Business Segments - Earned Premiums by Product Line (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Life	$ 97.2	$ 98.6	$ 194.8	$ 196.5
Earned Premiums, Accident and Health	36.2	40.3	75.0	80.5
Earned Premiums, Total	470.3	512.8	947.9	1,022.7
Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	323.3	360.8	651.4	720.5
Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	212.0	244.6	428.3	490.3
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	79.0	82.1	158.7	162.5
Other Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	32.3	34.1	64.4	67.7
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	$ 13.6	$ 13.1	$ 26.7	$ 25.2