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REGULATORY MATTERS - GAS Schedule of Unrecognized Ratemaking Amounts (Details) - USD ($) $ in Millions | 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 | 23 | 35
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 | 2
Regulatory Asset Off Balance Sheet | Nicor Gas |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |
Regulatory asset | 3 | 3
Regulatory Asset Off Balance Sheet | Southern Company Gas |  |
Schedule of Regulatory Assets and Liabilities [Line Items] |  |
Regulatory asset | $ 43 | $ 50

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- Definition The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 980 -SubTopic 340 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481878/980-340-50-1 + Details
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