REGULATORY MATTERS - GPC Nuclear Construction (Details) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2012 utility MW
Public Utilities, General Disclosures [Line Items]
Estimated loss on Plant Vogtle Units 3 and 4					$ 1,692		$ 0
Georgia Power
Public Utilities, General Disclosures [Line Items]
Number of construction units approved | utility								2
Electric generating capacity (in MWs) | MW								1,100
Estimated loss on Plant Vogtle Units 3 and 4	$ 480	$ 264	$ 460	$ 48	$ 1,692	$ 325	$ 0
Estimated loss on Plant Vogtle Units 3 and 4, net of tax	358	$ 197	$ 343	$ 36
Pre-tax charge to income	440
After tax charge to income	$ 328
Plant Vogtle Units 3 and 4 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Percent ownership	45.70%				45.70%
Estimated construction financing costs	$ 3,400				$ 3,400
Construction financing costs incurred to date	2,900				2,900
Estimated cost to complete, construction contingency estimate and additional costs	1,300				1,300
Estimated cost to complete, additional construction contingency estimate	99				$ 99
Plant Vogtle Units 3 and 4 | Georgia Power | Minimum | COVID-19
Public Utilities, General Disclosures [Line Items]
Estimated months of productivity loss					3 months
Construction financing costs	160				$ 160
Plant Vogtle Units 3 and 4 | Georgia Power | Maximum | COVID-19
Public Utilities, General Disclosures [Line Items]
Estimated months of productivity loss					4 months
Construction financing costs	$ 200				$ 200
Plant Vogtle Units 3 and 4 | Georgia Power | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Period of notice required in the event letters of credit are not renewed					30 days
Plant Vogtle Unit 3 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Additional base capital costs per month (up to)					$ 60
Plant Watson Unit 4 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Additional base capital costs per month (up to)					$ 40