Regulatory Matters - GPC Amendments to the Vogtle Joint Ownership Agreements (Details) - Georgia Power - USD ($) $ in Thousands		3 Months Ended
	Jan. 11, 2018	Mar. 31, 2022	Aug. 31, 2018
Public Utilities, General Disclosures [Line Items]
Pre-tax charge to income		$ 440,000
After tax charge to income		328,000
Plant Vogtle Units 3 And 4
Public Utilities, General Disclosures [Line Items]
Production tax credits, aggregate purchase price, maximum		300,000
Preliminary estimated cost to complete		10,401,000
Additional construction capital costs	$ 3,300,000	$ 460,000
Remaining share of construction costs, agreement to pay, percentage		100.00%
Percentage of ownership interest required for voting for continuing construction			90.00%
Percentage of costs, disallowed for recovery		6.00%
Costs disallowed for recovery, period		6 months
Public utilities, extension project schedule, term		1 year
Estimated cost to complete, starting dollar amount		$ 18,380,000
Proportionate ownership share		45.70%
Plant Vogtle Units 3 And 4 | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs		$ 100
Plant Vogtle Units 3 And 4 | Category I
Public Utilities, General Disclosures [Line Items]
Preliminary estimated cost to complete		8,400,000
Additional construction capital costs, threshold		$ 800,000
Plant Vogtle Units 3 And 4 | Category II
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		55.70%
Additional construction capital costs		$ 80,000
Plant Vogtle Units 3 And 4 | Category II | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		44.30%
Plant Vogtle Units 3 And 4 | Category II | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 800,000
Plant Vogtle Units 3 And 4 | Category II | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 1,600,000
Plant Vogtle Units 3 And 4 | Category III
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		65.70%
Additional construction capital costs		$ 100,000
Plant Vogtle Units 3 And 4 | Category III | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		34.30%
Plant Vogtle Units 3 And 4 | Category III | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 1,600,000
Plant Vogtle Units 3 And 4 | Category III | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 2,100,000