Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale securities, at fair value:
Fixed maturity securities (amortized cost)	$ 84,287	$ 81,993
Variable interest entities' fixed maturity securities (amortized cost)	200	596
Equity securities (cost)	$ 260	$ 226
Stockholders Equity
Preferred stock - shares authorized (in shares)	10,000,000	10,000,000
Common stock - shares authorized (in shares)	800,000,000	800,000,000
Common stock - shares issued (in shares)	226,335,105	243,835,893
Common stock - shares outstanding (in shares)	226,335,105	243,835,893