Business Segments - Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) segments	Mar. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segments	2
Earned Premiums	$ 546.0	$ 431.3
Net Investment Income	67.0	70.6
Other Income	0.8	0.9
Total Revenues	611.3	499.2
Net Realized Gains on Sales of Investments	6.8	3.4
Segment Operating Profit (Loss)	(4.0)	30.5
Net Impairment Losses Recognized in Earnings	(9.3)	(7.0)
Loss from Early Extinguishment of Debt	0.0	9.1
Income (Loss) from Continuing Operations before Income Taxes	(6.5)	17.8
Segment Net Operating Income (Loss)	(0.6)	21.8
Income from Continuing Operations	(2.2)	13.5
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment Operating Profit (Loss)	(12.2)	(12.3)
Segment Net Operating Income (Loss)	(7.8)	(7.7)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other Income	0.1	5.2
Net Realized Gains on Sales of Investments	6.8	3.4
Net Impairment Losses Recognized in Earnings	(9.3)	(7.0)
Loss from Early Extinguishment of Debt	0.0	(9.1)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	4.4	2.2
Net Impairment Losses Recognized in Earnings, Net of Tax	(6.0)	(4.6)
Loss from Early Extinguishment of Debt, Net of Tax	0.0	(5.9)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	613.7	497.6
Segment Operating Profit (Loss)	8.2	42.8
Segment Net Operating Income (Loss)	7.2	29.5
Operating Segments [Member] | Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	396.2	287.6
Net Investment Income	11.9	14.8
Other Income	0.2	0.3
Total Revenues	408.3	302.7
Segment Operating Profit (Loss)	(22.8)	18.0
Segment Net Operating Income (Loss)	(13.1)	13.4
Operating Segments [Member] | Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	149.8	143.7
Net Investment Income	55.0	50.4
Other Income	0.6	0.8
Total Revenues	205.4	194.9
Segment Operating Profit (Loss)	31.0	24.8
Segment Net Operating Income (Loss)	$ 20.3	$ 16.1