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Acquisitions and Dispositions - Narrative (Details) - SOUTHERN POWER CO $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) MW
Millers Branch Solar Development Phase 2
Business Combination [Line Items]
Approximate nameplate capacity | MW	180
Millers Branch Solar Development Phase 3
Business Combination [Line Items]
Approximate nameplate capacity | MW	132
Millers Branch Solar Development
Business Combination [Line Items]
Construction costs incurred to date	$ 692
Construction work in progress	387
Wind Facilities
Business Combination [Line Items]
Construction work in progress	432
Franklin And Wansley Natural Gas Facilities
Business Combination [Line Items]
Construction work in progress	$ 0
Franklin And Wansley Natural Gas Facilities | Maximum
Business Combination [Line Items]
Additional capacity | MW	400

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