Investments (Contractual Maturity Dates For Fixed-Maturity And Short-Term Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Amortized cost
Due in one year or less	$ 973
Due after one year through five years	4,407
Due after five years through ten years	3,592
Due after ten years	5,389
Total	14,361	$ 12,979
Fair value
Due in one year or less	964
Due after one year through five years	4,304
Due after five years through ten years	3,474
Due after ten years	5,049
Total	$ 13,791	$ 12,132
% of fair value
Due in one year or less	7.00%
Due after one year through five years	31.20%
Due after five years through ten years	25.20%
Due after ten years	36.60%
Total	100.00%