Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 35,955	$ 35,836
Fixed maturities, allowance for credit losses	7	0
Equity securities, cost	142	196
Mortgage loans on real estate valuation allowance	0	1
Securities pledged, amortized costs	1,416	1,264
Preferred stock, aggregate liquidation preference	$ 625	$ 625
Preferred stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	900,000,000	900,000,000
Common stock, shares issued	142,899,061	140,726,677
Common stock, shares outstanding	126,127,821	132,325,790
Treasury stock, shares	16,771,240	8,400,887
Common stock, par value	$ 0.01	$ 0.01