Introduction - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,053	$ 1,917
Restricted cash:
Total cash, cash equivalents, and restricted cash	1,217	2,037	$ 1,673	$ 1,829
Other current assets
Restricted cash:
Restricted cash	117	62
Other deferred charges and assets
Restricted cash:
Restricted cash	47	58
GEORGIA POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	0	364
Restricted cash:
Total cash, cash equivalents, and restricted cash	160	480	26	33
GEORGIA POWER CO | Other current assets
Restricted cash:
Restricted cash	115	60
GEORGIA POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	45	56
GEORGIA POWER CO | Proceeds From Issuance Of Solid Waste Disposal Facility Revenue Bonds
Restricted cash:
Restricted cash	116	116
GEORGIA POWER CO | Funds From Georgia Housing And Finance Authority
Restricted cash:
Restricted cash	44
SOUTHERN POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	123	131
Restricted cash:
Total cash, cash equivalents, and restricted cash	126	133	139	135
SOUTHERN POWER CO | Other current assets
Restricted cash:
Restricted cash	0	0
SOUTHERN POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	3	3
SOUTHERN POWER CO | Estimated Construction Completion Costs | Deuel Harvest
Restricted cash:
Restricted cash	3	3
SOUTHERN Co GAS
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	88	81
Restricted cash:
Total cash, cash equivalents, and restricted cash	89	83	$ 33	$ 48
SOUTHERN Co GAS | Other current assets
Restricted cash:
Restricted cash	2	2
SOUTHERN Co GAS | Other deferred charges and assets
Restricted cash:
Restricted cash	$ 0	$ 0