Short-term and Long-term Investments, Restricted Deposits - Narrative (Details) $ in Millions |
6 Months Ended | |
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Jun. 30, 2021
USD ($)
position
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Dec. 31, 2020
USD ($)
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| Schedule Of Investments And Restricted Deposits By Type [Line Items] | ||
| Accrued interest income | $ | $ 92 | $ 86 |
| Positions from which gross unrealized losses were generated | 1,512 | |
| Total unrealized investment positions | 6,515 | |
| Commercial mortgage-backed securities | ||
| Schedule Of Investments And Restricted Deposits By Type [Line Items] | ||
| Investments recorded at fair value that carry rating of AA Plus, weighted average (in years) | 4 years | |
| Rated Securities | External Credit Rating, Investment Grade | Investment Securities | ||
| Schedule Of Investments And Restricted Deposits By Type [Line Items] | ||
| Percentage of investments in rated securities carry an investment grade rating by nationally recognized statistical rating organizations | 97.00% |
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- Definition Investments Recorded At Fair Value That Carry Rating Of A A Plus, Weighted Average, Duration No definition available.
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- Definition Positions from which gross unrealized losses were generated No definition available.
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- Definition Total Unrealized Investment Positions No definition available.
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- Definition Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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