Fair Value Measurements - Schedule of Reconciliation of Level 3 Investments Securities (Footnotes) (Details) - USD ($) $ in Millions |
Sep. 30, 2019 |
Dec. 31, 2018 |
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| Estimated Fair Value | ||
| Securities with a loss shorter than 12 months | $ 0 | $ 82 |
| Securities with a loss shorter than 12 months | 0 | 1 |
| Unrealized Losses | ||
| Securities with a loss longer than 12 months | 17 | 67 |
| Securities with a loss longer than 12 months | $ 1 | $ 3 |
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- Definition Debt Securities, Available-For-Sale, Continuous Unrealized Loss Position, Fair Value [Abstract] No definition available.
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- References No definition available.
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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