Investments - Schedule of Fair Value of Fixed Maturity Investments Trading (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Schedule of Investments [Line Items]
Fixed maturity investments trading	$ 20,877,108	$ 14,351,402
U.S. treasuries
Schedule of Investments [Line Items]
Fixed maturity investments trading	10,060,203	7,180,129
Corporate
Schedule of Investments [Line Items]
Fixed maturity investments trading	6,499,075	4,390,568
Asset-backed
Schedule of Investments [Line Items]
Fixed maturity investments trading	1,491,695	1,077,302
Residential mortgage-backed
Schedule of Investments [Line Items]
Fixed maturity investments trading	1,420,362	710,429
Agencies
Schedule of Investments [Line Items]
Fixed maturity investments trading	489,117	395,149
Non-U.S. government
Schedule of Investments [Line Items]
Fixed maturity investments trading	483,576	383,838
Commercial mortgage-backed
Schedule of Investments [Line Items]
Fixed maturity investments trading	$ 433,080	$ 213,987