Market Risk Benefits - Rollforward of Balances for Variable Annuity Products (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Variable Annuties
Market Risk Benefit [Roll Forward]
Balance, beginning of period	$ 3,707,407	$ 4,550,625	$ 8,884,362
Effect of cumulative changes in non-performance risk	1,067,983	1,727,910	287,605
Balance, beginning of period, before effect of changes in non-performance risk	4,775,390	6,278,535	9,171,967
Attributed fees collected	1,095,139	1,158,879	1,249,956
Claims Paid	(57,083)	(85,898)	(64,406)
Interest accrual	226,734	293,205	143,483
Actual in force different from expected	49,864	79,030	105,996
Effect of changes in interest rates	(1,436,230)	(1,438,873)	(7,271,427)
Effect of changes in equity markets	(1,660,907)	(1,845,207)	3,103,563
Effect of assumption update	85,619	330,769	(160,597)
Issuances	70,965	29,433
Other adjustments	(34,183)	(24,483)
Effect of changes in current period counterparty non-performance risk	0	0	0
Balance, end of period, before effect of changes in non-performance risk	3,115,308	4,775,390	6,278,535
Effect of cumulative changes in non-performance risk	(626,845)	(1,067,983)	(1,727,910)
Balance, end of period	2,488,463	3,707,407	4,550,625
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Balance, beginning of period	(917,792)	(422,261)	(906,484)
Effect of cumulative changes in non-performance risk	0	0	0
Balance, beginning of period, before effect of changes in non-performance risk	(917,792)	(422,261)	(906,484)
Interest accrual	(56,043)	(53,016)	(13,438)
Actual in force different from expected	(21,062)	(13,338)	(9,968)
Effect of changes in interest rates	277,354	455,062	767,394
Effect of changes in equity markets	177,329	180,953	(326,575)
Effect of assumption update	3,984	(54,067)	23,171
Issuances		7,680
Other adjustments	11,566	(635,011)
Effect of changes in current period counterparty non-performance risk	(61,469)	(146,999)	187,910
Balance, end of period, before effect of changes in non-performance risk	(844,582)	(917,792)	(422,261)
Effect of cumulative changes in non-performance risk	0	0	0
Balance, end of period	(844,582)	(917,792)	(422,261)
Less: Reinsured Market Risk Benefits | Augustar
Market Risk Benefit [Roll Forward]
Other adjustments	638,000
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Attributed fees collected	(259,099)	(246,747)	(147,727)
Claims Paid	5,669	9,952	3,456
Issuances	(5,019)
Total, Net of Reinsurance
Market Risk Benefit [Roll Forward]
Balance, beginning of period	2,789,615	4,128,364	7,977,878
Effect of cumulative changes in non-performance risk	1,067,983	1,727,910	287,605
Balance, beginning of period, before effect of changes in non-performance risk	3,857,598	5,856,274	8,265,483
Attributed fees collected	836,040	912,132	1,102,229
Claims Paid	(51,414)	(75,946)	(60,950)
Interest accrual	170,691	240,189	130,045
Actual in force different from expected	28,802	65,692	96,028
Effect of changes in interest rates	(1,158,876)	(983,811)	(6,504,033)
Effect of changes in equity markets	(1,483,578)	(1,664,254)	2,776,988
Effect of assumption update	89,603	276,702	(137,426)
Issuances	65,946	37,113
Other adjustments	(22,617)	(659,494)
Effect of changes in current period counterparty non-performance risk	(61,469)	(146,999)	187,910
Balance, end of period, before effect of changes in non-performance risk	2,270,726	3,857,598	5,856,274
Effect of cumulative changes in non-performance risk	(626,845)	(1,067,983)	(1,727,910)
Balance, end of period	$ 1,643,881	$ 2,789,615	$ 4,128,364