Revenue from Contracts with Customers and Lease Income - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 3,090	$ 2,820
Contract Assets	304	271
Contract Liabilities	235	116
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	864	821
Contract Assets	0	2
Contract Liabilities	2	0
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	1,448	1,011
Contract Assets	130	121
Contract Liabilities	42	1
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	102	90
Contract Assets	0	0
Contract Liabilities	0	0
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	141	122
Contract Assets	0	0
Contract Liabilities	1	4
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Accounts Receivable	387	684
Contract Assets	67	56
Contract Liabilities	$ 0	$ 0