Acquisitions and Dispositions - Schedule of Asset Acquisition (Details) - SOUTHERN POWER CO - Deuel Harvest $ in Millions		6 Months Ended
	Mar. 30, 2021 USD ($)	Jun. 30, 2021 MW
Business Acquisition [Line Items]
Approximate nameplate capacity (in MWs) | MW		300
Proceeds from tax equity transaction | $	$ 220
Maximum
Business Acquisition [Line Items]
PPA Contract Period		25 years
Minimum
Business Acquisition [Line Items]
PPA Contract Period		15 years
Deuel Harvest
Business Acquisition [Line Items]
Ownership percentage by parent		100.00%