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Fair Value Measurements - Schedule of Increase (Decrease) In Fair Value Of Funds (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2024 | Jun. 30, 2023 | Jun. 30, 2024 | Jun. 30, 2023
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |  |
Increase (decrease) in fair value of funds | $ 32 | $ 132 | $ 135 | $ 228
ALABAMA POWER CO |  |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |  |
Increase (decrease) in fair value of funds | 19 | 58 | 87 | 103
GEORGIA POWER CO |  |  |  |
Fair Value, Option, Quantitative Disclosures [Line Items] |  |  |  |
Increase (decrease) in fair value of funds | $ 13 | $ 74 | $ 48 | $ 125

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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 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 30 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-30 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 31 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-31 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 32 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-32 + Details
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