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DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on Income (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Depreciation and amortization | $ 4,755 | $ 4,525 | $ 3,663
Interest expense, net of amounts capitalized | (2,743) | (2,446) | (2,022)
Other income (expense), net | 530 | 553 | 500
Natural gas |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Cost of sales | 1,196 | 1,644 | 3,004
Energy-related derivatives | Cost of Sales | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (40) | (44) | 37
Energy-related derivatives | Operating Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on hedges | (2) | (2) | 0
Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (6) | (23) | (5)
Interest rate derivatives | Interest Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (16) | (35) | (25)
Interest rate derivatives | Interest Expense | Fair Value Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (4) | 37 | (291)
Foreign currency derivatives | Interest Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (12) | (11) | (19)
Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (33) | 19 | (83)
Foreign currency fair value hedges | 2 | 69 | (106)
Amount excluded from effectiveness testing recognized in earnings | (16) | (21) | 24
Southern Power |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Depreciation and amortization | 522 | 504 | 516
Interest expense, net of amounts capitalized | (117) | (129) | (138)
Other income (expense), net | 13 | 12 | 7
Southern Power | Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (6) | (23) | (5)
Southern Power | Foreign currency derivatives | Interest Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (12) | (11) | (19)
Southern Power | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | (33) | 19 | (83)
Southern Company Gas |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Cost of sales | 1,196 | 1,644 | 3,004
Depreciation and amortization | 650 | 582 | 559
Interest expense, net of amounts capitalized | (341) | (310) | (263)
Other income (expense), net | 66 | 57 | 53
Southern Company Gas | Energy-related derivatives | Operating Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on hedges | (2) | (2) | 0
Southern Company Gas | Interest rate derivatives | Interest Expense | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on hedges | (1) | (19) | (4)
Southern Company Gas | Interest rate derivatives | Interest Expense | Fair Value Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on hedges | (5) | 6 | (86)
Southern Company Gas | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |
Gain (loss) on derivative | $ (40) | $ (44) | $ 37

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