Investments in Fixed Maturity Securities (AFS Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 26,153	$ 20,009	$ 22,238	$ 1,782
Cumulative effect adjustment resulting from changes in accounting principles	33,278	18,911	33,278	18,911
Expected credit losses on securities for which credit losses were not previously recorded	1,595	0	2,079	19,006
Expected credit losses (gains) on securities for which credit losses were previously recorded	5,563	(604)	8,994	(1,378)
Reduction due to disposals	(33)	(494)	(33)	(499)
Allowance for expected credit losses, end of period	33,278	18,911	33,278	18,911
Foreign government
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	26,153	19,993	22,222	1,264
Cumulative effect adjustment resulting from changes in accounting principles	33,096	18,899	33,096	18,899
Expected credit losses on securities for which credit losses were not previously recorded	1,413	0	1,897	18,990
Expected credit losses (gains) on securities for which credit losses were previously recorded	5,563	(600)	9,010	(861)
Reduction due to disposals	(33)	(494)	(33)	(494)
Allowance for expected credit losses, end of period	33,096	18,899	33,096	18,899
Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	0	16	16	518
Cumulative effect adjustment resulting from changes in accounting principles	182	12	182	12
Expected credit losses on securities for which credit losses were not previously recorded	182	0	182	16
Expected credit losses (gains) on securities for which credit losses were previously recorded	0	(4)	(16)	(517)
Reduction due to disposals	0	0	0	(5)
Allowance for expected credit losses, end of period	$ 182	$ 12	$ 182	$ 12

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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922900-210455

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 9
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=124269663&loc=SL82922900-210455

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aaa)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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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.

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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.

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

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Amount of decrease in 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) from sale.

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