| **Reinsurance (Tables)**                                                                               | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
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| **Reinsurance Disclosures [Abstract]**                                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| Earned Consolidated Property Casualty Insurance Premiums On Assumed And Ceded Business                 | Our condensed consolidated statements of income include earned consolidated property casualty insurance premiums on assumed and ceded business: (Dollars in millions) Three months ended September 30, Nine months ended September 30,  2015 2014 2015 2014Direct earned premiums $1,110 $1,067 $3,279 $3,134Assumed earned premiums 3 3 8 8Ceded earned premiums (37) (45) (111) (132)Earned premiums $1,076 $1,025 $3,176 $3,010                                                                         |
| Incurred Consolidated Property Casualty Insurance Loss And Loss Expenses On Assumed And Ceded Business | Our condensed consolidated statements of income include incurred consolidated property casualty insurance loss and loss expenses on assumed and ceded business:(Dollars in millions) Three months ended September 30, Nine months ended September 30,  2015 2014 2015 2014Direct incurred loss and loss expenses $618 $633 $1,984 $2,026Assumed incurred loss and loss expenses 2 1 2 5Ceded incurred loss and loss expenses (7) (12) (30) (26)Incurred loss and loss expenses $613 $622 $1,956 $2,005          |
| Earned Life Insurance Premiums On Ceded Business                                                       | Our condensed consolidated statements of income include earned life insurance premiums on ceded business: (Dollars in millions) Three months ended September 30, Nine months ended September 30,  2015 2014 2015 2014Direct earned premiums $67 $61 $200 $191Ceded earned premiums (16) (15) (44) (44)Earned premiums $51 $46 $156 $147                                                                                                                                                                                   |
| Life Insurance Contract Holders' Benefits Incurred On Ceded Business                                   | Our condensed consolidated statements of income include life insurance contract holders' benefits incurred on ceded business: (Dollars in millions) Three months ended September 30, Nine months ended September 30,  2015 2014 2015 2014Direct contract holders' benefits incurred $70 $80 $214 $228Ceded contract holders' benefits incurred (13) (16) (39) (52)Contract holders' benefits incurred $57 $64 $175 $176                                                                                                   |

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Life Insurance Contract Holders' Benefits Incurred On Ceded Business
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