Investments - Schedule of Fixed Maturities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Amortized Cost, net
Due in one year or less	$ 129,415
Due after one year through five years	734,757
Due after five years through ten years	1,794,742
Due after ten years through twenty years	8,908,777
Due after twenty years	7,537,335
Mortgage-backed and asset-backed securities	117,115
Fixed maturities, net of allowance for credit losses	19,222,141
Fair Value
Due in one year or less	128,402
Due after one year through five years	738,610
Due after five years through ten years	1,791,972
Due after ten years through twenty years	8,365,383
Due after twenty years	6,468,995
Mortgage-backed and asset-backed securities	119,646
Fixed maturities, fair value	$ 17,613,008	$ 17,870,206