DERIVATIVES - Pre-Tax Effects of Derivatives Not Designated as Hedging (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2024 |
Dec. 31, 2023 |
Dec. 31, 2022 |
|
| Energy-related derivatives | Natural gas revenues | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Derivative instruments not designated as hedging instruments, gain (loss), net | $ 0 | $ 0 | $ (11) |
| Energy-related derivatives | Cost of natural gas | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Derivative instruments not designated as hedging instruments, gain (loss), net | 94 | 59 | (65) |
| Energy-related derivatives | Cost of natural gas | Not Designated as Hedging Instrument | Southern Company Gas | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Derivative instruments not designated as hedging instruments, gain (loss), net | 94 | 59 | (76) |
| Weather derivatives | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Derivative instruments not designated as hedging instruments, gain (loss), net | $ 12 | $ 15 | $ (7) |