Investments - Available-for-sale Fixed Maturity Securities by Contractual Maturity (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Cost or Amortized Cost
Cost or Amortized Cost	$ 42,615	$ 41,102
Estimated Fair Value
Estimated Fair Value	40,626	37,697
Available-for-sale Fixed Maturities
Cost or Amortized Cost
Due in one year or less	1,121	1,012
Due after one year through five years	11,563	9,880
Due after five years through ten years	13,359	13,788
Due after ten years	16,371	16,352
Cost or Amortized Cost	42,414	41,032
Estimated Fair Value
Due in one year or less	1,091	1,001
Due after one year through five years	11,180	9,399
Due after five years through ten years	12,573	12,453
Due after ten years	15,581	14,774
Estimated Fair Value	$ 40,425	$ 37,627