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, 2019 MMBoe Bcf MMBbls		Dec. 31, 2018 MMBoe Bcf MMBbls		Dec. 31, 2017 MMBoe Bcf MMBbls
Oil [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance		339.1		320.5		238.6
Revisions of previous estimates		(94.9)	[1]	2.1	[2]	3.7	[3]
Extensions and discoveries		33.6	[4]	57.1	[5]	59.1	[6]
Purchase of reserves in place		3.6	[7]	8.2	[8]	46.6	[9]
Sale of reserves in place		(4.9)	[10]	(24.9)	[11]	(7.9)	[12]
Production		(21.6)		(23.9)		(19.6)
Proved reserves balance, ending balance		254.9		339.1		320.5
Proved undeveloped reserves, beginning balance		205.5		204.5		135.4
Proved undeveloped reserve, ending balance		137.4		205.5		204.5
Proved developed reserves, beginning balance		133.6		116.0		103.2
Proved developed reserves, ending balance		117.5		133.6		116.0
Gas [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance | Bcf		1,487.6		1,793.6		2,553.8
Revisions of previous estimates | Bcf		(23.0)	[1]	314.0	[2]	12.5	[3]
Extensions and discoveries | Bcf		40.0	[4]	56.5	[5]	101.9	[6]
Purchase of reserves in place | Bcf		4.0	[7]	7.9	[8]	125.5	[9]
Sale of reserves in place | Bcf		(1,102.2)	[10]	(544.8)	[11]	(831.2)	[12]
Production | Bcf		(33.1)		(139.6)		(168.9)
Proved reserves balance, ending balance | Bcf		373.3		1,487.6		1,793.6
Proved undeveloped reserves, beginning balance | Bcf		1,105.3		1,138.1		1,244.0
Proved undeveloped reserve, ending balance | Bcf		156.3		1,105.3		1,138.1
Proved developed reserves, beginning balance | Bcf		382.3		655.5		1,309.8
Proved developed reserves, ending balance | Bcf		217.0		382.3		655.5
Natural Gas Liquids [Member]
Reserve Quantities [Line Items]
Proved reserves balance, beginning balance		71.2		65.2		67.2
Revisions of previous estimates		(8.7)	[1]	6.7	[2]	(3.1)	[3]
Extensions and discoveries		7.4	[4]	9.8	[5]	10.4	[6]
Purchase of reserves in place		0.7	[7]	1.3	[8]	8.7	[9]
Sale of reserves in place		(0.3)	[10]	(7.1)	[11]	(12.6)	[12]
Production		(5.1)		(4.7)		(5.4)
Proved reserves balance, ending balance		65.2		71.2		65.2
Proved undeveloped reserves, beginning balance		39.7		37.3		31.5
Proved undeveloped reserve, ending balance		28.5		39.7		37.3
Proved developed reserves, beginning balance		31.5		27.9		35.7
Proved developed reserves, ending balance		36.7		31.5		27.9
Barrels of oil equivalent production [Member]
Reserve Quantities [Line Items]
Proved developed and undeveloped reserves, beginning balance | MMBoe	[13]	658.2		684.7		731.4
Revisions of previous estimates | MMBoe		(107.3)		61.0	[2],[13]	2.7	[3],[13]
Extensions and discoveries | MMBoe	[13]	47.6	[4]	76.3	[5]	86.4	[6]
Purchase of reserves in place | MMBoe	[13]	4.9	[7]	10.9	[8]	76.3	[9]
Sale of reserves in place | MMBoe	[13]	(188.9)	[10]	(122.8)	[11]	(159.0)	[12]
Production | MMBoe	[13]	(32.2)		(51.9)		(53.1)
Proved developed and undeveloped reserves, ending balance | MMBoe	[13]	382.3		658.2		684.7
Proved undeveloped reserves, beginning balance | MMBoe		429.3		431.6		374.2
Proved undeveloped reserves, ending balance | MMBoe		191.9		429.3		431.6
Proved developed reserves, beginning balance | MMBoe		228.9		253.1		357.2
Proved developed reserves, ending balance | MMBoe		190.4		228.9		253.1
Pricing Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		17.0		17.3		32.0
Performance Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		13.7		8.7		2.2
Positive revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		4.6		61.0		2.7
Operating Cost Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe				11.7		11.0
Other Revisions [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		10.9
Development plan change [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		44.5		23.4		20.5
Reduction In Future Capital Expenditures [Member]
Reserve Quantities [Line Items]
Revisions of previous estimates | MMBoe		25.8

[1] Revisions of previous estimates in 2019 totaling 107.3 MMboe of negative revisions includes 44.5 MMboe of negative PUD revisions as a result of changes to the development sequence in the Permian Basin, to maximize capital efficiency (see offset in extensions and discoveries footnote 10 below); 25.8 MMboe of PUD removals, primarily in the Williston Basin, that will not be developed within five years of the initial date of booking due to the reduction in future capital expenditures; 17.0 MMboe of negative revisions related to pricing, primarily driven by lower oil prices; 13.7 MMboe of negative performance revisions, primarily associated with updated volume projections for high-density wells and certain undrilled locations in the Permian Basin; 10.9 MMboe of other negative revisions, partially offset by 4.6 MMboe of positive revisions related to lower operating costs.

[2] Revisions of previous estimates in 2018 totaling 61.0 MMboe of positive revisions include 23.4 MMboe of other revisions, primarily related to changing our development plans in the Haynesville/Cotton Valley; 17.3 MMboe of positive revisions related to pricing, primarily driven by higher oil prices; 11.7 MMboe of positive revisions related to lower operating costs; and 8.7 MMboe of positive performance revisions.

[3] 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.

[4] Extensions and discoveries in 2019 primarily related to new PUD locations in the Permian Basin due to changes in the development sequence in the Permian Basin to maximize capital efficiency. See partial offset in revisions to previous estimates in footnote 9 above.

[5] Extensions and discoveries in 2018 primarily related to new well completions and associated new PUD locations in the Permian Basin.

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

[7] Purchase of reserves in place in 2019 primarily relates to the additional acquisitions in the Permian Basin as discussed in Note 3 – Acquisitions and Divestitures.

[8] Purchase of reserves in place in 2018 primarily relates to the additional acquisitions in the Permian Basin as discussed in Note 3 – Acquisitions and Divestitures.

[9] 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 3 – Acquisitions and Divestitures.

[10] Sale of reserves in place in 2019 was primarily related to QEP's Haynesville Divestiture as discussed in Note 3 – Acquisitions and Divestitures.

[11] Sale of reserves in place in 2018 was primarily related to QEP's Uinta Basin Divestiture as discussed in Note 3 – Acquisitions and Divestitures.

[12] Sale of reserves in place in 2017 was primarily related to QEP's Pinedale Divestiture as discussed in Note 3 – Acquisitions and Divestitures.

[13] lly, 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.
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