Investments - Available-for-sale Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2025	Dec. 31, 2024
Cost or Amortized Cost
Cost or Amortized Cost	$ 45,338	$ 44,196
Estimated Fair Value
Estimated Fair Value	44,116	41,827
Available-for-sale Fixed Maturities
Cost or Amortized Cost
Due in one year or less	1,275	1,761
Due after one year through five years	11,741	11,678
Due after five years through ten years	12,959	13,083
Due after ten years	18,883	16,908
Cost or Amortized Cost	44,858	43,430
Estimated Fair Value
Due in one year or less	1,267	1,753
Due after one year through five years	11,578	11,403
Due after five years through ten years	12,713	12,365
Due after ten years	18,078	15,540
Estimated Fair Value	$ 43,636	$ 41,061