Vogtle Units No. 3 and No. 4 Construction Project - Narrative (Details) $ in Millions					3 Months Ended	9 Months Ended
	Oct. 06, 2023 USD ($)	Oct. 05, 2023 USD ($)	Oct. 04, 2023 USD ($)	Feb. 18, 2019 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2023 USD ($) unit MW	Jul. 31, 2023 USD ($)	Dec. 31, 2021 USD ($)
Loan Guarantee Agreement
Public Utility Property Plant and Equipment
Term of debt						5 years
Vogtle Units No. 3 & No. 4
Public Utility Property Plant and Equipment
Ownership interest (as a percent)					30.00%	30.00%
COVID related costs						$ 440.0
Proportionate share of COVID related costs						$ 130.0
Remaining share paid by counterparty upon exercise of tender option (as a percent)					100.00%	100.00%
Budget increases since the nineteenth VCM								$ 3,400.0
Percentage of disallowed costs excluded from adverse event triggers					6.00%	6.00%
Vogtle Units No. 3 & No. 4 | Jointly Owned Nuclear Power Plant
Public Utility Property Plant and Equipment
Total project cost						$ 8,300.0
Vogtle Units No. 3 & No. 4 | Financial Exposure Term One
Public Utility Property Plant and Equipment
Ownership interest (as a percent)					30.00%	30.00%
Vogtle Units No. 3 & No. 4 | Financial Exposure Term Two
Public Utility Property Plant and Equipment
Ownership interest (as a percent)					30.00%	30.00%
Vogtle Units No. 3 & No. 4 | EPC Agreement | Westinghouse Electric Company LLC and Stone & Webster, Inc.
Public Utility Property Plant and Equipment
Number of nuclear units | unit						2
Generating capacity of each nuclear unit (in megawatts) | MW						1,100
Vogtle Units No. 3 & No. 4 | Services Agreement | Westinghouse Electric Company LLC and Stone & Webster, Inc.
Public Utility Property Plant and Equipment
Written notice period for termination of agreement						30 days
Vogtle Units No. 3 & No. 4 | Ownership participation agreement
Public Utility Property Plant and Equipment
Ownership share, generating capacity (in megawatts) | MW						660
Project budget						$ 8,300.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet
Public Utility Property Plant and Equipment
Project budget				$ 8,400.0
Additional construction costs				$ 800.0
Total project cost						17,100.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Jointly Owned Nuclear Power Plant
Public Utility Property Plant and Equipment
Total project cost						17,100.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Jointly Owned Nuclear Power Plant | Georgia Power
Public Utility Property Plant and Equipment
Total project cost						$ 18,380.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Jointly Owned Nuclear Power Plant | Georgia Power | Subsequent Event
Public Utility Property Plant and Equipment
Project budget		$ 19,200.0
Cost-sharing bands, total liability		99.0
Cost-sharing bands, financing costs		5.0
Payments for cost-sharing bands		66.5	$ 37.5
Total construction costs to be paid	$ 105.1	346.3
Total construction costs paid		$ 241.2
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Financial Exposure Term One
Public Utility Property Plant and Equipment
Proportionate share of construction costs, co-owner (as a percent)				55.70%
Additional construction costs, responsibility of co-owner				$ 80.0
Proportionate share of additional construction costs				$ 44.0
Proportionate share of construction costs, remaining co-owners (as a percent)				44.30%
Proportionate share of construction costs (as a percent)				24.50%
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Financial Exposure Term Two
Public Utility Property Plant and Equipment
Proportionate share of construction costs, co-owner (as a percent)				65.70%
Additional construction costs, responsibility of co-owner				$ 100.0
Proportionate share of additional construction costs				$ 55.0
Proportionate share of construction costs, remaining co-owners (as a percent)				34.30%
Proportionate share of construction costs (as a percent)				19.00%
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Financial Exposure Term Three
Public Utility Property Plant and Equipment
Additional construction costs triggering option to tender ownership				$ 2,100.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Minimum
Public Utility Property Plant and Equipment
Ownership approval to change primary construction contractor (as a percent)					90.00%	90.00%
Ownership approval required to continue construction (as a percent)					90.00%	90.00%
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Minimum | Jointly Owned Nuclear Power Plant | Georgia Power | Subsequent Event
Public Utility Property Plant and Equipment
Percent of incremental costs that exceed project budget		3000.00%
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Minimum | Financial Exposure Term One
Public Utility Property Plant and Equipment
Additional construction costs				800.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Minimum | Financial Exposure Term Two
Public Utility Property Plant and Equipment
Additional construction costs				1,600.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Maximum | Jointly Owned Nuclear Power Plant | Georgia Power | Subsequent Event
Public Utility Property Plant and Equipment
Percent of incremental costs that exceed project budget		6600.00%
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Maximum | Financial Exposure Term One
Public Utility Property Plant and Equipment
Additional construction costs				1,600.0
Vogtle Units No. 3 & No. 4 | Global Amendments to Term Sheet | Maximum | Financial Exposure Term Two
Public Utility Property Plant and Equipment
Additional construction costs				$ 2,100.0
Vogtle Unit Number 3
Public Utility Property Plant and Equipment
Amount in service							$ 4,800.0
Vogtle Unit Number 3 | Georgia Power
Public Utility Property Plant and Equipment
Nuclear production tax credit					$ 8.6
Vogtle Unit Number 4 | Minimum
Public Utility Property Plant and Equipment
Monthly delay cost, exercise of tender option						$ 20.0