REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
	Mar. 17, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 5,493	$ 3,838
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 1,481	810
Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		28 years
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 4,252	3,507
Costs recovered annually		12	2	$ 2
Recoveries for storm damage		$ 213
Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		32 years
Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 136	64
Regulatory asset amortization period	4 years
Regulatory liability amortization period	3 years
Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		8 years
Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (1,925)	(1,874)
Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		7 years
Deferred Income Tax Credits
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (6,016)	(6,301)
Deferred Income Tax Credits | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(2,016)	(1,960)
Deferred Income Tax Credits | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(2,805)	(3,078)
Deferred Income Tax Credits | Georgia Power | Plant Vogtle Units 3 And 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities		440
Deferred Income Tax Credits | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(320)	(358)
Regulatory liabilities		74
Deferred Income Tax Credits | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities		$ 66
Regulatory liability amortization period		3 years
Deferred Income Tax Credits | Mississippi Power | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities		$ 9
Regulatory liability amortization period		2 years
Deferred Income Tax Credits | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (847)	(874)
Other Cost of Removal Obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1,999)	(2,084)
Other Cost of Removal Obligations | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(335)	(412)
Other Cost of Removal Obligations | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		212	156
Other Cost of Removal Obligations | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(194)	(189)
Other Cost of Removal Obligations | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1,649)	(1,606)
Over Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(185)	(205)
Over Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (46)	(112)
Regulatory liability amortization period		9 years
Over Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (44)	(10)
Regulatory liability amortization period		2 years
Over Recovered Regulatory Clause Revenues | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 0	0
Over Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (95)	(82)
Regulatory liability amortization period		5 years
Storm/Property Damage Reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (81)	(204)
Storm/Property Damage Reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(77)	(150)
Storm/Property Damage Reserves | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Storm/Property Damage Reserves | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(4)	(55)
Storm/Property Damage 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		(56)	(285)
Customer Refunds | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(50)	(56)
Regulatory liabilities		50	53
Customer Refunds | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(6)	(229)
Regulatory liabilities			110
Customer Refunds | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Customer Refunds | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Other Regulatory Liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(149)	(70)
Other Regulatory Liabilities | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (37)	(19)
Regulatory liability amortization period		17 years
Other Regulatory Liabilities | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (30)	(6)
Regulatory liability amortization period		12 years
Other Regulatory Liabilities | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (6)	(10)
Regulatory liability amortization period		3 years
Other Regulatory Liabilities | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (54)	(22)
Regulatory liability amortization period		20 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		$ 8
Tax Reform Settlement Agreement | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities			105
AROs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		5,147	4,381
AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 1,470	1,043
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		$ 3,457	3,119
AROs | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		60 years
AROs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 212	210
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
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		$ 4,958	4,423
Retiree Benefit Plans | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 1,265	1,131
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		$ 1,647	1,516
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		$ 238	213
Retiree Benefit Plans | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		14 years
Retiree Benefit Plans | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 187	167
Retiree Benefit Plans | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		13 years
Remaining Net Book Value of Retired Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 1,183	1,275
Remaining Net Book Value of Retired Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		632	649
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		$ 585
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		17 years
Remaining Net Book Value of Retired Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 527	$ 596
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		503
Remaining Net Book Value of Retired Assets | Georgia Power | Plant McIntosh Unit 1 and Plant Mitchell Unit 3
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 24
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period			3 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		15 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		2 years
Remaining Net Book Value of Retired Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 24	$ 30
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]
Total regulatory assets (liabilities), net		$ 11
Regulatory asset amortization period		4 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]
Total regulatory assets (liabilities), net		$ 13
Regulatory asset amortization period		10 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
Deferred Income Tax Charges
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		801	803
Deferred Income Tax Charges | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		235	245
Deferred Income Tax Charges | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		531	523
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 And 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset		145
Deferred Income Tax Charges | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		32	33
Deferred Income Tax Charges | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Environmental Remediation
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		310	349
Environmental Remediation | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Environmental Remediation | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		41	52
Environmental Remediation | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Environmental Remediation | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		269	296
Loss on Reacquired Debt
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		304	323
Loss on Reacquired Debt | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		47	52
Loss on Reacquired Debt | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		248	262
Loss on Reacquired Debt | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		6	6
Loss on Reacquired Debt | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		3	4
Storm Damage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		262	410
Storm Damage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Storm Damage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		262	410
Storm Damage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Storm Damage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Vacation Pay
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 207	186
Regulatory asset amortization period		1 year
Vacation Pay | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 80	72
Vacation Pay | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		104	93
Vacation Pay | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		10	9
Vacation Pay | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		13	11
Under Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		185	159
Under Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 58	40
Regulatory asset amortization period		9 years
Under Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 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		$ 52	47
Under Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 75	72
Regulatory asset amortization period		5 years
Regulatory Clauses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 142	142
Regulatory Clauses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		142	142
Regulatory Clauses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Regulatory Clauses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Regulatory Clauses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Nuclear Outage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		101	105
Nuclear Outage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 61	78
Regulatory asset amortization period		18 months
Nuclear Outage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 40	27
Nuclear Outage | Georgia Power | Maximum
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
Nuclear Outage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 0	0
Fuel Hedging (Realized And Unrealized) Losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net			102
Fuel Hedging (Realized And Unrealized) Losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net			22
Regulatory asset amortization period		3 years 6 months
Fuel Hedging (Realized And Unrealized) Losses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net			53
Regulatory asset amortization period		3 years
Fuel Hedging (Realized And Unrealized) Losses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net			27
Regulatory asset amortization period		5 years
Fuel Hedging (Realized And Unrealized) Losses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net			0
Long Term Debt Fair Value Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 92	107
Long Term Debt Fair Value Adjustment | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		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
Long Term Debt Fair Value Adjustment | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Long Term Debt Fair Value Adjustment | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 92	107
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		18 years
Kemper County energy facility assets, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 50	61
Kemper County energy facility assets, net | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		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
Kemper County energy facility assets, net | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		50	61
Regulatory asset		62
Regulatory liabilities		12
Kemper County energy facility assets, net | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset		50
Regulatory liabilities		12
Kemper County energy facility assets, net | Mississippi Power | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset		12
Kemper County energy facility assets, net | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Plant Daniel Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		32	34
Plant Daniel Units 3 and 4 | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		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
Plant Daniel Units 3 and 4 | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		32	34
Plant Daniel Units 3 and 4 | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		205	127
Other Regulatory Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 52	45
Regulatory asset amortization period		23 years
Other Regulatory Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 68	23
Regulatory asset amortization period		3 years
Other Regulatory Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 4	6
Regulatory asset amortization period		4 years
Other Regulatory Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 81	$ 53
Regulatory asset amortization period		20 years
CCR AROs | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		3 years
Retiree Medicare Drug Subsidy | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 8
Retiree Medicare Drug Subsidy | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		9
Retiree Medicare Drug Subsidy | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		1
Regulatory Clauses, Amortized Through PEP | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 37
Regulatory asset amortization period		4 years
Ad Valorem Tax Adjustment Clause | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 15