Investments and Fair Value Measurement - Change In Equity Securities (Details) - USD ($) $ in Millions |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Fair Value Disclosures [Abstract] | ||
| Initial cost basis | $ 6,075 | $ 6,001 |
| Upward adjustments | 1,984 | 1,984 |
| Downward adjustments (including impairment) | 0 | 0 |
| Total carrying value at the end of the period | $ 8,059 | $ 7,985 |
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- Definition Equity Securities Without Readily Determinable Fair Value, Cost Basis, Cumulative Amount No definition available.
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- Definition Amount of investment in equity security without readily determinable fair value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cumulative loss from downward price adjustment on investment in equity security without readily determinable fair value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cumulative gain from upward price adjustment on investment in equity security without readily determinable fair value. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- References No definition available.
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