|**Property Casualty Loss And Loss Expenses (Tables)**         | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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|**Insurance [Abstract]**                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Consolidated Property Casualty Loss And Loss Expense Reserves | This table summarizes activity for our consolidated property casualty loss and loss expense reserves:(Dollars in millions)Years ended December 31,201420132012Gross loss and loss expense reserves, January 1$4,241$4,169$4,280Less reinsurance recoverable299356375Net loss and loss expense reserves, January 13,9423,8133,905Net incurred loss and loss expenses related to:Current accident year2,7252,4482,533Prior accident years(98)(147)(396)Total incurred2,6272,3012,137Net paid loss and loss expenses related to:Current accident year1,2121,0451,123Prior accident years1,2011,1271,106Total paid2,4132,1722,229Net loss and loss expense reserves, December 314,1563,9423,813Plus reinsurance recoverable282299356Gross loss and loss expense reserves, December 31$4,438$4,241$4,169
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|(Dollars in millions)                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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|Gross loss and loss expense reserves, January 1               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Less reinsurance recoverable                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Net loss and loss expense reserves, January 1                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Net incurred loss and loss expenses related to:               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Current accident year                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Prior accident years                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Total incurred                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Net paid loss and loss expenses related to:                   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Current accident year                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Prior accident years                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Total paid                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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|Net loss and loss expense reserves, December 31               |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Plus reinsurance recoverable                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Gross loss and loss expense reserves, December 31             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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                    duration X- DefinitionTabular disclosure of the activity in the reserve for settling insured claims and expenses incurred in the claims settlement process for the period. The estimated liability includes the amount of money that will be required for future payments of (a) claims that have been reported to the insurer, (b) claims related to insured events that have occurred but that have not been reported to the insurer as of the date the liability is estimated, and (c) claim adjustment expenses. Claim adjustment expenses include costs incurred in the claim settlement process such as legal fees; outside adjuster fees; and costs to record, process, and adjust claims.+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437+ Details**Name:**
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