Revenue from Contracts with Customers and Lease Income - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 3,021	$ 2,504
Contract Assets	102	117
Contract Liabilities	70	57
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	773	589
Contract Assets	0	2
Contract Liabilities	3	4
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	1,217	736
Contract Assets	38	63
Contract Liabilities	25	14
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	95	73
Contract Assets	0	0
Contract Liabilities	4	0
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	278	149
Contract Assets	0	1
Contract Liabilities	1	1
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Accounts Receivable	504	753
Contract Assets	0	0
Contract Liabilities	$ 0	$ 0