Derivatives - Schedule of Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Derivative [Line Items]
Notional Amount	$ 3,400
Fair Value Gain (Loss)	(258)
GEORGIA POWER CO | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Notional Amount	$ 750
Weighted Average Interest Rate Paid	3.63%
Fair Value Gain (Loss)	$ (1)
Southern Company parent | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Notional Amount	$ 500
Weighted Average Interest Rate Paid	3.47%
Fair Value Gain (Loss)	$ 0
Southern Company parent | Fair Value Hedges of Existing Debt | March 2028
Derivative [Line Items]
Notional Amount	$ 400
Interest Rate Received	1.75%
Fair Value Gain (Loss)	$ (45)
Southern Company parent | Fair Value Hedges of Existing Debt | April 2030
Derivative [Line Items]
Notional Amount	$ 1,000
Interest Rate Received	3.70%
Fair Value Gain (Loss)	$ (142)
SOUTHERN Co GAS | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Notional Amount	$ 250
Weighted Average Interest Rate Paid	3.40%
Fair Value Gain (Loss)	$ 1
SOUTHERN Co GAS | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 500
Interest Rate Received	1.75%
Fair Value Gain (Loss)	$ (71)
London Interbank Offered Rate (LIBOR) | Southern Company parent | Fair Value Hedges of Existing Debt | March 2028
Derivative [Line Items]
Weighted Average Interest Rate Paid	0.68%
London Interbank Offered Rate (LIBOR) | Southern Company parent | Fair Value Hedges of Existing Debt | April 2030
Derivative [Line Items]
Weighted Average Interest Rate Paid	2.36%
London Interbank Offered Rate (LIBOR) | SOUTHERN Co GAS | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Weighted Average Interest Rate Paid	0.38%