REGULATORY MATTERS - GPC Regulatory Matters (Details) $ in Millions					1 Months Ended	12 Months Ended				84 Months Ended
	Dec. 17, 2019	Dec. 16, 2019	Jan. 31, 2019 MW	Apr. 03, 2018	Feb. 29, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) MW	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2013
Schedule of Regulatory Assets and Liabilities [Line Items]
Contract with customer, liability, bill credits							$ 50
Effective income tax rate							27.50%	16.30%	13.30%
Deferred income taxes							$ 611	$ 89	$ 166
Total regulatory assets (liabilities), net							3,838	720
Other regulatory assets							885	525
Other regulatory assets, deferred							6,805	5,375
Remaining net book value of retired assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net							$ 1,275	$ 211
Maximum | Remaining net book value of retired assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory amortization period							18 years
Scenario, Forecast | Customers
Schedule of Regulatory Assets and Liabilities [Line Items]
Percentage basis net merger savings										60.00%
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Retail rate of return on common equity							10.50%						10.95%
Portion of actual earnings above approved ROE band applied to reduce regulatory assets (percent)	40.00%
Portion of actual earnings above approved ROE band retained by subsidiary company (percent)	20.00%
Portion of actual earnings above approved ROE band refunded to customers (percent)	40.00%	66.67%					50.00%
Portion of actual earnings above approved ROE band refunded to customers, used to reduce regulatory assets (percent)							50.00%	50.00%
Portion of actual earning above approved ROE band refunded to customers, used to reduce regulatory assets, value							$ 60	$ 50
Portion of actual earnings above approved ROE band refunded to customers, value							60
Customer refund liability, noncurrent							330
Customer refund							55
Customer refund liability in absence of base rate case							110		$ 4
Contract with customer, liability, bill credits							$ 95	$ 130
Effective income tax rate							21.50%	21.30%	36.70%
Deferred income taxes							$ 179	$ (260)	$ 458
Under recovered CCR rule							$ 175
Proposed capacity of units for certification (in mw) | MW							25
Approved capacity of units for solar generation resources (mw) | MW							2,210
Proposed capacity of units for investment portfolio (mw) | MW							80
Approved increase (decrease) in annual billing based on fuel cost recovery rate												$ 313
Adjustment to fuel cost recovery rate if under recovered fuel balance exceeds budget thereafter							$ 200
Over recovered fuel balance							$ 73	115
Required period for options and hedges							48 months
Total regulatory assets (liabilities), net							$ 3,507	2,378
Other regulatory assets							263	169
Other regulatory assets, deferred							2,716	2,258
Georgia Power | Remaining net book value of retired assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net							596	127
Georgia Power | Storm damage reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net							410	416
Georgia Power | Property damage reserves-liability
Schedule of Regulatory Assets and Liabilities [Line Items]
Other regulatory assets							213	30
Other regulatory assets, deferred							$ 197	$ 386
Georgia Power | Minimum
Schedule of Regulatory Assets and Liabilities [Line Items]
Retail rate of return on common equity							9.50%						10.00%
Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Retail rate of return on common equity							12.00%						12.00%
Retail regulatory equity ratio	0.56	0.55
Cost recovery, estimate, nuclear fuel							$ 50
Georgia Power | Maximum | Remaining net book value of retired assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory amortization period							3 years
Georgia Power | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Percentage basis net merger savings										40.00%
Portion of actual earnings above approved ROE band refunded to customers (percent)						50.00%
Portion of actual earnings above approved ROE band refunded to customers, value						$ 50
Contract with customer, liability, bill credits					$ 105
Recovery estimate of under recovered CCR rule costs						$ 265				$ 390	$ 290
Georgia Power | Deferred income tax charges
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities							$ 659
Regulatory liability amortization period							3 years
Georgia Power | State and Local Jurisdiction
Schedule of Regulatory Assets and Liabilities [Line Items]
Effective income tax rate				6.00%			5.75%
Plant Hammond Units 1 through 4 | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Capacity of units included in request for decertification of units (mw) | MW			840
Net book value of planned units retirements							$ 488
Plant McIntosh Unit 1 | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Capacity of units included in request for decertification of units (mw) | MW			142.5
Net book value of planned units retirements							30
Plant Hammond and Plant McIntosh Units | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Net book value of planned units retirements							295
Unusable materials and supplies inventory							$ 20