FINANCING - DOE Loan Guarantee Borrowings (Details) - USD ($)	1 Months Ended			12 Months Ended
	Dec. 31, 2020	Jun. 30, 2020	Mar. 31, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Remaining borrowing capacity				$ 7,594,000,000
Line of credit facility, maximum borrowing capacity				7,655,000,000
Georgia Power
Debt Instrument [Line Items]
Percent of eligible project costs (may not exceed)			70.00%
Remaining borrowing capacity				1,726,000,000
Principal amortization payments				96,000,000	$ 73,000,000	$ 0
Line of credit facility, maximum borrowing capacity				$ 1,750,000,000
Basis spread on variable rate			0.375%
Amortization period			5 years
FFB Credit Facility | Georgia Power
Debt Instrument [Line Items]
Eligible project costs to be reimbursed			$ 5,130,000,000
Funds received under guarantee settlement agreement, less customer refunds			$ 1,492,000,000
Proceeds from lines of credit	$ 69,000,000	$ 371,000,000
Fixed stated interest rate of debt obligation		2.434%		2.178%
Remaining borrowing capacity				$ 0
Principal amortization payments				96,000,000
Line of credit facility, maximum borrowing capacity	$ 4,600,000,000			$ 5,000,000,000	$ 4,600,000,000
Plant Vogtle Units 3 and 4 | Georgia Power
Debt Instrument [Line Items]
Percent ownership				45.70%
Ownership interest percentage required for voting for continuing construction				90.00%