v3.25.0.1
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