Investments in Fixed Maturity Securities (AFS Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 646	$ 36,708
Change on securities for which credit losses were not previously recorded	10	562
Change on securities for which credit losses were previously recorded	(323)	(14,439)
Balance, end of period	333	22,831
Foreign government
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	216	29,603
Change on securities for which credit losses were not previously recorded	0	0
Change on securities for which credit losses were previously recorded	107	(9,124)
Balance, end of period	323	20,479
Mortgage-backed
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	430	158
Change on securities for which credit losses were not previously recorded	0	562
Change on securities for which credit losses were previously recorded	(430)	(158)
Balance, end of period	0	562
State and municipal
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	0	757
Change on securities for which credit losses were not previously recorded	10	0
Change on securities for which credit losses were previously recorded	0	(64)
Balance, end of period	10	693
Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	0	5,026
Change on securities for which credit losses were not previously recorded		0
Change on securities for which credit losses were previously recorded		(5,026)
Balance, end of period	0	0
Asset-backed
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	0	1,164
Change on securities for which credit losses were not previously recorded		0
Change on securities for which credit losses were previously recorded		(67)
Balance, end of period	$ 0	$ 1,097

Amount of allowance for credit loss on 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
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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- Definition

Amount of expense for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), for which no credit loss was previously recorded.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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- Definition

Amount of expense (reversal of expense) for allowance for credit loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), not intended to be sold and not more likely than not will be required to sell before recovery of amortized cost basis, with previously recorded allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479106/326-30-50-9

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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