v2.4.0.6
Discontinued Operations (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Dec. 31, 2011
Dec. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]        
Interest, Loan Fees and Earned Discounts $ 0 $ 15.4    
Other Income 0 0.1    
Net Gain on Sale of Loans in Inactive Portfolio 11.3 0    
Net Investment Income 0 0.4    
Net Realized Gains on Sales of Investments 0 0.3    
Total Revenues Included in Discontinued Operations 11.3 16.2    
Income (Loss) from Discontinued Operations before Income Taxes:        
Net Gain on Sale of Loans in Inactive Portfolio 11.3 0    
Income from Discontinued Operations before Income Taxes 12.3 9.4    
Income Tax Expense (5.0) (2.9)    
Income from Discontinued Operations 7.3 6.5    
Income from Discontinued Operations Per Unrestricted Share [Abstract]        
Basic (in dollars per share) $ 0.12 $ 0.11    
Diluted (in dollars per share) $ 0.12 $ 0.11    
Property and Casualty 1,001.4 1,095.8 1,029.1 1,118.7
Fireside [Member]
       
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]        
Net Gain on Sale of Loans in Inactive Portfolio 11.3 0    
Income (Loss) from Discontinued Operations before Income Taxes:        
Results of Operations / Change in Estimate of Retained Liabilities Arising from Discontinued Operations (0.2) 12.0    
Net Gain on Sale of Loans in Inactive Portfolio 11.3 0    
Income from Discontinued Operations Per Unrestricted Share [Abstract]        
Notional Amount of Sales of Loans Held-for-sale 283      
Disposal Group, Including Discontinued Operation, Transaction Costs 14.9      
Disposal Group, Including Discontinued Operation, Accrued Transaction Costs 8.7      
Unitrin Business Insurance [Member]
       
Income (Loss) from Discontinued Operations before Income Taxes:        
Results of Operations / Change in Estimate of Retained Liabilities Arising from Discontinued Operations 1.2 (2.6)    
Income from Discontinued Operations Per Unrestricted Share [Abstract]        
Property and Casualty $ 117.3   $ 125.6