Investments - Schedule of Fixed Maturities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Amortized Cost, net
Due in one year or less	$ 169,491
Due after one year through five years	1,113,684
Due after five years through ten years	1,691,785
Due after ten years through twenty years	7,976,112
Due after twenty years	7,418,120
Mortgage-backed and asset-backed securities	124,744
Fixed maturities, net of allowance for credit losses	18,493,936
Fair Value
Due in one year or less	170,003
Due after one year through five years	1,118,421
Due after five years through ten years	1,717,908
Due after ten years through twenty years	7,740,695
Due after twenty years	6,333,344
Mortgage-backed and asset-backed securities	126,514
Fixed maturities, fair value	$ 17,206,885	$ 16,503,365