Condensed Consolidated Balance Sheets - (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Statement of Financial Position [Abstract]
Fixed maturities securities at amortized cost	$ 40,342	$ 38,953
Marketable securities fixed maturities allowance for credit loss	31	40
Equity securities at cost	976	941
Mortgage loans on real estate commercial and consumer allowance for credit loss	26	26
Allowance for uncollectible reinsurance	21	21
Allowance for uncollectible insurance receivables	30	33
Accumulated depreciation on property and equipment	257	231
Due to related parties	$ 31	$ 89
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)	271,356,177	271,391,603
Treasury stock, shares (in shares)	1,684,066	1,648,640