Business Segments - Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 segments	Mar. 31, 2013
Segment Reporting Information [Line Items]
Number of Operating Segments	2
Earned Premiums	$ 477.6	$ 509.9
Net Investment Income	71.1	80.8
Other Income	0.1	0.2
Total Revenues	554.6	615.9
Net Realized Gains on Sales of Investments	6.6	26.9
Segment Operating Profit (Loss)	46.1	59.6
Net Impairment Losses Recognized in Earnings	(0.8)	(1.9)
Income from Continuing Operations before Income Taxes	51.9	84.6
Segment Net Operating Income (Loss)	31.5	42.3
Income from Continuing Operations	35.2	58.6
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	545.5	588.2
Segment Operating Profit (Loss)	53.9	72.1
Segment Net Operating Income (Loss)	36.5	50.2
Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	322.3	352.1
Net Investment Income	17.6	25.1
Other Income	0.1	0.2
Total Revenues	340.0	377.4
Segment Operating Profit (Loss)	19.3	40.2
Segment Net Operating Income (Loss)	14.4	29.0
Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	155.3	157.8
Net Investment Income	50.2	53.0
Total Revenues	205.5	210.8
Segment Operating Profit (Loss)	34.6	31.9
Segment Net Operating Income (Loss)	22.1	21.2
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Income	3.3	2.7
Segment Operating Profit (Loss)	(7.8)	(12.5)
Segment Net Operating Income (Loss)	(5.0)	(7.9)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	4.2	17.5
Net Impairment Losses Recognized in Earnings, Net of Tax	$ (0.5)	$ (1.2)