REGULATORY MATTERS - Schedule of Nuclear Construction Cost and Schedule (Details) - USD ($) $ in Millions		12 Months Ended
	Feb. 18, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Commitments [Line Items]
Total AFUDC and interest capitalized		$ 202	$ 210	$ 249
Georgia Power
Commitments [Line Items]
Total AFUDC and interest capitalized		103	$ 94	$ 63
Customer refund		55
Georgia Power | Plant Vogtle Units 3 And 4
Commitments [Line Items]
Base project capital cost forecast		8,200
Construction contingency estimate		200
Total project capital cost forecast		8,400
Net investment		(5,900)
Remaining estimate to complete		2,500
Total AFUDC and interest capitalized		300
Total AFUDC and interest capitalized, accrual amount		$ 23
Subsequent Event | Twenty First Vogtle Construction Monitoring Report | Georgia Power | Plant Vogtle Units 3 And 4
Commitments [Line Items]
Maximum guarantee	$ 1,700
Customer refund	$ 188