Property and Casualty Insurance Reserves (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Property and Casulty Insurance Reserve - Gross of Reinsurance at Beginning of Year	$ 862.8	$ 733.9
Less Reinsurance Recoverables at Beginning of Year	52.0	54.9
Property and Casualty Insurance Reserves - Net of Reinsurance at Beginning of Year	810.8	679.0
Property and Casualty Insurance Reserves Acquired, Net of Reinsurance and Indemnification	0.0	125.4
Incurred Losses and LAE Related to Prior Years	(16.6)	(13.9)
Total Incurred Losses and LAE	689.6	487.3
Paid Losses and LAE Related to Prior Years	287.6	233.9
Total Paid Losses and LAE	634.3	498.0
Property and Casualty Insurance Reserves - Net of Reinsurance at End of Period	866.1	793.7
Plus Reinsurance Recoverables at End of Period	51.3	80.7
Property and Casualty Insurance Reserves - Gross of Reinsurance at End of Period	917.4	874.4
Continuing Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Current Year	706.2	501.2
Incurred Losses and LAE Related to Prior Years	(16.5)	(10.4)
Paid Losses and LAE Related to Current Year	346.7	264.1
Paid Losses and LAE Related to Prior Years	283.4	230.2
Discontinued Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(0.1)	(3.5)
Paid Losses and LAE Related to Prior Years	4.2	3.7
Personal Automobile [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	5.7	(6.4)
Homeowners [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(14.0)	(4.6)
Other Personal Lines [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(4.1)	1.4
Property and Casualty, Personal Insurance Product Line [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(12.4)	(9.5)
Property and Casualty, Commercial Insurance Product Line [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(4.2)	(4.4)
Property and Casualty, Commercial Insurance Product Line [Member] | Continuing Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(4.1)	(0.9)
Property and Casualty, Commercial Insurance Product Line [Member] | Discontinued Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	(0.1)	$ (3.5)
Catastrophe [Member] | Homeowners [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Prior Years	$ (10.8)