Condensed Consolidated Statements of Financial Position (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020
Fixed income securities, at fair value, amortized cost (in dollars)	$ 39,437	$ 40,034
Equity securities, at fair value, cost (in dollars)	2,655	2,740
Short-term, at fair value, amortized cost (in dollars)	$ 6,017	$ 6,807
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	81,000.0	81,000.0
Preferred stock, shares outstanding (in shares)	81,000.0	81,000.0
Preferred stock, shares aggregate liquidation preference (in shares)	$ 2,025	$ 2,025
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	2,000,000,000.0	2,000,000,000.0
Common stock, shares issued (in shares)	900,000,000	900,000,000
Common stock, shares outstanding (in shares)	300,000,000	304,000,000
Treasury stock, shares (in shares)	600,000,000	596,000,000
Preferred stock additional capital paid-in
Preferred stock, par value (in dollars per share)			$ 0.01
Preferred stock, shares authorized (in shares)	8,000,000.0
Preferred stock, shares issued (in shares)	200,000.0
Preferred stock, shares outstanding (in shares)	200,000.0
Preferred stock, shares aggregate liquidation preference (in shares)	$ 200		$ 200