Investments (Unrealized Losses) (Details) - Jun. 30, 2015 $ in Millions	USD ($) security
Asset-Backed Security [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Securities, other-than-temporarily impaired | $	$ 0.1
Debt Securities [Member]
Available-for-Sale Securities and Held-to-Maturity Securities [Line Items]
Gross unrealized losses, number of issues	364
Gross unrealized losses, percentage of total debt	27.30%
Gross unrealized losses, market value as a percent of amortized cost	97.50%
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)	21.20%
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	361