Introduction - Asset Retirement Obligations (Details) $ in Millions |
6 Months Ended |
|---|---|
|
Jun. 30, 2019
USD ($)
| |
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |
| Balance at December 31, 2018 | $ 9,394 |
| Liabilities incurred | 6 |
| Liabilities settled | (142) |
| Accretion | 197 |
| Cash flow revisions | 452 |
| Balance at June 30, 2019 | 9,907 |
| ALABAMA POWER CO | |
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |
| Balance at December 31, 2018 | 3,210 |
| Liabilities incurred | 0 |
| Liabilities settled | (43) |
| Accretion | 70 |
| Cash flow revisions | 308 |
| Balance at June 30, 2019 | 3,545 |
| MISSISSIPPI POWER CO | |
| Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] | |
| Balance at December 31, 2018 | 160 |
| Liabilities incurred | 0 |
| Liabilities settled | (17) |
| Accretion | 2 |
| Cash flow revisions | 59 |
| Balance at June 30, 2019 | $ 204 |