Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Fixed maturities securities at amortized cost	$ 38,953	$ 38,126
Marketable securities fixed maturities allowance for credit loss	40	0
Equity securities at cost	941	820
Mortgage loans on real estate commercial and consumer allowance for credit loss	26	0
Allowance for uncollectible reinsurance	21	25
Allowance for uncollectible insurance receivables	33	32
Accumulated depreciation on property and equipment	231	215
Due from related parties	0	21
Due to related parties	$ 89	$ 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)	271,391,603	271,412,591
Treasury stock, shares (in shares)	1,648,640	1,627,652