Segment and Related Information - Schedule of Traditional Electric Companies (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026 USD ($)	Mar. 31, 2026 USD ($)	Jun. 30, 2025 USD ($)	Mar. 31, 2025 USD ($)	Jun. 30, 2026 USD ($) segment	Jun. 30, 2025 USD ($)
Segment Reporting [Line Items]
Total operating revenues	$ 6,977		$ 6,973		$ 15,374	$ 14,748
Utility operations and maintenance
Total utility operations and maintenance	1,705		1,685		3,359	3,305
Other segment items	3,472		3,617		8,138	7,812
Depreciation and amortization(b)	1,434		1,323		2,854	2,608
Interest expense(d)	796		874		1,573	1,588
Income taxes (benefit)	187		289		414	569
Consolidated Net Income Attributable to Southern Company	1,174		880		$ 2,531	2,214
Traditional Electric Operating Companies
Utility operations and maintenance
Number of reportable segments \| segment					1
ALABAMA POWER CO
Segment Reporting [Line Items]
Total operating revenues	1,963		1,968		$ 4,055	3,980
Utility operations and maintenance
Total utility operations and maintenance	415		472		808	935
Depreciation and amortization(b)	385		371		766	741
Interest expense(d)	117		116		232	225
Income taxes (benefit)	135		115		263	226
Consolidated Net Income Attributable to Southern Company	437	$ 425	381	$ 375	862	755
GEORGIA POWER CO
Segment Reporting [Line Items]
Total operating revenues	3,133		3,110		6,276	6,148
Utility operations and maintenance
Total utility operations and maintenance	667		645		1,341	1,283
Depreciation and amortization(b)	503		512		987	1,015
Interest expense(d)	228		198		431	385
Income taxes (benefit)	151		236		236	334
Consolidated Net Income Attributable to Southern Company	779	628	607	596	1,408	1,204
MISSISSIPPI POWER CO
Segment Reporting [Line Items]
Total operating revenues	403		400		875	821
Utility operations and maintenance
Total utility operations and maintenance	107		82		194	166
Depreciation and amortization(b)	58		52		113	105
Interest expense(d)	21		20		41	40
Income taxes (benefit)	16		17		34	34
Consolidated Net Income Attributable to Southern Company	52	$ 60	59	$ 55	112	114
SOUTHERN POWER CO
Segment Reporting [Line Items]
Total operating revenues	535		546		1,216	1,113
Utility operations and maintenance
Total utility operations and maintenance	139		135		278	257
Depreciation and amortization(b)	280		177		558	329
Interest expense(d)	28		24		55	50
Income taxes (benefit)	(77)		(2)		(147)	(3)
Consolidated Net Income Attributable to Southern Company	(25)		51		$ (22)	138
Number of reportable segments \| segment					1
Reportable Segment \| ALABAMA POWER CO
Segment Reporting [Line Items]
Total operating revenues	1,963		1,968		$ 4,055	3,980
Utility operations and maintenance
Rate RSE expenses	332		374		633	739
Rate CNP Compliance expenses	71		67		145	142
Total utility operations and maintenance	403		441		778	881
Other segment items	486		544		1,154	1,152
Depreciation and amortization(b)	385		371		766	741
Interest expense(d)	117		116		232	225
Income taxes (benefit)	135		115		263	226
Consolidated Net Income Attributable to Southern Company	437		381		862	755
Capital expenditures	501		599		1,019	1,159
Reportable Segment \| GEORGIA POWER CO
Segment Reporting [Line Items]
Total operating revenues	3,133		3,110		6,276	6,148
Utility operations and maintenance
Total utility operations and maintenance	586		568		1,164	1,104
Other segment items	886		989		2,050	2,106
Depreciation and amortization(b)	503		512		987	1,015
Interest expense(d)	228		198		431	385
Income taxes (benefit)	151		236		236	334
Consolidated Net Income Attributable to Southern Company	779		607		1,408	1,204
Capital expenditures	2,173		1,676		4,243	3,313
Reportable Segment \| MISSISSIPPI POWER CO
Segment Reporting [Line Items]
Total operating revenues	403		400		875	821
Operational expenses	80		65		144	122
Environmental compliance expenses	3		4		7	6
Utility operations and maintenance
Other segment items	173		183		424	400
Depreciation and amortization(b)	58		52		113	105
Interest expense(d)	21		20		41	40
Income taxes (benefit)	16		17		34	34
Consolidated Net Income Attributable to Southern Company	52		59		112	114
Capital expenditures	96		126		178	199
Reportable Segment \| SOUTHERN POWER CO
Segment Reporting [Line Items]
Total operating revenues	535		546		1,216	1,113
Utility operations and maintenance
Other segment items	329		296		772	599
Depreciation and amortization(b)	280		177		558	329
Interest expense(d)	28		24		55	50
Income taxes (benefit)	(77)		(2)		(147)	(3)
Consolidated Net Income Attributable to Southern Company	$ (25)		$ 51		$ (22)	$ 138
Traditional Electric Operating Companies
Utility operations and maintenance
Number of reportable segments \| segment					1

The current period expense charged against earnings on long-lived, physical assets used in the normal conduct of business and not intended for resale to allocate or recognize the cost of assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset. Excludes amortization of nuclear fuel.

No definition available.