Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2012 Series A Preferred Stock [Member]
Available-for-sale securities, at fair value:
Fixed maturity securities (amortized cost)	$ 75,856	$ 72,718
Variable interest entities' fixed maturity securities (amortized cost)	681	677
Equity securities (cost)	$ 166	$ 137
Stockholders Equity
Preferred stock - shares authorized (in shares)	10,000,000	10,000,000
Series A preferred stock - shares issued (in shares)			9,532
Series A preferred stock - shares outstanding (in shares)			9,532
Common stock - shares authorized (in shares)	800,000,000	800,000,000
Common stock - shares issued (in shares)	262,342,363	271,402,586
Common stock - shares outstanding (in shares)	262,342,363	271,402,586