| **Condensed Financial Statements Of Parent Company Condensed Balance Sheets (Details) - USD ($) $ in Millions** | Dec. 31, 2023 | Dec. 31, 2022 |
|-----------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Condensed Financial Statements, Captions**                                                                    |          |          |
| Equity securities, cost                                                                                         | $ 4,282       | $ 4,294       |
| Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment                            | 337           | 322           |
| Cincinnati Financial Corporation                                                                                |          |          |
| **Condensed Financial Statements, Captions**                                                                    |          |          |
| Amortized cost of fixed maturities                                                                              | 184           | 91            |
| Equity securities, cost                                                                                         | 1,645         | 1,734         |
| Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment                            | $ 164         | $ 156         |

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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - 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.
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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.
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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).
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| - 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.
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| X                                                                                                                                            |
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