REGULATORY MATTERS - Nuclear Construction Cost and Schedule (Details) - GEORGIA POWER CO - Plant Vogtle Units 3 And 4 $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($)
Loss Contingencies [Line Items]
Base project capital cost forecast	$ 8,400
Construction contingency estimate	100
Total project capital cost forecast	8,500
Net investment as of September 30, 2019	(6,900)
Remaining estimate to complete	1,600
Expected capitalized costs	240
Capitalized interest accrued	$ 71