Investments - (Narrative) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) security	Dec. 31, 2023 USD ($) security
Investments [Abstract]
Equity Securities at Fair Value	$ 11,557	$ 10,989
Fair value of largest single common stock holding	$ 942	$ 842
Largest equity holdings to total equity portfolio	8.40%	7.90%
Largest equity holdings to total investment portfolio	3.70%	3.40%
Allowance for credit loss on fixed-maturity	$ 27	$ 18
Number of fixed-maturity securities in a total unrealized loss position | security	3,329	2,840
Fixed-maturity securities, total unrealized loss	$ 714	$ 687
Number of fixed-maturity securities in continuous unrealized loss position and below 70 percent of amortized cost	12	20
Fixed maturity investments, Percentage of amortized costs	70.00%