Investments - Schedule of Fixed Maturities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Amortized Cost, net
Due in one year or less	$ 126,902
Due after one year through five years	728,959
Due after five years through ten years	1,869,090
Due after ten years through twenty years	8,729,774
Due after twenty years	7,254,503
Mortgage-backed and asset-backed securities	116,186
Fixed maturities, net of allowance for credit losses	18,825,414
Fair Value
Due in one year or less	126,643
Due after one year through five years	741,488
Due after five years through ten years	1,873,345
Due after ten years through twenty years	8,118,486
Due after twenty years	6,175,067
Mortgage-backed and asset-backed securities	119,983
Fixed maturities, fair value	$ 17,155,012	$ 17,870,206