Market Risk Benefits - Rollforward of Balances for Variable Annuity Products (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Variable Annuities
Market Risk Benefit [Roll Forward]
Balance, beginning of period	$ 3,694,950	$ 4,550,625
Effect of cumulative changes in non-performance risk	1,068,035	1,727,910
Balance, beginning of period, before effect of changes in non-performance risk	4,762,985	6,278,535
Attributed fees collected	556,055	587,663
Claims paid	(31,466)	(43,782)
Interest accrual	119,334	160,106
Actual in force different from expected	(2,637)	36,193
Effect of changes in interest rates	(870,637)	(671,989)
Effect of changes in equity markets	(1,112,214)	(1,314,461)
Effect of assumption update	85,619	330,769
Issuances	28,190	11,403
Other adjustments	14,784	(17,436)
Effect of changes in current period counterparty non-performance risk	0	0
Balance, end of period, before effect of changes in non-performance risk	3,550,013	5,357,001
Effect of cumulative changes in non-performance risk	(884,110)	(1,660,587)
Balance, end of period	2,665,903	3,696,414
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Balance, beginning of period	(917,792)	(422,261)
Effect of cumulative changes in non-performance risk	0	0
Balance, beginning of period, before effect of changes in non-performance risk	(917,792)	(422,261)
Interest accrual	(28,372)	(20,505)
Actual in force different from expected	(10,203)	(6,069)
Effect of changes in interest rates	126,966	169,229
Effect of changes in equity markets	115,601	127,157
Effect of assumption update	3,984	(54,067)
Other adjustments	398	(638,198)
Effect of changes in current period counterparty non-performance risk	(6,098)	(7,445)
Balance, end of period, before effect of changes in non-performance risk	(845,107)	(946,878)
Effect of cumulative changes in non-performance risk	0	0
Balance, end of period	(845,107)	(946,878)
Less: Reinsured Market Risk Benefits | AuguStar [Member]
Market Risk Benefit [Roll Forward]
Other adjustments	638,000
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Attributed fees collected	(131,047)	(107,425)
Claims paid	3,110	3,681
Issuances	(1,654)	9,025
Total, Net of Reinsurance
Market Risk Benefit [Roll Forward]
Balance, beginning of period	2,777,158	4,128,364
Effect of cumulative changes in non-performance risk	1,068,035	1,727,910
Balance, beginning of period, before effect of changes in non-performance risk	3,845,193	5,856,274
Attributed fees collected	425,008	480,238
Claims paid	(28,356)	(40,101)
Interest accrual	90,962	139,601
Actual in force different from expected	(12,840)	30,124
Effect of changes in interest rates	(743,671)	(502,760)
Effect of changes in equity markets	(996,613)	(1,187,304)
Effect of assumption update	89,603	276,702
Issuances	26,536	20,428
Other adjustments	15,182	(655,634)
Effect of changes in current period counterparty non-performance risk	(6,098)	(7,445)
Balance, end of period, before effect of changes in non-performance risk	2,704,906	4,410,123
Effect of cumulative changes in non-performance risk	(884,110)	(1,660,587)
Balance, end of period	$ 1,820,796	$ 2,749,536