Revenue Recognition - Management Program (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Vogtle Units No. 3 & No. 4
Operating revenues
Amounts billed under rate management program	$ 8,966,000	$ 5,400,000
Cumulative recovery of financing costs	75,282,000
Vogtle New Units
Operating revenues
Amounts billed under additional rate management program	$ 23,380,000	$ 6,174,000