Introduction - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Other intangible assets subject to amortization:
Gross Carrying Amount	$ 676	$ 677
Accumulated Amortization	(326)	(307)
Other Intangible Assets, Net	350	370
Other intangible assets not subject to amortization:
Federal Communications Commission licenses	75	75
Total other intangible assets
Gross Carrying Amount	751	752
Accumulated Amortization	(326)	(307)
Other Intangible Assets, Net	425	445
Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	212	212
Accumulated Amortization	(157)	(150)
Other Intangible Assets, Net	55	62
Total other intangible assets
Accumulated Amortization	(157)	(150)
Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	64	64
Accumulated Amortization	(41)	(38)
Other Intangible Assets, Net	23	26
Total other intangible assets
Accumulated Amortization	(41)	(38)
PPA fair value adjustments
Other intangible assets subject to amortization:
Gross Carrying Amount	390	390
Accumulated Amortization	(119)	(109)
Other Intangible Assets, Net	271	281
Total other intangible assets
Accumulated Amortization	(119)	(109)
Other
Other intangible assets subject to amortization:
Gross Carrying Amount	10	11
Accumulated Amortization	(9)	(10)
Other Intangible Assets, Net	1	1
Total other intangible assets
Accumulated Amortization	(9)	(10)
SOUTHERN POWER CO
Other intangible assets subject to amortization:
Accumulated Amortization	(119)	(109)
Total other intangible assets
Accumulated Amortization	(119)	(109)
SOUTHERN POWER CO | PPA fair value adjustments
Other intangible assets subject to amortization:
Gross Carrying Amount	390	390
Accumulated Amortization	(119)	(109)
Other Intangible Assets, Net	271	281
Total other intangible assets
Accumulated Amortization	(119)	(109)
SOUTHERN Co GAS
Other intangible assets subject to amortization:
Gross Carrying Amount	182	182
Accumulated Amortization	(151)	(145)
Other Intangible Assets, Net	31	37
Total other intangible assets
Accumulated Amortization	(151)	(145)
Other Intangible Assets, Net	31	37
SOUTHERN Co GAS | Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	156	156
Accumulated Amortization	(135)	(130)
Other Intangible Assets, Net	21	26
Total other intangible assets
Accumulated Amortization	(135)	(130)
SOUTHERN Co GAS | Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	26	26
Accumulated Amortization	(16)	(15)
Other Intangible Assets, Net	10	11
Total other intangible assets
Accumulated Amortization	$ (16)	$ (15)