|**Valuation And Qualifying Accounts**             | 12 Months Ended                                                                                                                                                                                                                                                                                                
|------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Valuation and Qualifying Accounts [Abstract]**  |                                                                                                                                                                                                                                                                                                                
|Valuation And Qualifying Accounts                 | Schedule VCincinnati Financial Corporation and SubsidiariesValuation and Qualifying Accounts(Dollars in millions)At December 31,201620152014Allowance for doubtful receivables:Beginning balance, January 1$4$3$2Additions charged to costs and expenses532Deductions(4)(2)(1)Ending balance, December 31$5$4$3
|                                                 
|                                                  |                                                                                                                                                                                                                                                                                                                
|Cincinnati Financial Corporation and Subsidiaries
|Valuation and Qualifying Accounts                
|(Dollars in millions)                             |                                                                                                                                                                                                                                                                                                                
|                                                  |                                                                                                                                                                                                                                                                                                                
|Allowance for doubtful receivables:               |                                                                                                                                                                                                                                                                                                                
|Beginning balance, January 1                      |                                                                                                                                                                                                                                                                                                                
|Additions charged to costs and expenses           |                                                                                                                                                                                                                                                                                                                
|Deductions                                        |                                                                                                                                                                                                                                                                                                                
|Ending balance, December 31                       |                                                                                                                                                                                                                                                                                                                
|                                                  |                                                                                                                                                                                                                                                                                                                

X- DefinitionThe entire disclosure for any allowance and reserve accounts (their beginning and ending balances, as well as a reconciliation by type of activity during the period). Alternatively, disclosure of the required information may be within the footnotes to the financial statements or a supplemental schedule to the financial statements.
+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690
+ Details**Name:**
us-gaap_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock**Namespace Prefix:**
us-gaap_**Data Type:**
nonnum:textBlockItemType**Balance Type:**
na**Period Type:**
duration X- ReferencesNo definition available.
+ Details**Name:**
us-gaap_ValuationAndQualifyingAccountsAbstract**Namespace Prefix:**
us-gaap_**Data Type:**
xbrli:stringItemType**Balance Type:**
na**Period Type:**
duration