Condensed Consolidated Statements of Financial Position (unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Statement of Financial Position [Abstract]
Fixed income securities, at fair value, amortized cost	$ 59,338	$ 58,730
Equity securities, at fair value, cost	10,354	8,026
Short-term, at fair value, amortized cost	$ 4,707	$ 4,888
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)	82,000.0	82,000.0
Preferred stock, shares outstanding (in shares)	82,000.0	82,000.0
Preferred stock, value aggregate liquidation preference	$ 2,050	$ 2,050
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)	258,000,000	260,000,000
Treasury stock, shares (in shares)	642,000,000	640,000,000