IMPAIRMENT OF ASSETS (Schedule of Impairments) (Details) - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
Feb. 08, 2018	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Impairment of Cimarron investment		$ 15,963
Total impairment of assets	$ 0	3,205,051	$ 905,293
Upstream
Segment Reporting Information [Line Items]
Impairment of unproved properties	0	742,065	31,023
Impairment of proved properties	0	1,291,647	484,830
Impairment of operating lease right-of-use assets			13,245
Impairment of other long-term assets	0	0	27,329
Total impairment of assets	0	2,033,712	556,427	$ 2,000,000
Midstream
Segment Reporting Information [Line Items]
Impairment of operating lease right-of-use assets			269
Impairment of property and equipment	0	68,407	348,597	68,400
Impairment of Cimarron investment	0	15,963	0
Impairment of intangible assets	0	394,999	0	$ 395,000
Impairment of goodwill	0	691,970	0
Total impairment of assets	$ 0	$ 1,171,339	$ 348,866

Impairment Expense Of Operating Lease, Right-Of-Use Asset

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Impairment expense related to proved oil and gas properties

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Impairment expense related to unproved oil and gas properties

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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This item represents an other than temporary decline in value that has been recognized against an investment accounted for under the equity method of accounting. The excess of the carrying amount over the fair value of the investment represents the amount of the write down which is or was reflected in earnings. The written down value is a new cost basis with the adjusted value of the investment becoming its new carrying value subject to the equity accounting method. Evidence of a loss in value might include, but would not necessarily be limited to, absence of an ability to recover the carrying amount of the investment or inability of the investee to sustain an earnings capacity which would justify the carrying amount of the investment.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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The charge against earnings resulting from the write down of long lived assets other than goodwill due to the difference between the carrying value and lower fair value.

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Amount of increase (decrease) of physical assets used in the normal conduct of business and not intended for resale, from reclassification, impairment, donation, or changes classified as other. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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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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