Investments (Unrealized Losses) (Details)	Dec. 31, 2012 securities
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Other-than-temporarily impaired securities, number of securities rated investment grade	2
Equity Securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	13
Other-than-temporarily impaired securities, number of securities rated investment grade	5
Debt securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of issues	72
Gross unrealized losses, percentage of total debt	5.90%
Gross unrealized losses, market value as a percent of amortized cost	98.20%
Gross unrealized losses, number of securities with maturities of 12 months or greater	15
Gross unrealized losses, number of securities with maturities of 12 months or greater (as a percentage)	20.50%
Debt securities [Member] | Investment Grade [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	65
U.S. Treasury [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	0
U.S. Agencies [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	0
States and Political Subdivisions [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	11
States and Political Subdivisions [Member] | A Minus Rating or Above [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	10
States and Political Subdivisions [Member] | BBB Plus [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	1
Foreign Governments [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	0
Public Utilities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	8
Public Utilities [Member] | BBB or Above [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	7
Public Utilities [Member] | BB Plus [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	1
Corporate [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	44
Corporate [Member] | Below Investment Grade [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	4
Mortgage-backed [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	3
Mortgage-backed [Member] | AA Plus Rating [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	2
Mortgage-backed [Member] | CCC Rating [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	1
Home Equity [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	6
Home Equity [Member] | BBB or Above [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	5
Home Equity [Member] | CC Rating [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	1
Manufactured Housing [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	0