INTRODUCTION - Other Intangible Assets, Amortization (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended |
|---|---|---|
Jun. 30, 2020 |
Jun. 30, 2020 |
|
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of intangible assets | $ 13 | $ 25 |
| Decrease in operating revenues | 5 | 11 |
| SOUTHERN POWER CO | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of intangible assets | 5 | 10 |
| SOUTHERN Co GAS | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of intangible assets | 5 | 10 |
| Gas Marketing Services | SOUTHERN Co GAS | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of intangible assets | 5 | 9 |
| Wholesale Gas Services | SOUTHERN Co GAS | ||
| Finite-Lived Intangible Assets [Line Items] | ||
| Amortization of intangible assets | $ 0 | $ 1 |