Investments (Amortized Cost and Fair Value of Fixed Maturities by Contractual Maturities) (Details) - USD ($) $ in Millions	Dec. 31, 2024		Dec. 31, 2023
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis	$ 1,730
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis	13,226
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis	13,555
Debt Securities, Available-for-sale, Allocated and Single Maturity Date, Maturity, after 10 Years, Amortized Cost	45,443
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Amortized Cost	8,953
Available for Sale at Fair value - Amortized cost	82,907		$ 64,977
Available-for-sale Securities, Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value	1,747
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value	13,177
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value	13,233
Debt Securities, Available-for-sale, Maturity, Allocated and Single Maturity Date, after 10 Years, Fair Value	40,836
Debt Securities, Available-for-sale, Maturity, without Single Maturity Date, Fair Value	8,624
Fixed maturity securities available-for-sale	$ 77,617	[1]	$ 60,467	[2]

[1] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of December 31, 2024, the fair value of such investments was $966 million

[2] Excludes limited partnerships that are measured at estimated fair value using the NAV per share (or its equivalent) as a practical expedient. As of December 31, 2023, the fair value of such investments was $856 million.