Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Tax Examination [Line Items]
Income (Loss) before income taxes	$ 21	$ 2,058	$ (1,542)	$ 4,745
Income Tax Expense (Benefit)	257	(461)	109	$ (1,302)
Reversal of deferred tax assets	(120)
Refund from the Alberta Tax & Revenue Administration	48		$ 48
Effective tax rate			7.00%	27.00%
Decrease to our accrued income and other taxes liability	124
Adjustment to valuation allowances	$ 117	85	$ (229)	$ 191
Australia West Assets [Member] \| Operating Segments [Member] \| Asia Pacific and Middle East [Member]
Income Tax Examination [Line Items]
Before-tax gain (loss) on disposition			587
Income Tax Expense (Benefit)			10
Reversal of deferred tax assets			$ 92
U.K. Subsidiaries [Member]
Income Tax Examination [Line Items]
Income Tax Expense (Benefit)		$ 234

Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

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