| **Supplementary Information Concerning Property Casualty Insurance Operations**       | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|---------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Supplemental Information for Property, Casualty Insurance Underwriters [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| Supplementary Information Concerning Property Casualty Insurance Operations           | Schedule VICincinnati Financial Corporation and SubsidiariesSupplementary Information Concerning Property Casualty Insurance Operations(In millions) Years ended December 31,  2013 2012 2011Deferred policy acquisition costs:      Commercial lines insurance $251 $235 $204Personal lines insurance 104 93 92Excess and surplus lines insurance 11 9 7Total $366 $337 $303       Reserves for unpaid claims and claim adjustment expenses:      Commercial lines insurance $3,667 $3,645 $3,780Personal lines insurance 417 398 419Excess and surplus lines insurance 157 126 81Total $4,241 $4,169 $4,280       Reserve discount deducted $— $— $—       Unearned premiums:      Commercial lines insurance $1,370 $1,246 $1,149Personal lines insurance 534 490 440Excess and surplus lines insurance 66 54 42Total $1,970 $1,790 $1,631       Earned premiums:      Commercial lines insurance $2,636 $2,383 $2,197Personal lines insurance 961 868 762Excess and surplus lines insurance 116 93 70Total $3,713 $3,344 $3,029       Investment income:      Commercial lines insurance $— $— $—Personal lines insurance — — —Excess and surplus lines insurance — — —Total (1) $348 $351 $350       Loss and loss expenses incurred related to current accident year:      Commercial lines insurance $1,691 $1,712 $1,804Personal lines insurance 678 751 765Excess and surplus lines insurance 79 70 51Total $2,448 $2,533 $2,620       Loss and loss expenses incurred related to prior accident years:      Commercial lines insurance $(95) $(292) $(234)Personal lines insurance (39) (99) (42)Excess and surplus lines insurance (13) (5) (9)Total $(147) $(396) $(285)       Amortization of deferred policy acquisition costs:      Commercial lines insurance $514 $461 $441Personal lines insurance 192 183 144Excess and surplus lines insurance 21 17 13Total $727 $661 $598       Paid loss and loss expenses:      Commercial lines insurance $1,498 $1,546 $1,545Personal lines insurance 639 659 676Excess and surplus lines insurance 35 24 20Total $2,172 $2,229 $2,241       Net written premiums:      Commercial lines insurance $2,760 $2,459 $2,218Personal lines insurance 1,005 918 801Excess and surplus lines insurance 128 105 79Total $3,893 $3,482 $3,098       Note to Schedule VI:(1) This segment information is not regularly allocated to segments and not reviewed by company management in making decisions about resources to be allocated to the segments or to assess their performance. |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The entire disclosure for the supplemental schedule of information for an entity who has a consolidated property-casualty insurance underwriter, unconsolidated property-casualty subsidiary or fifty percent-or-less owned property-casualty equity investee.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-18) -URI http://asc.fasb.org/extlink&oid=6588446&loc=d3e575016-122915Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 18 -Article 12
+ Details**Name:**us-gaap_ScheduleOfSupplementalInformationForPropertyCasualtyInsuranceUnderwritersTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SupplementalInformationForPropertyCasualtyInsuranceUnderwritersAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |