|**Stockholders' Equity and Statutory Accounting Practices (Tables)**   | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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|**Stockholders' Equity and Statutory Accounting Practices [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Combined statutory capital and surplus and net income (loss)           | Statutory InformationStatutory Capital and SurplusStatutory Net Income (Loss)December 31Years ended December 31(In millions)2012 (b)20112012 (b)20112010Combined Continental Casualty Companies (a)$9,998$9,888$391$954$258Life company556519442986________________(a)Represents the combined statutory surplus of CCC and its subsidiaries, including the life company.(b)Information derived from the statutory-basis financial statements to be filed with insurance regulators.
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|                                                                       | Statutory Capital and Surplus                                                                                                                                                                                                                                                                                                                                                                                                                                                      
|                                                                       | December 31                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|(In millions)                                                          | 2012 (b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|Combined Continental Casualty Companies (a)                            | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Life company                                                           | 556                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|(a)                                                                    | Represents the combined statutory surplus of CCC and its subsidiaries, including the life company.                                                                                                                                                                                                                                                                                                                                                                                 
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|(b)                                                                    | Information derived from the statutory-basis financial statements to be filed with insurance regulators.                                                                                                                                                                                                                                                                                                                                                                           

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