Contingencies - Environmental Remediation (Details) - USD ($) $ in Millions |
Jun. 30, 2019 |
Dec. 31, 2018 |
|---|---|---|
| GEORGIA POWER CO | ||
| Loss Contingencies [Line Items] | ||
| Environmental remediation liability, current and former sites | $ 18 | $ 23 |
| SOUTHERN Co GAS | ||
| Loss Contingencies [Line Items] | ||
| Environmental remediation liability, current and former sites | 283 | $ 294 |
| SOUTHERN Co GAS | Location One | ||
| Loss Contingencies [Line Items] | ||
| Environmental remediation liability, current and former sites | $ 2 |