Business Segments - Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 segments	Jun. 30, 2013
Segment Reporting Information [Line Items]
Number of Operating Segments			2
Earned Premiums	$ 470.3	$ 512.8	$ 947.9	$ 1,022.7
Net Investment Income	72.6	74.6	143.7	155.4
Other Income	0.2	0.2	0.3	0.4
Total Revenues	542.5	588.9	1,097.1	1,204.8
Net Realized Gains on Sales of Investments	3.5	2.3	10.1	29.2
Segment Operating Profit (Loss)	11.8	45.1	57.9	104.7
Net Impairment Losses Recognized in Earnings	(4.1)	(1.0)	(4.9)	(2.9)
Income from Continuing Operations before Income Taxes	11.2	46.4	63.1	131.0
Segment Net Operating Income (Loss)	9.6	31.7	41.1	74.0
Income from Continuing Operations	9.3	32.5	44.5	91.1
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment Operating Profit (Loss)	(8.6)	(11.7)	(16.4)	(24.2)
Segment Net Operating Income (Loss)	(5.1)	(7.7)	(10.1)	(15.6)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other Income	5.1	3.3	8.4	6.0
Net Realized Gains on Sales of Investments	3.5	2.3	10.1	29.2
Net Impairment Losses Recognized in Earnings	(4.1)	(1.0)	(4.9)	(2.9)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	2.4	1.5	6.6	19.0
Net Impairment Losses Recognized in Earnings, Net of Tax	(2.7)	(0.7)	(3.2)	(1.9)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	538.0	584.3	1,083.5	1,172.5
Segment Operating Profit (Loss)	20.4	56.8	74.3	128.9
Segment Net Operating Income (Loss)	14.7	39.4	51.2	89.6
Operating Segments [Member] | Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	317.5	353.9	639.8	706.0
Net Investment Income	19.5	21.5	37.1	46.6
Other Income	0.2	0.1	0.3	0.3
Total Revenues	337.2	375.5	677.2	752.9
Segment Operating Profit (Loss)	(4.3)	25.6	15.0	65.8
Segment Net Operating Income (Loss)	(1.2)	19.1	13.2	48.1
Operating Segments [Member] | Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	152.8	158.9	308.1	316.7
Net Investment Income	48.0	49.8	98.2	102.8
Other Income	0	0.1	0	0.1
Total Revenues	200.8	208.8	406.3	419.6
Segment Operating Profit (Loss)	24.7	31.2	59.3	63.1
Segment Net Operating Income (Loss)	$ 15.9	$ 20.3	$ 38.0	$ 41.5