Investments - Available-for-sale Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Cost or Amortized Cost
Cost or Amortized Cost	$ 42,753	$ 41,102
Estimated Fair Value
Estimated Fair Value	38,243	37,697
Available-for-sale Fixed Maturities
Cost or Amortized Cost
Due in one year or less	1,137	1,012
Due after one year through five years	11,320	9,880
Due after five years through ten years	13,044	13,788
Due after ten years	16,863	16,352
Cost or Amortized Cost	42,364	41,032
Estimated Fair Value
Due in one year or less	1,096	1,001
Due after one year through five years	10,651	9,399
Due after five years through ten years	11,610	12,453
Due after ten years	14,497	14,774
Estimated Fair Value	$ 37,854	$ 37,627