Regulatory Matters - Georgia Power (Details) - GEORGIA POWER CO $ in Millions					9 Months Ended
	Sep. 24, 2019	Jul. 29, 2019 MW	Jul. 16, 2019 MW	Jun. 28, 2019	Sep. 30, 2019 USD ($) MW	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Alternate Rate Plan period				3 years
Requested increases effective January 1, 2020					$ 560
Requested increases effective January 1, 2021					144
Requested increases effective January 1, 2022					233
Proposed retail ROE	10.90%
Proposed equity ratio	56.00%
Percentage of earnings above the top of allowed ROE range shared with customers				66.67%
Percentage of earnings above the top of allowed ROE range not shared with customers				33.33%
Cost recovery, new nuclear									$ 99
Cost recovery, estimate, nuclear fuel					50
Under recovered CCR compliance cost					$ 157
Rejected proposed capacity of units for certification | MW			25
Requested recovery of under recovered CCR compliance costs, period					3 years
Approved capacity of units for solar generation resources (mw) | MW					2,210
Approved capacity of units for investment portfolio (mw) | MW					80
Minimum
Public Utilities, General Disclosures [Line Items]
Allowed retail ROE				10.00%
Maximum
Public Utilities, General Disclosures [Line Items]
Allowed retail ROE				12.00%
Plant Hammond Units 1 Through 4
Public Utilities, General Disclosures [Line Items]
Capacity of units included in request for decertification of units (mw) | MW		840
Net book value of planned units retirements					$ 500
Plant McIntosh Unit 1
Public Utilities, General Disclosures [Line Items]
Capacity of units included in request for decertification of units (mw) | MW		142.5
Net book value of planned units retirements					40
Plant Hammond and Plant McIntosh Units
Public Utilities, General Disclosures [Line Items]
Net book value of planned units retirements					295
Plant Mitchell Unit 3
Public Utilities, General Disclosures [Line Items]
Net book value of planned units retirements					$ 8
Remaining Net Book Value Of Retired Assets | Maximum
Public Utilities, General Disclosures [Line Items]
Regulatory asset, amortization period					3 years
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Recovery of estimated under recovered CCR rule costs						$ 655	$ 395	$ 277