REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions			12 Months Ended				36 Months Ended
	Jan. 01, 2023	Dec. 06, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 5,833	$ 4,711		$ 5,833
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				2,340	1,217		2,340
Customer refund		$ 318
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				4,663	3,928		4,663
Costs recovered annually				12	12	$ 12
Storm damage reserves							213
Georgia Power | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Costs recovered annually			$ 5
Storm damage reserves	$ 31
Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				4	46		4
Regulatory asset amortization period						4 years
Regulatory liability amortization period						3 years
Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,891)	(1,471)		(1,891)
Deferred Income Tax Credits
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(5,251)	(5,636)		(5,251)
Deferred Income Tax Credits | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,925)	(1,968)		(1,925)
Deferred Income Tax Credits | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(2,244)	(2,537)		(2,244)
Deferred Income Tax Credits | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(269)	(288)		(269)
Regulatory liabilities				$ 33			33
Deferred Income Tax Credits | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years
Deferred Income Tax Credits | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (788)	(816)		(788)
Other Cost of Removal Obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,430)	(1,826)		(1,430)
Other Cost of Removal Obligations | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				11	(192)		11
Other Cost of Removal Obligations | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				462	278		462
Other Cost of Removal Obligations | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(196)	(195)		(196)
Other Cost of Removal Obligations | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,707)	(1,683)		(1,707)
Storm/Property Damage Reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(216)	(133)		(216)
Storm/Property Damage Reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(97)	(103)		(97)
Storm/Property Damage Reserves | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(83)	0		(83)
Storm/Property Damage Reserves | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(36)	(30)		(36)
Storm/Property Damage Reserves | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Fuel Hedging (Realized And Unrealized) gains
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(83)			(83)
Fuel Hedging (Realized And Unrealized) gains | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(38)			(38)
Fuel Hedging (Realized And Unrealized) gains | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(21)			(21)
Fuel Hedging (Realized And Unrealized) gains | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(24)			(24)
Fuel Hedging (Realized And Unrealized) gains | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Reliability reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(191)			(191)
Reliability reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(166)			(166)
Reliability reserves | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Reliability reserves | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(25)			(25)
Reliability reserves | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Customer Refunds
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(183)	(189)		(183)
Customer Refunds | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(62)	(181)		(62)
Regulatory liabilities				62	181		62
Customer Refunds | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(121)	(8)		(121)
Regulatory liabilities				119	5		119
Customer Refunds | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Customer Refunds | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Over Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(64)	(63)		(64)
Over Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	(1)		0
Over Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(38)	(59)		(38)
Over Recovered Regulatory Clause Revenues | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Over Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (26)	(3)		(26)
Regulatory liability amortization period				5 years
Other Regulatory Liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (239)	(121)		(239)
Other Regulatory Liabilities | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (40)	(29)		(40)
Regulatory liability amortization period				11 years
Other Regulatory Liabilities | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (21)	(24)		(21)
Regulatory liability amortization period				10 years
Other Regulatory Liabilities | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (3)	(4)		(3)
Regulatory liability amortization period				4 years
Other Regulatory Liabilities | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (93)	(57)		(93)
Regulatory liability amortization period				20 years
Fuel Hedging (Realized And Unrealized) losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years 6 months
Fuel Hedging (Realized And Unrealized) losses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				4 years
Excess Deferred Income Tax Liabilities Not Subject to Normalization | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1			1
AROs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				6,096	5,685		6,096
AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1,971	1,576		1,971
AROs | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				53 years
AROs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 3,829	3,866		3,829
AROs | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				57 years
AROs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 242	236		242
AROs | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				55 years
AROs | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
AROs | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				80 years
Retiree Benefit Plans
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 2,517	2,998		2,517
Retiree Benefit Plans | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 675	747		675
Retiree Benefit Plans | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 848	962		848
Retiree Benefit Plans | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 113	145		113
Retiree Benefit Plans | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 114	95		114
Retiree Benefit Plans | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				14 years
Remaining Net Book Value of Retired Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1,543	1,050		1,543
Remaining Net Book Value of Retired Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				562	574		562
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 492			492
Remaining Net Book Value of Retired Assets | Alabama Power | Maximum | Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				15 years
Remaining Net Book Value of Retired Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 962	$ 455		962
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Wansley Units 1 and 2
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 562			562
Regulatory asset amortization period				8 years
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 396			396
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				3 years	4 years
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Remaining Net Book Value of Retired Assets | Georgia Power | Minimum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				1 year
Remaining Net Book Value of Retired Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 19	$ 21		19
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				10 years
