Income Taxes - Schedule of Reserve for Uncertain Tax Positions That May BE Challenged (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] | ||
| Gross unrecognized tax benefits, beginning of period | $ 102 | $ 5 |
| Gross increases: | ||
| Current year tax positions | 43 | 6 |
| Prior year tax positions | 113 | 93 |
| Gross decreases: | ||
| Prior year tax positions | 0 | (1) |
| Statute of limitation lapses | (1) | (1) |
| Gross unrecognized tax benefits, end of period | $ 257 | $ 102 |
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- Definition Gross Decreases [Abstract] No definition available.
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- Definition Gross Increases [Abstract] No definition available.
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
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- Definition Amount of unrecognized tax benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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