REGULATORY MATTERS - GPC Joint Ownership Agreements (Details) - Georgia Power - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2015
Public Utilities, General Disclosures [Line Items]
Amortization period	5 years
Pre-tax charge to income		$ 440
After tax charge to income		$ 328
Plant Vogtle Units 3 and 4
Public Utilities, General Disclosures [Line Items]
Ownership interest percentage required for voting for continuing construction		90.00%	90.00%
Production tax credits, aggregate purchase price (up to)			$ 300
Preliminary estimated cost to complete		$ 10,401	10,401
Additional construction capital costs			$ 460	$ 3,300
Remaining share of construction costs, agreement to pay, percentage			100.00%
Percentage of costs, disallowed for recovery			6.00%
Costs disallowed for recovery, period			6 months
Public utilities, extension project schedule, term			1 year
Estimated cost to complete, starting dollar amount		$ 18,380	$ 18,380
Percent ownership		45.70%	45.70%
Plant Vogtle Units 3 and 4 | Minimum
Public Utilities, General Disclosures [Line Items]
Global amendments, tender provision, decision period after tender option triggered			120 days
Plant Vogtle Units 3 and 4 | Maximum
Public Utilities, General Disclosures [Line Items]
Global amendments, tender provision, decision period after tender option triggered			180 days
Plant Vogtle Units 3 and 4 | Category I
Public Utilities, General Disclosures [Line Items]
Preliminary estimated cost to complete		$ 8,400	$ 8,400
Additional construction capital costs, threshold			$ 800
Plant Vogtle Units 3 and 4 | Category II
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay			55.70%
Additional construction capital costs			$ 80
Plant Vogtle Units 3 and 4 | Category II | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay			44.30%
Plant Vogtle Units 3 and 4 | Category II | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold			$ 800
Plant Vogtle Units 3 and 4 | Category II | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold			$ 1,600
Plant Vogtle Units 3 and 4 | Category III
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay			65.70%
Additional construction capital costs			$ 100
Plant Vogtle Units 3 and 4 | Category III | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay			34.30%
Plant Vogtle Units 3 and 4 | Category III | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold			$ 2,100