Business Segments - Segment Revenues (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Earned Premiums	$ 520.8	$ 527.3	$ 529.8	$ 529.2	$ 536.5	$ 543.0	$ 548.1	$ 546.0	$ 2,107.1	$ 2,173.6	$ 2,289.4
Net Investment Income	72.9	70.4	75.2	77.4	75.3	58.6	82.9	81.2	295.9	298.0	325.7
Other Income	0.2	0.2	0.2	0.2	0.2	0.4	0.2	0.2	0.8	1.0	1.3
Total Revenues	596.6	645.6	608.9	611.2	613.3	592.8	647.7	641.2	2,462.3	2,495.0	2,642.5
Net Realized Gains on Sales of Investments	5.5	50.9	4.1	4.9	5.9	(4.2)	17.8	14.2	65.4	33.7	42.6
Net Impairment Losses Recognized in Earnings	(2.8)	(3.2)	(0.4)	(0.5)	(4.6)	(5.0)	(1.3)	(0.4)	(6.9)	(11.3)	(16.5)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues									2,390.1	2,464.1	2,605.5
Kemper Preferred [Member]
Segment Reporting Information [Line Items]
Earned Premiums									879.4	859.8	888.0
Net Investment Income									45.0	48.8	55.4
Other Income									0.4	0.3	0.4
Total Revenues									924.8	908.9	943.8
Kemper Specialty [Member]
Segment Reporting Information [Line Items]
Earned Premiums									419.8	445.2	474.9
Net Investment Income									19.0	22.8	25.8
Other Income									0.3	0.5	0.6
Total Revenues									439.1	468.5	501.3
Kemper Direct [Member]
Segment Reporting Information [Line Items]
Earned Premiums									168.0	222.7	282.4
Net Investment Income									13.9	17.4	20.6
Other Income									0	0.1	0.1
Total Revenues									181.9	240.2	303.1
Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums									639.9	645.9	644.1
Net Investment Income									204.3	200.5	213.0
Other Income									0.1	0.1	0.2
Total Revenues									844.3	846.5	857.3
Unallocated Amount to Segment [Member]
Segment Reporting Information [Line Items]
Other Income									$ 13.7	$ 8.5	$ 10.9