Dispositions - International Segment (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
Jul. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of oil and gas property and equipment		$ 3	$ 13
Income before income taxes		$ (49)	27
International E&P \| U.K. Business \| Disposal Group, Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of oil and gas property and equipment	$ 95
Income before income taxes			$ (10)

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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