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Fair Value Measurements (Details Textual) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2016 USD ($) professional stock | Mar. 31, 2015 USD ($) stock | Dec. 31, 2015 USD ($)
Fair Value Measurements (Textual) [Abstract] |  |  |
AFG's internal investment professionals | professional | 25 |  |
Number of stocks transferred from Level 1 to Level 2 | stock |  | 0 |
Level 3 assets as a percentage of total assets measured at fair value | 4.00% |  |
Percentage of level 3 assets that were priced using non-binding broker quotes | 73.00% |  |
Level 3 assets that were priced using non-binding broker quotes | $ 1,290 |  |
Life contingent annuities | $ 199 |  | $ 200
Maximum [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Percentage of internally developed Level 3 asset fair values to Shareholders' equity (are less than) | 10.00% |  |
Fixed-indexed annuties (embedded derivative), majority of future years [Member] | Minimum [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Unobservable input surrenders used in Level 3 fair value determination | 5.00% |  |
Fixed-indexed annuties (embedded derivative), majority of future years [Member] | Maximum [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Unobservable input surrenders used in Level 3 fair value determination | 10.00% |  |
Fixed-indexed annuities (embedded derivative) [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Fair value of derivatives in annuity benefits accumulated measured using a discounted cash flow approach | $ 1,450 |  |
Fixed-indexed annuities (embedded derivative) [Member] | Minimum [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Unobservable input surrenders used in Level 3 fair value determination | 3.00% |  |
Fixed-indexed annuities (embedded derivative) [Member] | Maximum [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Unobservable input surrenders used in Level 3 fair value determination | 18.00% |  |
Common stocks [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Number of stocks transferred from Level 2 to Level 1 | stock |  | 1 |
Fair value of assets transferred from Level 2 to Level 1, during the first three months |  | $ 53 |
Perpetual preferred stocks [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Number of stocks transferred from Level 2 to Level 1 | stock | 1 | 2 |
Fair value of assets transferred from Level 2 to Level 1, during the first three months | $ 8 | $ 5 |
Number of stocks transferred from Level 1 to Level 2 | stock | 3 |  |
Fair value of assets transferred from Level 1 to Level 2, during the first three months | $ 6 |  |
Run-off long-term care insurance business [Member] |  |  |
Fair Value Measurements (Textual) [Abstract] |  |  |
Estimated sale proceeds of the run-off long-term care insurance business |  | $ 14 |

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