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Income Taxes (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2017 USD ($)
Income Tax Disclosure [Abstract] |
Reduction in net deferred income tax liabilities | $ 1,140

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- Definition Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Expense (Benefit) + References No definition available. + Details
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