Schedule 3 - Supplementary Insurance Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Supplementary Insurance Information, by Segment [Line Items]
Premiums	$ 1,862.2		$ 2,025.8		$ 2,107.1
Other Income	1.4		0.8		0.8
Net Investment Income	309.1		314.7		295.9
Insurance Claims and Policyholders' Benefits	1,261.7		1,357.2		1,582.0
Amortization of Deferred Policy Acquisition Costs	235.4		253.9		257.0
Other Insurance Expenses	393.0		400.5		415.3
Deferred Policy Acquisition Costs	303.3		302.9
Insurance Reserves	4,007.6		4,061.0
Unearned Premiums	536.9		598.9
Property and Casualty Insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums	1,249.5		1,392.9		1,467.2
Premiums Written	1,189.1		1,342.2		1,454.1
Other Income	0.5		0.5		0.7
Net Investment Income	72.7		90.9		77.9
Insurance Claims and Policyholders' Benefits	887.3		969.3		1,188.9
Amortization of Deferred Policy Acquisition Costs	187.5		207.2		212.6
Other Insurance Expenses	166.2		168.2		179.9
Deferred Policy Acquisition Costs	78.2		85.7
Insurance Reserves	651.1		742.6
Unearned Premiums	509.7		570.3
Life and Health Insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums	612.7	[1]	632.9	[1]	639.9	[1]
Other Income	0.9	[1]	0.2	[1]	0.1	[1]
Net Investment Income	218.7	[1]	209.9	[1]	204.3	[1]
Insurance Claims and Policyholders' Benefits	374.4	[1]	387.9	[1]	393.1	[1]
Amortization of Deferred Policy Acquisition Costs	47.9	[1]	46.7	[1]	44.4	[1]
Other Insurance Expenses	268.1	[1]	271.5	[1]	266.4	[1]
Deferred Policy Acquisition Costs	225.1	[1]	217.2	[1]
Insurance Reserves	3,278.2	[1]	3,222.8	[1]
Unearned Premiums	27.2	[1]	28.6	[1]
Other Segments [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums	0		0		0
Other Income	0		0.1		0
Net Investment Income	17.7		13.9		13.7
Insurance Claims and Policyholders' Benefits	0		0		0
Amortization of Deferred Policy Acquisition Costs	0		0		0
Other Insurance Expenses	(41.3)		(39.2)		(31.0)
Deferred Policy Acquisition Costs	0		0
Insurance Reserves	78.3		95.6
Unearned Premiums	$ 0		$ 0

[1] The Company’s Life & Health Insurance employee-agents also market certain property and casualty insurance products under common management. Accordingly, the Company includes the results of these property and casualty insurance products in its Life & Health Insurance segment.