Market Risk Benefits - Rollforward of Balances for Variable Annuity Products (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Variable Annuties
Market Risk Benefit [Roll Forward]
Balance, beginning of period	$ 4,550,625	$ 8,884,362	$ 13,577,543
Effect of cumulative changes in non-performance risk	1,727,910	287,605	722,837
Balance, beginning of period, before effect of changes in non-performance risk	6,278,535	9,171,967	14,300,380
Attributed fees collected	1,158,879	1,249,956	1,368,434
Claims Paid	(85,898)	(64,406)	(29,401)
Interest accrual	293,205	143,483	24,824
Actual in force different from expected	79,030	105,996	(19,290)
Effect of changes in interest rates	(1,438,873)	(7,271,427)	(3,461,436)
Effect of changes in equity markets	(1,845,207)	3,103,563	(2,789,777)
Effect of assumption update	330,769	(160,597)	(221,767)
Issuances	29,433
Other adjustments	(36,888)		0
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	4,762,985	6,278,535	9,171,967
Effect of cumulative changes in non-performance risk	(1,068,035)	(1,727,910)	(287,605)
Balance, end of period	3,694,950	4,550,625	8,884,362
Less: Reinsured Market Risk Benefits
Market Risk Benefit [Roll Forward]
Balance, beginning of period	(422,261)	(906,484)	(13,589,575)
Effect of cumulative changes in non-performance risk	0	0	0
Balance, beginning of period, before effect of changes in non-performance risk	(422,261)	(906,484)	(13,589,575)
Interest accrual	(53,016)	(13,438)	(16,593)
Actual in force different from expected	(13,338)	(9,968)	22,687
Effect of changes in interest rates	455,062	767,394	3,240,588
Effect of changes in equity markets	180,953	(326,575)	2,070,833
Effect of assumption update	(54,067)	23,171	221,767
Issuances	7,680
Other adjustments	(635,011)		8,223,470
Effect of changes in current period counterparty non-performance risk	(146,999)	187,910	(334,312)
Balance, end of period, before effect of changes in non-performance risk	(917,792)	(422,261)	(906,484)
Effect of cumulative changes in non-performance risk	0	0	0
Balance, end of period	(917,792)	(422,261)	(906,484)
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	(246,747)	(147,727)	(759,997)
Claims Paid	9,952	3,456	14,648
Total, Net of Reinsurance
Market Risk Benefit [Roll Forward]
Balance, beginning of period	4,128,364	7,977,878	(12,032)
Effect of cumulative changes in non-performance risk	1,727,910	287,605	722,837
Balance, beginning of period, before effect of changes in non-performance risk	5,856,274	8,265,483	710,805
Attributed fees collected	912,132	1,102,229	608,437
Claims Paid	(75,946)	(60,950)	(14,753)
Interest accrual	240,189	130,045	8,231
Actual in force different from expected	65,692	96,028	3,397
Effect of changes in interest rates	(983,811)	(6,504,033)	(220,848)
Effect of changes in equity markets	(1,664,254)	2,776,988	(718,944)
Effect of assumption update	276,702	(137,426)	0
Issuances	37,113
Other adjustments	(671,899)		8,223,470
Effect of changes in current period counterparty non-performance risk	(146,999)	187,910	(334,312)
Balance, end of period, before effect of changes in non-performance risk	3,845,193	5,856,274	8,265,483
Effect of cumulative changes in non-performance risk	(1,068,035)	(1,727,910)	(287,605)
Balance, end of period	$ 2,777,158	$ 4,128,364	$ 7,977,878