Income Taxes - Narrative (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2019	Mar. 31, 2018
Operating Loss Carryforwards [Line Items]
Tax benefit from Tax Reform Legislation and Toll Tax	$ 145
Tamar and Dalit Fields \| Disposed by sale
Operating Loss Carryforwards [Line Items]
Percentage of divestiture farmed out		7.50%

Amount of income tax expense (benefit) from effect of Tax Cuts and Jobs Act.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration