Acquisitions and Dispositions - Pre-tax Profit (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 30, 2019 |
Jun. 30, 2018 |
Jun. 30, 2019 |
Jun. 30, 2018 |
|
| GULF POWER CO | ||||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||||
| Earnings before income taxes | $ 0 | $ 31 | $ 0 | $ 87 |
| SOUTHERN POWER CO | Florida Plants | ||||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||||
| Earnings before income taxes | 0 | 14 | 0 | 24 |
| SOUTHERN POWER CO | Plant Nacogdoches | ||||
| Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] | ||||
| Earnings before income taxes | $ 9 | $ 7 | $ 16 | $ 13 |