Supplemental Oil and Gas Reserve Information - Unaudited - Additional Information (Detail)	12 Months Ended
Dec. 31, 2019 MBoe $ / bbl $ / MMBTU	Dec. 31, 2018 MBoe $ / bbl $ / MMBTU	Dec. 31, 2017 MBoe $ / MMBTU $ / bbl
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)	(63,349)	(16,850)	(19,200)
Percentage of net positive (negative) revisions	(20.00%)	(5.00%)	(6.00%)
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe)		(20,200)	(14,200)
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)			(5,000.0)
Additions due to extensions and discoveries (Energy)	63,861	38,358	51,153
Estimated extensions and discoveries of reserves associated with new wells (Energy)	10,300	9,000.0	17,900
Additional proved undeveloped reserves (Energy)	53,600	29,400	33,300
Percentage of reserves produced from wells in certain formations	63.00%	77.00%	100.00%
Percentage of proved undeveloped reserves			100.00%
Divested reserves associated with non-operated properties (Energy)	2,531	15,926	1,387
Purchases of reserves in place (Energy)	0	32,873	671
Unweighted arithmetic average first-day-of-the-month prices for oil, price per Bbl \| $ / bbl	55.85	65.66	51.34
Unweighted arithmetic average first-day-of-the-month prices for natural gas, price per MMBtu \| $ / MMBTU	2.62	3.16	2.99
Revision Due to Performance
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)	(51,200)	(42,300)	(39,100)
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe)	(30,200)	(33,000.0)	(29,700)
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)	21,100	(9,300)	(9,400)
Revision of Previous Estimate Due to Realized Prices
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)	11,200	14,400	16,100
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe)	(9,600)	12,200	14,100
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)		2,200	2,000.0
Revision of Previous Estimate Due to (Mis)Alignment With Development Plan
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)	(7,600)	(9,400)	(2,100)
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)	(7,000.0)	(9,400)	(1,800)
Revision of Previous Estimate Due to Lower Operating Expenses
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)	(6,700)
Positive (negative) revisions of previous estimates - proved developed reserves (MMBoe)	5,100
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)	(1,700)
Revisions Due to Addition of Proved Undeveloped Reserves (PUDs)
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)		14,700
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)		14,700
Revision of Previous Estimate Due to Ownership Adjustments
Reserve Quantities [Line Items]
Net positive (negative) revisions of previous estimates (MMBoe)		5,400	2,500
Positive (negative) revisions of previous estimates - proved undeveloped reserves (MMBoe)		5,600	2,600
Bakken or Three Forks Formations Area
Reserve Quantities [Line Items]
Percentage of reserves produced from wells in certain formations	60.00%
Percentage of proved undeveloped reserves	37.00%	76.00%
Delaware Basin
Reserve Quantities [Line Items]
Percentage of reserves produced from wells in certain formations	40.00%	23.00%
Percentage of proved undeveloped reserves		24.00%

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Estimated extensions and discoveries of reserves associated with new wells

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Percentage of proved undeveloped reserves.

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Percentage of reserves produced from wells in certain formations.

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Proved Developed Reserve, Revision of Previous Estimate

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Revisions as a percentage of beginning of the years reserves balance.

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Proved Undeveloped Reserve, Revision of Previous Estimate

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Unweighted arithmetic average first-day-of-the-month prices

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Unweighted arithmetic average first-day-of-the-month prices for natural gas

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Energy measure of increase in quantity of proved reserve of oil and gas resulting from the extension of the proved acreage of previously discovered reservoir or discovery of new field with proved reserve or of new reservoir of proved reserve in old field, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Energy measure of increase in quantity of proved reserve of oil and gas resulting from purchase of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Form 20-F
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-Subsection Instruction 2

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Energy measure of increase (decrease) in quantity of proved reserve of oil and gas related to revision of a previous estimate resulting from new information, except for an increase in proved acreage, or change in economic factors, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
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Energy measure of decrease in quantity of proved reserve of oil and gas resulting from sale of mineral in place, stated in a unit of energy. For example, but not limited to, barrel of oil equivalents (BOE) or one thousand cubic feet of natural gas equivalent (Mcfe).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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