REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 4,711	$ 5,493
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		1,217	1,481
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		3,928	4,252
Costs recovered annually		12	12	$ 2
Storm damage reserves		213
Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		46	136
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		(1,471)	(1,925)
Deferred Income Tax Credits
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(5,636)	(6,016)
Deferred Income Tax Credits | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1,968)	(2,016)
Deferred Income Tax Credits | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(2,537)	(2,805)
Deferred Income Tax Credits | Georgia Power | Plant Vogtle Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liabilities		220
Deferred Income Tax Credits | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(288)	(320)
Regulatory liabilities		$ 46
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		$ (816)	(847)
Other Cost of Removal Obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1,826)	(1,999)
Other Cost of Removal Obligations | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(192)	(335)
Other Cost of Removal Obligations | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		278	212
Other Cost of Removal Obligations | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(195)	(194)
Other Cost of Removal Obligations | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1,683)	(1,649)
Customer Refunds
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(189)	(56)
Customer Refunds | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(181)	(50)
Regulatory liabilities		181	50
Customer Refunds | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(8)	(6)
Regulatory liabilities			5
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
Fuel Hedging (Realized And Unrealized) Losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(176)
Fuel Hedging (Realized And Unrealized) Losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (50)
Regulatory liability 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		$ (72)
Regulatory liability 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		$ (54)
Regulatory liability amortization period		3 years
Fuel Hedging (Realized And Unrealized) Losses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 0
Storm/Property Damage Reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(133)	(81)
Storm/Property Damage Reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(103)	(77)
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		(30)	(4)
Storm/Property Damage Reserves | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Over Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(63)	(185)
Over Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(1)	(46)
Over Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		(59)	(44)
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		$ (3)	(95)
Regulatory liability amortization period		4 years
Other Regulatory Liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (121)	(149)
Other Regulatory Liabilities | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (29)	(37)
Regulatory liability amortization period		16 years
Other Regulatory Liabilities | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (24)	(30)
Regulatory liability amortization period		11 years
Other Regulatory Liabilities | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ (4)	(6)
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		$ (57)	(54)
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		$ 3
AROs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		5,685	5,147
AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 1,576	1,470
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		$ 3,866	3,457
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		$ 236	212
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		$ 2,998	4,958
Retiree Benefit Plans | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 747	1,265
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		$ 962	1,647
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		$ 145	238
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		$ 95	187
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		$ 1,050	1,183
Remaining Net Book Value of Retired Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		574	632
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		$ 533
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		16 years
Remaining Net Book Value of Retired Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 455	527
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		445
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		$ 10
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		14 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		$ 21	24
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		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		829	801
Deferred Income Tax Charges | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		240	235
Deferred Income Tax Charges | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		555	531
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		31	32
Deferred Income Tax Charges | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Under Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		806	185
Under Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 225	58
Regulatory asset amortization period		8 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		$ 49	52
Under Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 532	75
Regulatory asset amortization period		4 years
Environmental Remediation
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 302	310
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		35	41
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		267	269
Loss on Reacquired Debt
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		281	304
Loss on Reacquired Debt | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 42	47
Loss on Reacquired Debt | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		26 years
Loss on Reacquired Debt | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 231	248
Loss on Reacquired Debt | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		31 years
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 | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		20 years
Loss on Reacquired Debt | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 2	3
Loss on Reacquired Debt | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		6 years
Vacation Pay
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 207	207
Regulatory asset amortization period		1 year
Vacation Pay | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 81	80
Vacation Pay | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		102	104
Vacation Pay | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		10	10
Vacation Pay | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		14	13
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
Storm Damage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		97	262
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		48	262
Storm Damage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		49	0
Storm Damage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Long Term Debt Fair Value Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		79	92
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		$ 79	92
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period		17 years
Nuclear Outage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 75	101
Nuclear Outage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 41	61
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		$ 34	40
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
Nuclear Outage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Software and Cloud Computing Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		73	31
Software and Cloud Computing Costs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 35	17
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		$ 33	12
Software and Cloud Computing Costs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		0	0
Software and Cloud Computing Costs | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 5	2
Regulatory asset amortization period		10 years
Kemper County energy facility assets, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 35	50
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		35	50
Regulatory asset		44
Regulatory liabilities		9
Kemper County energy facility assets, net | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset		33
Regulatory liabilities		9
Kemper County energy facility assets, net | Mississippi Power | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset		11
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		28	32
Plant Daniel Units 3 and 4 | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		19
Plant Daniel Units 3 and 4 | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		9
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		28	32
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		168	174
Other Regulatory Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 38	35
Regulatory asset amortization period		23 years
Other Regulatory Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 29	56
Regulatory asset amortization period		10 years
Other Regulatory Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 7	4
Regulatory asset amortization period		6 years
Other Regulatory Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 94	$ 79
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		$ 7
Retiree Medicare Drug Subsidy | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		4
Regulatory Clauses, Amortized Through PEP | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net		$ 24
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		$ 25