Investments - Impaired Loans 3 (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Impaired loans, average investment during the period	$ 83.4	$ 55.6	$ 88.8	[1]	$ 55.6	[1]
Interest income recognized on impaired loans, on an accrual basis	1.2	1.0	3.7	[1]	1.3	[1]
Interest income recognized on impaired loans, on a cash basis	1.2	1.0	3.4	[1]	1.3	[1]
Interest income recognized on troubled debt restructured loans, on an accrual basis	$ 1.1	$ 0.8	$ 3.3		$ 0.8

[1] Includes amounts for Troubled debt restructured loans.