CONSOLIDATED STATEMENTS OF FINANCIAL POSITION (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Fixed income securities, at fair value, amortized cost (in dollars)	$ 57,201	$ 59,672
Equity securities, at fair value, cost (in dollars)	4,806	3,692
Short-term, at fair value, amortized cost (in dollars)	$ 2,122	$ 2,540
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	72,200	72,200
Preferred stock, shares outstanding	72,200	72,200
Preferred stock, shares aggregate liquidation preference (in dollars)	$ 1,805	$ 1,805
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,000,000,000	2,000,000,000
Common stock, shares issued	900,000,000	900,000,000
Common stock, shares outstanding	381,000,000	418,000,000
Treasury stock, shares	519,000,000	482,000,000