REGULATORY MATTERS - GAS Schedule of Unrecognized Ratemaking Amounts (Details) - USD ($) $ in Millions |
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
|---|---|---|---|
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | $ 66 | $ 216 | |
| Regulatory Asset Off Balance Sheet | Atlanta Gas Light | |||
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | $ 11 | 23 | |
| Regulatory Asset Off Balance Sheet | Virginia Natural Gas | |||
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | 10 | 10 | |
| Regulatory Asset Off Balance Sheet | Chattanooga Gas | |||
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | 7 | 7 | |
| Regulatory Asset Off Balance Sheet | Nicor Gas | |||
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | 0 | 3 | |
| Regulatory Asset Off Balance Sheet | Southern Company Gas | |||
| Schedule of Regulatory Assets and Liabilities [Line Items] | |||
| Regulatory asset | $ 28 | $ 43 |