Regulatory Matters - APC Certificate of Convenience and Necessity (Details) - USD ($) $ in Millions	Oct. 03, 2022	Sep. 30, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation		$ 81,314	$ 81,513
Other utility plant, net		602	0
Construction work in progress		10,773	8,771
Revision of Prior Period, Reclassification, Adjustment
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation		(600)
Other utility plant, net		600
ALABAMA POWER CO
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation		22,649	22,822
Other utility plant, net		602	0
Construction work in progress		1,524	$ 1,147
ALABAMA POWER CO | Plant Barry Unit 8
Public Utilities, General Disclosures [Line Items]
Estimated in-service cost				$ 652
Construction work in progress		$ 484
Subsequent Event | ALABAMA POWER CO
Public Utilities, General Disclosures [Line Items]
Increase to annual revenue requirement	$ 34
Increase to annual revenue requirement, percentage	0.60%