Revenue from Contracts with Customers and Lease Income - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 2,423	$ 3,123
Contract Assets	167	156
Contract Liabilities	73	45
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	670	696
Contract Assets	0	2
Contract Liabilities	1	4
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	986	922
Contract Assets	73	89
Contract Liabilities	28	9
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	101	92
Contract Assets	0	0
Contract Liabilities	3	0
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	126	237
Contract Assets	0	0
Contract Liabilities	1	1
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Accounts Receivable	461	1,107
Contract Assets	30	0
Contract Liabilities	$ 0	$ 0