Property and Casualty Insurance Reserves (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items]
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	$ 1,010.2	$ 964.6
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Property and Casulty Insurance Reserve - Gross of Reinsurance at Beginning of Year	1,118.7	1,211.3
Less Reinsurance Recoverables at Beginning of Year	78.1	77.4
Property and Casualty Insurance Reserves - Net of Reinsurance at Beginning of Year	1,040.6	1,133.9
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	(28.2)	(19.1)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	422.0	457.8
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	1,058.7	1,036.8
Property and Casualty Insurance Reserves - Gross of Reinsurance at End of Period	1,063.6	1,131.4
Plus Reinsurance Recoverabe at End of Period	71.5	69.7
Property and Casualty Insurance Reserves - Net of Reinsurance at End of Period	992.1	1,061.7
Personal Lines [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	(27.6)	(19.2)
Commercial Lines [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	(0.6)	0.1
Segment, Continuing Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Incurred Losses and LAE Related to Current Year	1,038.4	983.7
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	(30.1)	(19.5)
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	636.7	579.0
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	399.9	425.3
Segment, Discontinued Operations [Member]
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims, Prior Years	1.9	0.4
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	$ 22.1	$ 32.5