| **Supplementary Insurance Information**            | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   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| **Supplementary Insurance Information [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   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| Supplementary Insurance Information                | Schedule IIICincinnati Financial Corporation and SubsidiariesSupplementary Insurance Information(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 property casualty insurance 366 337 303Life insurance 199 133 174Total $565 $470 $477       Gross future policy benefits, losses, claims and expense losses:      Commercial lines insurance $3,667 $3,645 $3,780Personal lines insurance 417 398 419Excess and surplus lines insurance 157 126 81Total property casualty insurance 4,241 4,169 4,280Life insurance 2,441 2,341 2,257Total (1) $6,682 $6,510 $6,537       Gross unearned premiums:      Commercial lines insurance $1,372 $1,246 $1,149Personal lines insurance 535 490 440Excess and surplus lines insurance 67 54 42Total property casualty insurance 1,974 1,790 1,631Life insurance 2 2 2Total (1) $1,976 $1,792 $1,633       Other policy claims and benefits payable:      Commercial lines insurance $— $— $—Personal lines insurance — — —Excess and surplus lines insurance — — —Total property casualty insurance — — —Life insurance 19 15 16Total (1) $19 $15 $16       Earned premiums:      Commercial lines insurance $2,636 $2,383 $2,197Personal lines insurance 961 868 762Excess and surplus lines insurance 116 93 70Total property casualty insurance 3,713 3,344 3,029Life insurance 189 178 165Total $3,902 $3,522 $3,194        Schedule III (continued)Cincinnati Financial Corporation and SubsidiariesSupplementary Insurance Information(In millions) Years ended December 31,  2013 2012 2011Investment income, net of expenses:      Commercial lines insurance $— $— $—Personal lines insurance — — —Excess and surplus lines insurance — — —Total property casualty insurance (2) 348 351 350Life insurance 140 137 134Total $488 $488 $484       Benefits, claims losses and settlement expenses:      Commercial lines insurance $1,596 $1,420 $1,570Personal lines insurance 639 652 723Excess and surplus lines insurance 66 65 42Total property casualty insurance 2,301 2,137 2,335Life insurance 204 185 189Total $2,505 $2,322 $2,524       Amortization of deferred policy acquisition costs:      Commercial lines insurance $514 $462 $441Personal lines insurance 192 183 144Excess and surplus lines insurance 21 17 13Total property casualty insurance 727 662 598Life insurance 31 45 33Total (3) $758 $707 $631       Underwriting, acquisition and insurance expenses:      Commercial lines insurance $343 $324 $291Personal lines insurance 98 78 78Excess and surplus lines insurance 15 12 9Total property casualty insurance 456 414 378Life insurance 29 34 30Total (3) $485 $448 $408       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 property casualty insurance 3,893 3,482 3,098Accident health insurance 2 3 3Total $3,895 $3,485 $3,101       Notes to Schedule III:(1) The sum of gross future policy benefits, losses, claims and expense losses, gross unearned premium and other policy claims and benefits payable is equal to the sum of Loss and loss expense reserves, Life policy reserves and investment contract reserves and Unearned premiums reported in the company’s consolidated balance sheets. (2) This segment information is not regularly allocated to segments and reviewed by company management in making decisions about resources to be allocated to the segments or to assess their performance.(3) The sum of amortization of deferred policy acquisition costs and other underwriting and insurance expenses is equal to Underwriting, acquisition and insurance expenses in the consolidated statements of income.  |

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| - Definition
The entire disclosure for required supplementary insurance information giving segment detail in support of various balance sheet and income statement captions. The balance sheet information generally is presented as of the date of each audited balance sheet filed, and the income statement information generally is presented for each period for which an audited income statement is required to be filed. Supplementary insurance information table includes segment name; deferred policy acquisition costs; future policy benefits, losses, claims and loss expenses; unearned premiums; other policy claims and benefits payable; premium revenue; net investment income; benefits, claims, losses and settlement expenses; amortization of deferred policy acquisition costs; other operating expenses; and premiums written.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 16 -Article 12Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 05 -Paragraph c -Article 7Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-16) -URI http://asc.fasb.org/extlink&oid=6588446&loc=d3e574960-122915Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 10 -Section S99 -Paragraph 3 -Subparagraph (SX 210.7-05.(c) Schedule III) -URI http://asc.fasb.org/extlink&oid=6879921&loc=d3e569147-122900
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