Acquisitions and Dispositions - Schedule of Construction Projects (Details) - SOUTHERN POWER CO - MW	1 Months Ended		3 Months Ended	4 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2022	Feb. 28, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Garland Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	88		88		88
PPA Contract Period				20 years
Nameplate capacity placed in service (in MWs)		15	15			73
Tranquillity Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	72		72		72
PPA Contract Period					20 years
Nameplate capacity placed in service (in MWs)	40		40			32