Business Segments - Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 segments	Sep. 30, 2011
Segment Reporting Information [Line Items]
Number of Operating Segments			4
Earned Premiums	$ 527.3	$ 543.0	$ 1,586.3	$ 1,637.1
Net Investment Income	70.4	58.6	223.0	222.7
Other Income	0.2	0.4	0.6	0.8
Total Revenues	645.6	592.8	1,865.7	1,881.7
Net Realized Gains (Losses) on Sales of Investments	50.9	(4.2)	59.9	27.8
Net Impairment Losses Recognized in Earnings	(3.2)	(5.0)	(4.1)	(6.7)
Segment Operating Profit (Loss)	33.8	4.2	72.6	16.1
Income (Loss) from Continuing Operations before Income Taxes	81.5	(5.0)	128.4	37.2
Segment Net Operating Income (Loss)	24.6	7.1	57.2	23.0
Income from Continuing Operations	55.6	1.1	93.5	36.7
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	594.3	600.6	1,799.1	1,854.1
Segment Operating Profit (Loss)	44.6	17.1	102.7	47.4
Segment Net Operating Income (Loss)	31.8	15.4	76.3	42.4
Kemper Preferred [Member]
Segment Reporting Information [Line Items]
Earned Premiums	222.9	216.5	655.9	642.8
Net Investment Income	10.8	8.2	33.6	37.8
Other Income	0.1	0.1	0.3	0.2
Total Revenues	233.8	224.8	689.8	680.8
Segment Operating Profit (Loss)	10.4	(16.1)	4.4	(56.5)
Segment Net Operating Income (Loss)	8.4	(8.3)	8.5	(30.3)
Kemper Specialty [Member]
Segment Reporting Information [Line Items]
Earned Premiums	103.9	111.0	317.3	336.7
Net Investment Income	4.5	3.7	14.4	17.5
Other Income	0.1	0.2	0.2	0.4
Total Revenues	108.5	114.9	331.9	354.6
Segment Operating Profit (Loss)	3.2	7.1	2.5	18.9
Segment Net Operating Income (Loss)	2.7	5.7	4.0	15.4
Kemper Direct [Member]
Segment Reporting Information [Line Items]
Earned Premiums	40.3	54.4	131.2	171.8
Net Investment Income	3.4	2.8	10.7	13.6
Other Income	0	0.1	0	0.1
Total Revenues	43.7	57.3	141.9	185.5
Segment Operating Profit (Loss)	1.6	(3.8)	(6.9)	(19.6)
Segment Net Operating Income (Loss)	1.5	(1.7)	(2.7)	(10.4)
Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	160.2	161.1	481.9	485.8
Net Investment Income	48.1	42.5	153.5	147.3
Other Income	0	0	0.1	0.1
Total Revenues	208.3	203.6	635.5	633.2
Segment Operating Profit (Loss)	29.4	29.9	102.7	104.6
Segment Net Operating Income (Loss)	19.2	19.7	66.5	67.7
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Other Income	3.6	1.4	10.8	6.5
Segment Operating Profit (Loss)	(10.8)	(12.9)	(30.1)	(31.3)
Segment Net Operating Income (Loss)	(7.2)	(8.3)	(19.1)	(19.4)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	33.0	(2.7)	38.9	18.0
Net Impairment Losses Recognized in Earnings, Net of Tax	$ (2.0)	$ (3.3)	$ (2.6)	$ (4.3)