Regulatory Matters - Nuclear Construction Cost and Schedule (Details) - GEORGIA POWER CO - Plant Vogtle Units 3 And 4 $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($)
Loss Contingencies [Line Items]
Base project capital cost forecast	$ 8,000
Construction contingency estimate	400
Total project capital cost forecast	8,400
Net investment as of March 31, 2019	(4,900)
Remaining estimate to complete	3,500
Expected capitalized costs	325
Guarantor obligations	1,700
Customer refund	$ 188