Business Segments - Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 segments	Mar. 31, 2012
Segment Reporting Information [Line Items]
Number of Operating Segments	4
Earned Premiums	$ 509.9	$ 529.2
Net Investment Income	80.8	77.4
Other Income	0.2	0.2
Total Revenues	615.9	611.2
Net Realized Gains on Sales of Investments	26.9	4.9
Net Impairment Losses Recognized in Earnings	(1.9)	(0.5)
Segment Operating Profit (Loss)	59.6	46.0
Income from Continuing Operations before Income Taxes	84.6	50.4
Segment Net Operating Income (Loss)	42.3	33.4
Income from Continuing Operations	58.6	36.3
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	588.2	604.8
Segment Operating Profit (Loss)	72.1	58.0
Segment Net Operating Income (Loss)	50.2	41.0
Kemper Preferred [Member]
Segment Reporting Information [Line Items]
Earned Premiums	219.2	215.0
Net Investment Income	15.0	10.9
Other Income	0.1	0.1
Total Revenues	234.3	226.0
Segment Operating Profit (Loss)	26.4	13.1
Segment Net Operating Income (Loss)	18.8	10.4
Kemper Specialty [Member]
Segment Reporting Information [Line Items]
Earned Premiums	99.2	106.8
Net Investment Income	6.3	5.2
Other Income	0.1	0
Total Revenues	105.6	112.0
Segment Operating Profit (Loss)	4.2	4.9
Segment Net Operating Income (Loss)	3.5	4.1
Kemper Direct [Member]
Segment Reporting Information [Line Items]
Earned Premiums	33.7	47.0
Net Investment Income	3.8	3.6
Total Revenues	37.5	50.6
Segment Operating Profit (Loss)	9.6	(3.0)
Segment Net Operating Income (Loss)	6.7	(1.3)
Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	157.8	160.4
Net Investment Income	53.0	55.7
Other Income	0	0.1
Total Revenues	210.8	216.2
Segment Operating Profit (Loss)	31.9	43.0
Segment Net Operating Income (Loss)	21.2	27.8
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Income	2.7	2.0
Segment Operating Profit (Loss)	(12.5)	(12.0)
Segment Net Operating Income (Loss)	(7.9)	(7.6)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	17.5	3.2
Net Impairment Losses Recognized in Earnings, Net of Tax	$ (1.2)	$ (0.3)