Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Fixed maturities, amortized cost	$ 37,469	$ 39,426
Equity securities, cost	$ 733	$ 881
Preferred stock, par value	$ 0.10	$ 0.10
Preferred stock, shares authorized	100,000,000	100,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,800,000,000	1,800,000,000
Common stock, shares issued	372,934,540	387,210,096
Common stock, shares outstanding	372,934,540	387,210,096