Investments (Narrative) (Details) $ in Thousands |
Sep. 30, 2026
USD ($)
securities
|
Dec. 31, 2025
USD ($)
securities
|
|---|---|---|
| Investments, Debt and Equity Securities [Abstract] | ||
| Available-for-sale fixed maturity securities in unrealized loss position, number of positions | securities | 1,663 | 948 |
| Available-for-sale securities, estimated fair value | $ 18,270,346 | $ 7,763,106 |
| Available-for-sale securities, gross unrealized holding losses | $ (920,122) | $ (331,436) |
| Number of available-for-sale fixed maturity securities positions in a continuous unrealized loss position for one year or longer at period end | securities | 716 | 851 |
| Available-for-sale securities, estimated fair value, 12 months or longer | $ 5,633,989 | $ 6,816,461 |
| Available-for-sale securities, gross unrealized holding losses, 12 months or longer | (537,817) | (327,375) |
| Investments, available-for-sale, allowance for credit losses | $ 0 | $ 0 |
| X | ||||||||||
- Definition Investments, Available-for-sale, Allowance for Credit Loss No definition available.
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| X | ||||||||||
- 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/exampleRef
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| X | ||||||||||
- 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://fasb.org/us-gaap/role/ref/otherTransitionRef
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| X | ||||||||||
- Definition Number of investments in debt securities 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 an allowance for credit loss. Includes beneficial interest in securitized financial asset. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- 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/exampleRef
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| X | ||||||||||
- 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://fasb.org/us-gaap/role/ref/otherTransitionRef
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| X | ||||||||||
- Definition Number of investments in debt securities 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://fasb.org/us-gaap/role/ref/otherTransitionRef
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| X | ||||||||||
- References No definition available.
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