| **Condensed Financial Statements Of Parent Company Condensed Balance Sheets (Details) - USD ($) $ in Millions** | Dec. 31, 2021 | Dec. 31, 2020 |
|-----------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Condensed Financial Statements, Captions**                                                                    |          |          |
| Amortized cost of fixed maturities                                                                              | $ 12,230      | $ 11,312      |
| Equity securities, cost                                                                                         | 4,121         | 3,927         |
| Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment                            | 303           | 285           |
| Cincinnati Financial Corporation                                                                                |          |          |
| **Condensed Financial Statements, Captions**                                                                    |          |          |
| Amortized cost of fixed maturities                                                                              | 64            | 69            |
| Equity securities, cost                                                                                         | 1,660         | 1,607         |
| Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment                            | $ 147         | $ 138         |

| X                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.
+ References
No definition available.
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| X                                                                                                                                            |
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