Member]
Reserve Quantities [Line Items]
Extensions and discoveries | MMBoe						49.6

[1] Revisions of previous estimates in 2017 include 2.7 MMboe of positive revisions, primarily related to 32.0 MMboe of positive revisions related to pricing, driven by higher oil, gas and NGL prices and 2.2 MMboe of positive performance revisions. These positive revisions were partially offset by 11.0 MMboe of negative revisions related to higher operating costs and 20.5 MMboe of other revisions primarily from changing to a horizontal development plan from a vertical well development plan in the Uinta Basin and increased longer laterals in Haynesville/Cotton Valley. These negative other revisions are partially offset by positive other revisions from successful infill drilling in Haynesville/Cotton Valley and the Williston Basin.

[2] Revisions of previous estimates in 2016 include 77.3 MMboe of positive revisions, primarily related to successful workovers in Haynesville/Cotton Valley; reserves associated with increased density wells in areas that have been previously developed on lower density spacing; and 5.5 MMboe of positive performance revisions. These positive revisions were partially offset by 18.5 MMboe of negative revisions related to pricing, driven by lower oil, gas and NGL prices.

[3] Revisions of previous estimates in 2015 include: 126.2 MMboe of negative revisions due to lower pricing and 67.2 MMboe of negative revisions unrelated to pricing, partially offset by 13.7 MMboe of positive performance revisions. Negative pricing revisions were driven by lower oil, gas and NGL prices. Negative other revisions included operating in ethane rejection in Pinedale and the Uinta Basin.

[4] Extensions and discoveries in 2017 primarily related to new well completions and associated new PUD locations in the Permian Basin.

[5] Extensions and discoveries in 2016 were primarily in the Permian and Uinta basins and related to new well completions and associated new PUD locations.

[6] Extensions and discoveries in 2015 increased proved reserves by 185.4 MMboe, primarily related to extensions and discoveries in the Williston Basin of 68.2 MMboe, the Uinta Basin of 53.2 MMboe, and the Permian Basin of 49.6 MMboe. All of these extensions and discoveries related to new well completions and associated new PUD locations.

[7] Purchase of reserves in place in 2017 was primarily related to QEP's 2017 Permian Basin Acquisition and various other acquired oil and gas properties as discussed in Note 2 – Acquisitions and Divestitures.

[8] Purchase of reserves in place in 2016 primarily relates to QEP's 2016 Permian Basin Acquisition as discussed in Note 2 – Acquisitions and Divestitures.

[9] Purchase of reserves in place in 2015 related to the acquisition of additional interests in QEP operated wells in the Williston and Permian basins as discussed in Note 2 – Acquisitions and Divestitures.

[10] Sale of reserves in place in 2017 was primarily related to QEP's Pinedale Divestiture as discussed in Note 2 – Acquisitions and Divestitures.

[11] Sale of reserves in place in 2016 relates to the divestiture of QEP's interest in certain non-core properties as discussed in Note 2 – Acquisitions and Divestitures.

[12] 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.

[13] Generally, gas consumed in operations was excluded from reserves, however, in some cases, produced gas consumed in operations was included in reserves when the volumes replaced fuel purchases.