Investments (Contractual maturity) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Investments [Abstract]
Due in one year or less, cost or amortized cost	$ 952	$ 1,603
Due after one year through five years, cost or amortized cost	9,487	10,637
Due after five years through ten years, cost or amortized cost	14,323	13,294
Due after ten years, cost or amortized cost	16,556	14,411
Cost or Amortized Cost	41,318	39,945
Due in one year or less, estimated fair value	948	1,624
Due after one year through five years, estimated fair value	9,000	11,229
Due after five years through ten years, estimated fair value	12,765	14,338
Due after ten years, estimated fair value	14,526	17,182
Estimated Fair Value	$ 37,239	$ 44,373