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Fair Value Measurements - Narrative (Details) $ in Millions | Sep. 30, 2021 USD ($) professional
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Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
AFG's internal investment professionals | professional | 20
Level 3 | Continuing operations |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
Level 3 assets as a percentage of total assets measured at fair value | 5.00%
Percentage of level 3 assets that were priced using non-binding broker quotes | 17.00%
Level 3 assets that were priced using non-binding broker quotes | $ 150
Level 3 assets that were priced by pricing services. | $ 61
Percentage of level 3 assets that were priced by pricing services | 7.00%
Percentage of level 3 equity investments that do not qualify for equity accounting | 17.00%
Level 3 assets that are equity securities that do not qualify for equity accounting | $ 149
Internally developed level 3 assets | $ 519
Percentage of internally developed level 3 assets compared to total level 3 assets | 58.00%

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