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STOCK COMPENSATION (Tables) | 12 Months Ended
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Dec. 31, 2023
Share-Based Payment Arrangement [Abstract] |
Schedule of employees participating in stock-based compensation programs | At December 31, 2023, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows:
| Southern Company | Alabama Power | Georgia Power | Mississippi Power | Southern Power | Southern Company Gas
Number of employees | 1,401 |  | 191 |  | 210 |  | 42 |  | 40 |  | 193 |
Assumptions used in the pricing model and the weighted average grant-date fair value of performance share award units granted | The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted:
Year Ended December 31 | 2023 |  | 2022 |  | 2021
Expected volatility | 30.0% |  | 29.6% |  | 30.0%
Expected term (in years) | 3 |  | 3 |  | 3
Interest rate | 3.8% |  | 1.7% |  | 0.2%
Weighted average grant-date fair value | $76.83 |  | $79.69 |  | $69.06
Schedule of compensation costs and related tax benefits | Total PSU compensation cost, and the related tax benefit recognized in income, for the years ended December 31, 2023, 2022, and 2021 are as follows:
| 2023 |  | 2022 |  | 2021
| (in millions)
Southern Company |  |  |  |  |
Compensation cost recognized in income | $ | 107 |  |  | $ | 101 |  |  | $ | 112 |
Tax benefit of compensation cost recognized in income | 28 |  |  | 26 |  |  | 29 |
Southern Company Gas |  |  |  |  |
Compensation cost recognized in income | $ | 14 |  |  | $ | 12 |  |  | $ | 17 |
Tax benefit of compensation cost recognized in income | 4 |  |  | 4 |  |  | 4 |
Total intrinsic value of options exercised, and the related tax benefit, for the years ended December 31, 2023, 2022, and 2021 are presented below for Southern Company and were immaterial for all other Registrants:
Year Ended December 31 | 2023 |  | 2022 |  | 2021
| (in millions)
Southern Company |  |  |  |  |
Intrinsic value of options exercised | $ | 18 |  |  | $ | 49 |  |  | $ | 34 |
Tax benefit of options exercised | 4 |  |  | 12 |  |  | 7 |
Share-based compensation, stock options, activity | Southern Company's activity in the stock option program for 2023 is summarized below:
| Shares Subject to Option |  | Weighted Average Exercise Price
| (in millions) |  |
Outstanding at December 31, 2022 | 1.0 |  |  | $ | 42.22 |
Exercised | 0.7 |  |  | 42.54 |
Outstanding and Exercisable at December 31, 2023 | 0.3 |  |  | $ | 41.58 |

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