Contingencies - SPC Litigation (Details) - Southern Power $ in Millions |
12 Months Ended |
|---|---|
|
Dec. 31, 2018
USD ($)
| |
| Loss Contingencies [Line Items] | |
| Construction contract payment withheld | $ 26 |
| RE Roserock, LLC | |
| Loss Contingencies [Line Items] | |
| Noncontrolling ownership percentage held by parent | 51.00% |