Investments (Unrealized Losses) (Details)	3 Months Ended
	Mar. 31, 2015 security
Asset-Backed Security [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Securities, other-than-temporarily impaired	0
Debt Securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of issues	109
Gross unrealized losses, percentage of total debt	8.20%
Gross unrealized losses, market value as a percent of amortized cost	98.50%
Gross unrealized losses, number of securities with maturities of 12 months or greater	77
Gross unrealized losses, number of securities with maturities of 12 months or greater (as a percentage)	70.60%
Equity Securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	23
External Credit Rating, Investment Grade [Member] | Debt Securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of securities rated investment grade	106