Investments Investments (Details) - Contractual Maturities - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Investments [Abstract]
Fixed maturities, due in one year or less, amortized cost	$ 5,074
Fixed maturities, due after 1 year through 5 years, amortized cost	18,476
Fixed maturities, due after 5 years through 10 years, amortized cost	18,200
Fixed maturities, due after 10 years, amortized cost	24,858
Fixed maturities excluding mortgage-backed securities, collateralized mortgage obligations and pass-through securities, amortized cost	66,608
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities, amortized cost	2,222
Fixed maturities, amortized cost	68,830	$ 65,281
Fixed maturities, due in one year or less, fair value	5,127
Fixed maturities, due after 1 year through 5 years, fair value	19,660
Fixed maturities, due after 5 years through 10 years, fair value	19,936
Fixed maturities, due after 10 years, fair value	26,919
Fixed maturities excluding mortgage-backed securities, collateralized mortgage obligations and pass-through securities, fair value	71,642
Mortgage-backed securities, collateralized mortgage obligations and pass-through securities, fair value	2,361
Fixed maturities, at fair value	$ 74,003	$ 68,134