Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Fixed maturities, available for sale at amortized cost	$ 32,749	$ 31,565
Equity securities, available for sale at cost	$ 1,475	$ 1,469
Common Stock, par value (USD per share)	$ 0	$ 0
Common Stock, shares authorized	200,000,000	200,000,000
Common Stock, shares outstanding	86,966,290	87,474,452