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				14 years
Remaining Net Book Value of Retired Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Under Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				953	806		953
Under Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 788	225		788
Under Recovered Regulatory Clause Revenues | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				8 years
Under Recovered Regulatory Clause Revenues | Alabama Power | Minimum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				2 years
Under Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Regulatory asset amortization period				2 years
Under Recovered Regulatory Clause Revenues | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 31	49		31
Under Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 134	532		134
Regulatory asset amortization period				5 years
Deferred Income Tax Charges
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 866	829		866
Deferred Income Tax Charges | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				250	240		250
Deferred Income Tax Charges | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				583	555		583
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				145			145
Deferred Income Tax Charges | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				30	31		30
Deferred Income Tax Charges | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				294	302		294
Environmental Remediation | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				25	35		25
Environmental Remediation | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				269	267		269
Loss on Reacquired Debt
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				257	281		257
Loss on Reacquired Debt | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 38	42		38
Loss on Reacquired Debt | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				25 years
Loss on Reacquired Debt | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 213	231		213
Loss on Reacquired Debt | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				30 years
Loss on Reacquired Debt | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 5	6		5
Loss on Reacquired Debt | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				19 years
Loss on Reacquired Debt | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1	2		1
Loss on Reacquired Debt | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				5 years
Vacation Pay
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 212	207		212
Regulatory asset amortization period				1 year
Vacation Pay | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 82	81		82
Vacation Pay | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				108	102		108
Vacation Pay | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				10	10		10
Vacation Pay | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				12	14		12
Regulatory Clauses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 142	142		142
Costs recovered annually, period of recovery				8 years
Regulatory Clauses | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period	5 years
Regulatory Clauses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 142	142		142
Regulatory Clauses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Regulatory Clauses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Regulatory Clauses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Software and Cloud Computing Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 111	73		111
Regulatory asset amortization period				5 years
Software and Cloud Computing Costs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 46	35		46
Regulatory asset amortization period				10 years
Software and Cloud Computing Costs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 59	33		59
Software and Cloud Computing Costs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Software and Cloud Computing Costs | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 6	5		6
Regulatory asset amortization period				10 years
Nuclear Outage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 82	75		82
Nuclear Outage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 52	41		52
Nuclear Outage | Alabama Power | Plant Farley
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				18 months
Nuclear Outage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 30	34		30
Nuclear Outage | Georgia Power | Maximum | Plant Hatch (nuclear)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				24 months
Nuclear Outage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Nuclear Outage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				69	79		69
Long Term Debt Fair Value Adjustment | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 69	79		69
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				16 years
Fuel Hedging (Realized And Unrealized) losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 60	(176)		60
Fuel Hedging (Realized And Unrealized) losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				15	(50)		15
Fuel Hedging (Realized And Unrealized) losses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				45	(72)		45
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	(54)		0
Fuel Hedging (Realized And Unrealized) losses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Storm Damage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				44	97		44
Storm Damage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Storm Damage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	48		0
Storm Damage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				44	49		44
Storm Damage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				27	28		27
Plant Daniel Units 3 and 4 | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				18			18
Plant Daniel Units 3 and 4 | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				9			9
Plant Daniel Units 3 and 4 | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4 | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4 | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				27	28		27
Plant Daniel Units 3 and 4 | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				20	35		20
Kemper County energy facility assets, net | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				20	35		20
Regulatory asset				26			26
Regulatory liabilities				6			6
Kemper County energy facility assets, net | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				17			17
Regulatory liabilities				6			6
Kemper County energy facility assets, net | Mississippi Power | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				10			10
Kemper County energy facility assets, net | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				197	168		197
Other Regulatory Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 36	38		36
Regulatory asset amortization period				21 years
Other Regulatory Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 27	29		27
Regulatory asset amortization period				10 years
Other Regulatory Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 16	7		16
Regulatory asset amortization period				14 years
Other Regulatory Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 118	$ 94		118
Regulatory asset amortization period				20 years
CCR AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				38 years
CCR AROs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				3 years
CCR AROs | Georgia Power | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period	4 years
Regulatory Clauses, Amortized Through PEP | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 12			12
Regulatory asset amortization period				3 years
Ad Valorem Tax Adjustment Clause | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 18			$ 18