Schedule II - Condensed Financial Information of Parent - Balance Sheets Parenthetical (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fixed maturities, amortized cost	$ 35,836	$ 36,268
Equity securities, cost	196	247
Preferred stock, aggregate liquidation preference	$ 625	$ 325
Preferred stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	140,726,677	272,431,745
Common stock, shares outstanding	132,325,790	150,978,184	172,000,000.0	194,600,000
Treasury stock	8,400,887	121,453,561
Common stock, par value	$ 0.01	$ 0.01
Parent Issuer
Fixed maturities, amortized cost	$ 5	$ 0
Equity securities, cost	$ 0	$ 99