Investments - Investments (Details) - USD ($) $ in Millions |
Dec. 31, 2020 |
Dec. 31, 2019 |
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| Investments, Debt and Equity Securities [Abstract] | ||
| Available-for-sale securities | $ 321 | $ 591 |
| Held-to-maturity securities | 162 | 97 |
| Investments | $ 483 | $ 688 |
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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). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity). Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Sum of the carrying amounts as of the balance sheet date of all investments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- References No definition available.
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