Schedule 3 - Supplementary Insurance Information (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplementary Insurance Information, by Segment [Line Items]
Premiums		$ 2,009.6	$ 1,862.2	$ 2,025.8
Other Income		3.7	1.4	0.8
Net Investment Income		302.6	309.1	314.7
Insurance Claims and Policyholders' Benefits		1,467.5	1,261.7	1,357.2
Amortization of Deferred Policy Acquisition Costs		257.4	235.4	253.9
Other Insurance Expenses		387.8	393.0	400.5
Deferred Policy Acquisition Costs		316.4	303.3
Insurance Reserves		4,203.8	4,007.6
Unearned Premiums		613.1	536.9
Property and Casualty Insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums		1,415.2	1,249.5	1,392.9
Premiums Written		1,406.2	1,189.1	1,342.2
Other Income		0.6	0.5	0.5
Net Investment Income		73.3	72.7	90.9
Insurance Claims and Policyholders' Benefits		1,086.2	887.3	969.3
Amortization of Deferred Policy Acquisition Costs		213.1	187.5	207.2
Other Insurance Expenses		155.0	166.2	168.2
Deferred Policy Acquisition Costs		80.7	78.2
Insurance Reserves		800.5	651.1
Unearned Premiums		586.1	509.7
Life and Health Insurance [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums	[1]	594.4	612.7	632.9
Other Income	[1]	2.4	0.9	0.2
Net Investment Income	[1]	214.2	218.7	209.9
Insurance Claims and Policyholders' Benefits	[1]	381.3	374.4	387.9
Amortization of Deferred Policy Acquisition Costs	[1]	44.3	47.9	46.7
Other Insurance Expenses	[1]	275.7	268.1	271.5
Deferred Policy Acquisition Costs	[1]	235.7	225.1
Insurance Reserves	[1]	3,346.2	3,278.2
Unearned Premiums	[1]	27.0	27.2
Other Segments [Member]
Supplementary Insurance Information, by Segment [Line Items]
Premiums		0.0	0.0	0.0
Other Income		0.7	0.0	0.1
Net Investment Income		15.1	17.7	13.9
Insurance Claims and Policyholders' Benefits		0.0	0.0	0.0
Amortization of Deferred Policy Acquisition Costs		0.0	0.0	0.0
Other Insurance Expenses		(42.9)	(41.3)	$ (39.2)
Deferred Policy Acquisition Costs		0.0	0.0
Insurance Reserves		57.1	78.3
Unearned Premiums		$ 0.0	$ 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.