Introduction - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,152	$ 748
Restricted cash:
Total cash, cash equivalents, and restricted cash	1,211	921	$ 2,244	$ 2,037
Other current assets
Restricted cash:
Restricted cash	46	141
Other deferred charges and assets
Restricted cash:
Restricted cash	14	31
ALABAMA POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	287	324
Restricted cash:
Total cash, cash equivalents, and restricted cash	289	409	321	687
ALABAMA POWER CO | Other current assets
Restricted cash:
Restricted cash	2	85
ALABAMA POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	0	0
GEORGIA POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	68	9
Restricted cash:
Total cash, cash equivalents, and restricted cash	107	75	160	480
GEORGIA POWER CO | Other current assets
Restricted cash:
Restricted cash	26	37
GEORGIA POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	14	29
SOUTHERN POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	145	124
Restricted cash:
Total cash, cash equivalents, and restricted cash	162	144	172	133
SOUTHERN POWER CO | Other current assets
Restricted cash:
Restricted cash	17	17
SOUTHERN POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	0	3
SOUTHERN POWER CO | Proceeds From Issuance Of Solid Waste Disposal Facility Revenue Bonds
Restricted cash:
Restricted cash	17	17
SOUTHERN POWER CO | Estimated Construction Completion Costs | Deuel Harvest
Restricted cash:
Restricted cash		3
SOUTHERN Co GAS
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	34	33
Restricted cash:
Total cash, cash equivalents, and restricted cash	35	35	$ 244	$ 83
SOUTHERN Co GAS | Other current assets
Restricted cash:
Restricted cash	1	2
SOUTHERN Co GAS | Other deferred charges and assets
Restricted cash:
Restricted cash	$ 0	$ 0