Investments (Details 14) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Municipal Bonds
Threshold percentage of municipal to total carrying value	5.00%	5.00%
Securities loaned
Fixed income and equity securities loaned	$ 312,000,000	$ 525,000,000
Interest Income on collateral, net of fees	1,000,000	1,000,000	1,000,000
Other investment information
Below investment grade assets	2,890,000,000	3,350,000,000
Fixed income securities and short-term investments deposited with regulatory authorities	53,000,000
Non-income producing fixed income securities and other investments	$ 11,000,000
Shareholders' equity | Concentration of credit risk | Minimum
Municipal Bonds
Percentage of credit concentration risk of single issuer and affiliates of shareholder's equity	10.00%
California
Municipal Bonds
Percentage of municipal bonds carrying value	15.90%	14.10%
Texas
Municipal Bonds
Percentage of municipal bonds carrying value	13.50%	11.80%
Oregon
Municipal Bonds
Percentage of municipal bonds carrying value	5.40%	4.70%
New Jersey
Municipal Bonds
Percentage of municipal bonds carrying value	5.20%	4.50%
New York
Municipal Bonds
Percentage of municipal bonds carrying value	5.20%	7.10%
Illinois
Municipal Bonds
Percentage of municipal bonds carrying value	5.10%	4.30%