Investments (Maturities of Fixed Maturity Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Investments, Debt and Equity Securities [Abstract]
Amortized cost, due in one year or less	$ 4,107
Amortized cost, due after one year through five years	18,741
Amortized cost, due after five years through ten years	13,676
Amortized cost, due after ten years	28,823
Amortized cost, Structured Securities	21,511
Fixed maturity securities, amortized cost	86,858	$ 86,129
Estimated fair value, due in one year or less	4,092
Estimated fair value, due after one year through five years	18,537
Estimated fair value, due after five years through ten years	12,855
Estimated fair value, due after ten years	26,341
Estimated fair value, Structured Securities	20,575
Fixed maturity securities, estimated fair value	$ 82,400	$ 80,085