|**Deferred Acquisition Costs (Tables)**                                                                               | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|**Deferred Costs [Abstract]**                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Deferred Policy Acquisition Costs And Asset Reconciliation, Including the Amortized Deferred Policy Acquisition Costs | The table below shows the deferred policy acquisition costs and asset reconciliation.(Dollars in millions)Three months ended June 30,Six months ended June 30,2015201420152014Deferred policy acquisition costs asset, beginningof period$571$564$578$565Capitalized deferred policy acquisition costs221216428422Amortized deferred policy acquisition costs(204)(202)(413)(403)Amortized shadow deferred policy acquisition costs12(7)7(13)Deferred policy acquisition costs asset, end of period$600$571$600$571
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|(Dollars in millions)                                                                                                 | Three months ended June 30,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|                                                                                                                      | 2015                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Deferred policy acquisition costs asset, beginningof period                                                           | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Capitalized deferred policy acquisition costs                                                                         | 221                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Amortized deferred policy acquisition costs                                                                           | (204                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|Amortized shadow deferred policy acquisition costs                                                                    | 12                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Deferred policy acquisition costs asset, end of period                                                                | $                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
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+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35755530&loc=d3e11264-158415
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