Condensed Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities securities at amortized cost	$ 38,034	$ 38,126
Marketable securities, fixed maturities, amortized cost	49	0
Equity securities at cost	936	820
Mortgage loans on real estate, commercial and consumer, allowance for credit loss	20	0
Allowance for uncollectible reinsurance	23	25
Allowance for uncollectible insurance receivables	30	32
Accumulated depreciation on property and equipment	224	215
Due to related parties	7	21
Due from related parties	$ 15	$ 21
Common stock, par value (in usd per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	273,040,243	273,040,243
Common stock, shares outstanding (in shares)	271,370,988	271,412,591
Treasury stock, shares (in shares)	1,669,255	1,627,652