Summary of Significant Accounting Principles - Change in Tax Law (Details) $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2017
USD ($)
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| Accounting Policies [Abstract] | |
| Estimated incremental income tax expense | $ 1,900 |
| Adjustment of deferred tax asset | $ 946 |
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- Definition Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit) No definition available.
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- Definition Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Investment Valuation Adjustment No definition available.
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| X | ||||||||||
- References No definition available.
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