Discontinued Operations (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Interest, Loan Fees and Earned Discounts									$ 0	$ 0	$ 31.8
Other Automobile Finance Revenues									0	0	1.4
Gain on Sale of Loan Portfolios									0	12.9	4.5
Total Automobile Finance Revenues									0	12.9	37.7
Net Investment Income									0	0	0.5
Net Realized Gains on Sales of Investments									0	0	0.4
Total Revenues Included in Discontinued Operations									0	12.9	38.6
Income (Loss) from Discontinued Operations before Income Taxes:
Gain on Sale of Loan Portfolios									0	12.9	4.5
Income from Discontinued Operations before Income Taxes									4.9	18.9	19.5
Income Tax Expense									(1.7)	(7.3)	(6.7)
Income from Discontinued Operations	0.4	1.5	1.5	(0.2)	3.6	0	0.7	7.3	3.2	11.6	12.8
Income from Discontinued Operations Per Unrestricted Share:
Basic (in dollars per share)									$ 0.06	$ 0.20	$ 0.21
Diluted (in dollars per share)									$ 0.06	$ 0.20	$ 0.21
Property and Casualty Insurance Reserves	843.5				970.6				843.5	970.6	1,029.1	1,118.7
Fireside [Member]
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Gain on Sale of Loan Portfolios									0	12.9	4.5
Income (Loss) from Discontinued Operations before Income Taxes:
Results of Operations									0	(0.2)	18.7
Gain on Sale of Loan Portfolios									0	12.9	4.5
Unitrin Business Insurance [Member]
Income (Loss) from Discontinued Operations before Income Taxes:
Results of Operations									4.9	6.2	(3.7)
Income from Discontinued Operations Per Unrestricted Share:
Property and Casualty Insurance Reserves	82.0				99.2				82.0	99.2
Active Loan Portfolio [Member] | Fireside [Member]
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Gain on Sale of Loan Portfolios											4.5
Income (Loss) from Discontinued Operations before Income Taxes:
Gain on Sale of Loan Portfolios											4.5
Inactive Loan Portfolio [Member] | Fireside [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Notional Amount of Sales of Loans Held-for-sale										283
Disposal Group, Including Discontinued Operation, Transaction, Shutdown, and Other Costs										13.3
Disposal Group, Including Discontinued Operation, Accrued Transaction, Shutdown, and Other Costs	1.0								1.0
Discontinued Operation, Income (Loss) from Discontinued Operation Disclosures [Abstract]
Gain on Sale of Loan Portfolios										12.9
Income (Loss) from Discontinued Operations before Income Taxes:
Gain on Sale of Loan Portfolios										$ 12.9