Market Risk Benefits - Rollforward of Balances for Variable and Fixed Annuity Products (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Variable Annuities
Market Risk Benefit [Roll Forward]
Balance, beginning of period	$ 2,488,463	$ 3,707,407
Effect of cumulative changes in non-performance risk	626,845	1,067,983
Balance, beginning of period, before effect of changes in non-performance risk	3,115,308	4,775,390
Attributed fees collected	512,592	556,055
Claims paid	(29,170)	(31,466)
Interest accrual	86,362	119,334
Actual in force different from expected	39,371	(2,637)
Effect of changes in interest rates	370,996	(870,637)
Effect of changes in equity markets	(469,011)	(1,112,214)
Effect of assumption update and other refinements	120,191	82,619
Issuances	34,790	28,190
Other adjustments	(1,957)	5,379
Effect of changes in current period counterparty non-performance risk	0	0
Balance, end of period, before effect of changes in non-performance risk	3,779,472	3,550,013
Effect of cumulative changes in non-performance risk	(788,567)	(884,110)
Balance, end of period	2,990,905	2,665,903
Individual Fixed
Market Risk Benefit [Roll Forward]
Balance, beginning of period	0	0
Effect of cumulative changes in non-performance risk	0	0
Balance, beginning of period, before effect of changes in non-performance risk	0	0
Attributed fees collected	5,706	0
Claims paid	0	0
Interest accrual	0
Actual in force different from expected	2,019	0
Effect of changes in interest rates	(6,749)	0
Effect of changes in equity markets	(2,404)	0
Effect of assumption update and other refinements	151,000	0
Issuances	16,891	0
Other adjustments	2,692	0
Effect of changes in current period counterparty non-performance risk	0	0
Balance, end of period, before effect of changes in non-performance risk	169,155	0
Effect of cumulative changes in non-performance risk	(6,600)	0
Balance, end of period	162,555	0
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Balance, beginning of period	(844,582)	(917,792)
Effect of cumulative changes in non-performance risk	0	0
Balance, beginning of period, before effect of changes in non-performance risk	(844,582)	(917,792)
Interest accrual	(24,541)	(28,372)
Actual in force different from expected	(10,759)	(10,203)
Effect of changes in interest rates	(113,288)	126,966
Effect of changes in equity markets	48,676	115,601
Effect of assumption update and other refinements	(23,026)	3,984
Other adjustments	83	398
Effect of changes in current period counterparty non-performance risk	66,897	(6,098)
Balance, end of period, before effect of changes in non-performance risk	(1,019,308)	(845,107)
Effect of cumulative changes in non-performance risk	0	0
Balance, end of period	(1,019,308)	(845,107)
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Attributed fees collected	(118,440)	(131,047)
Claims paid	3,094	3,110
Issuances	(3,422)	(1,654)
Total, Net of Reinsurance
Market Risk Benefit [Roll Forward]
Balance, beginning of period	1,643,881	2,789,615
Effect of cumulative changes in non-performance risk	626,845	1,067,983
Balance, beginning of period, before effect of changes in non-performance risk	2,270,726	3,857,598
Attributed fees collected	399,858	425,008
Claims paid	(26,076)	(28,356)
Interest accrual	61,821	90,962
Actual in force different from expected	30,631	(12,840)
Effect of changes in interest rates	250,959	(743,671)
Effect of changes in equity markets	(422,739)	(996,613)
Effect of assumption update and other refinements	248,165	86,603
Issuances	48,259	26,536
Other adjustments	818	5,777
Effect of changes in current period counterparty non-performance risk	66,897	(6,098)
Balance, end of period, before effect of changes in non-performance risk	2,929,319	2,704,906
Effect of cumulative changes in non-performance risk	(795,167)	(884,110)
Balance, end of period	$ 2,134,152	$ 1,820,796