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Income Taxes - Schedule of Impact of Tax Cuts and Jobs Act of 2017 (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | 24 Months Ended
--- | --- | --- | ---
Dec. 31, 2017 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2018
Income Tax Disclosure [Abstract] |  |  |  |
Transition tax |  | $ 36 |  |
Re-measurement of deferred tax balances |  | (8) |  |
Indefinite reinvestment assertion |  | 1 |  |
Allocation of tax benefit from foreign tax credits |  | 59 |  |
Total income tax expense (benefit) |  | $ 88 |  |
Transition tax |  |  | $ 264 |
Re-measurement of deferred tax balances |  |  | 86 |
Indefinite reinvestment assertion |  |  | $ (5) |
Total income tax expense (benefit) | $ 345 |  |  |
Transition tax |  |  |  | $ 300
Re-measurement of deferred tax balances |  |  |  | 78
Indefinite reinvestment assertion |  |  |  | (4)
Allocation of tax benefit from foreign tax credits |  |  |  | 59
Total income tax expense (benefit) |  |  |  | $ 433

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