Investments in Fixed Maturity Securities (AFS Allowance for Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	$ 33,278	$ 18,911	$ 22,238	$ 1,782
Cumulative effect adjustment resulting from changes in accounting principles	34,595	16,887	34,595	16,887
Expected credit losses on securities for which credit losses were not previously recorded	1,044	82	3,123	19,088
Expected credit losses (gains) on securities for which credit losses were previously recorded	273	(2,106)	9,267	(3,484)
Reduction due to disposals			(33)	(499)
Allowance for expected credit losses, end of period	34,595	16,887	34,595	16,887
Foreign government
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	33,096	18,899	22,222	1,264
Cumulative effect adjustment resulting from changes in accounting principles	33,375	16,875	33,375	16,875
Expected credit losses on securities for which credit losses were not previously recorded	0	82	1,897	19,072
Expected credit losses (gains) on securities for which credit losses were previously recorded	279	(2,106)	9,289	(2,967)
Reduction due to disposals			(33)	(494)
Allowance for expected credit losses, end of period	33,375	16,875	33,375	16,875
Corporate
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	182	12	16	518
Cumulative effect adjustment resulting from changes in accounting principles	1,199	12	1,199	12
Expected credit losses on securities for which credit losses were not previously recorded	1,023	0	1,205	16
Expected credit losses (gains) on securities for which credit losses were previously recorded	(6)	0	(22)	(517)
Reduction due to disposals			0	(5)
Allowance for expected credit losses, end of period	1,199	$ 12	1,199	$ 12
Mortgage-backed
Debt Securities, Available-for-sale, Allowance for Credit Loss [Roll Forward]
Allowance for expected credit losses, beginning of period	0		0
Cumulative effect adjustment resulting from changes in accounting principles	21		21
Expected credit losses on securities for which credit losses were not previously recorded	21		21
Expected credit losses (gains) on securities for which credit losses were previously recorded	0		0
Reduction due to disposals			0
Allowance for expected credit losses, end of period	$ 21		$ 21