| **Reinsurance (Tables)**                                                                               | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
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| **Reinsurance Disclosures [Abstract]**                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| Earned Consolidated Property Casualty Insurance Premiums On Assumed And Ceded Business                 | Our consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business:(In millions) Years ended December 31,  2013 2012 2011Direct earned premiums $3,903 $3,520 $3,236Assumed earned premiums 11 9 12Ceded earned premiums (201) (185) (219)Earned premiums $3,713 $3,344 $3,029                                                                                       |
| Incurred Consolidated Property Casualty Insurance Loss And Loss Expenses On Assumed And Ceded Business | Our consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:(In millions) Years ended December 31,  2013 2012 2011Direct incurred loss and loss expenses $2,323 $2,235 $2,588Assumed incurred loss and loss expenses 11 6 24Ceded incurred loss and loss expenses (33) (104) (277)Incurred loss and loss expenses $2,301 $2,137 $2,335        |
| Earned Life Insurance Premiums On Ceded Business                                                       | Our consolidated statements of income include earned life insurance premiums on ceded business:(In millions) Years ended December 31,  2013 2012 2011Direct earned premiums $248 $235 $220Ceded earned premiums (59) (57) (55)Earned premiums $189 $178 $165                                                                                                                                                                                     |
| Life Insurance Contract Holders' Benefits Incurred On Ceded Business                                   | Our consolidated statements of income include life insurance contract policyholders’ benefits incurred on ceded business:(In millions) Years ended December 31,  2013 2012 2011Direct policyholders' benefits incurred $266 $232 $232Ceded policyholders' benefits incurred (62) (47) (43)Policyholders' benefits incurred $204 $185 $189                                                                                                  |

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