Consolidated Entities and Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions |
Jun. 30, 2026 |
Dec. 31, 2025 |
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| Schedule of Equity Method Investments [Line Items] | ||
| Investment Balance | $ 1,428 | $ 1,318 |
| SOUTHERN Co GAS | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Investment Balance | 1,254 | 1,182 |
| SOUTHERN Co GAS | SNG | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Investment Balance | 1,220 | 1,148 |
| SOUTHERN Co GAS | Other | ||
| Schedule of Equity Method Investments [Line Items] | ||
| Investment Balance | $ 34 | $ 34 |
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- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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