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ACQUISITIONS AND DISPOSITIONS - GAS Acquisitions and Dispositions Narrative (Details) - Disposal Group, Disposed of by Sale, Not Discontinued Operations - Natural Gas Storage Facilities - Southern Company Gas $ in Millions | 3 Months Ended |
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Dec. 31, 2022 USD ($) | Sep. 30, 2022 USD ($) storageFacility
Business Acquisition [Line Items] |  |
Number of natural gas storage facilities sold | storageFacility |  | 2
Consideration for sale |  | $ 186
Gain (loss) on dispositions | $ (131) |
Gain (loss) on dispositions, after tax | $ (99) |

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 805 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479907/805-20-50-5 + Details
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