SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Schedule of costs for affiliate transactions

Costs for these services from SCS in 2021, 2020, and 2019 were as follows:

	Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
2021	$	504	$	663	$	120	$	89	$	239
2020	478		639		149		87		237
2019	527		704		118		90		183

Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows:

	Mississippi Power		Southern Power
	(in millions)
2021	$	9	$	15
2020	4		8
2019	3		14

Transportation costs under these agreements in 2021, 2020, and 2019 were as follows:

	Alabama Power		Georgia Power		Southern Power		Southern Company Gas
	(in millions)
2021	$	14	$	108	$	31	$	29
2020	15		108		29		29
2019	17		99		28		31

The approximate rates for 2021, 2020, and 2019 are as follows:

	2021		2020		2019
Alabama Power	2.7	%	2.6	%	3.1	%
Georgia Power	3.3	%	3.0	%	2.6	%
Mississippi Power	3.6	%	3.7	%	3.7	%
Southern Company Gas	2.8	%	2.8	%	2.9	%

Schedule of total AFUDC and interest capitalized

Total AFUDC and interest capitalized for the Registrants in 2021, 2020, and 2019 was as follows:

	Southern Company		Alabama Power		Georgia Power(*)		Mississippi Power		Southern Power		Southern Company Gas
	(in millions)
2021	$	282	$	68	$	190	$	—	$	6	$	18
2020	230		61		138		1		11		18
2019	202		71		103		—		15		13

(*)See Note 2 under "Georgia Power – Nuclear Construction" for information on the inclusion of a portion of construction costs related to Plant Vogtle Units 3 and 4 in Georgia Power's rate base.

Schedule of average AFUDC composite rates

The average AFUDC composite rates for 2021, 2020, and 2019 for the traditional electric operating companies and the natural gas distribution utilities were as follows:

	2021		2020		2019
Alabama Power	7.9	%	8.1	%	8.4	%
Georgia Power(*)	7.2	%	6.9	%	6.9	%
Mississippi Power	2.5	%	5.4	%	7.3	%
Southern Company Gas:
Atlanta Gas Light	7.7	%	7.7	%	7.8	%
Chattanooga Gas	7.1	%	7.1	%	7.1	%
Nicor Gas	0.1	%	0.7	%	2.3	%

(*)Excludes AFUDC related to the construction of Plant Vogtle Units 3 and 4. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.

Schedule of goodwill balances

At December 31, 2021 and 2020, goodwill was as follows:

	Goodwill
	(in millions)
Southern Company	$	5,280
Southern Company Gas:
Gas distribution operations	$	4,034
Gas marketing services	981
Southern Company Gas total	$	5,015

Schedule of intangible assets subject to amortization

At December 31, 2021 and 2020, other intangible assets were as follows:

	At December 31, 2021						At December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Other Intangible Assets, Net		Gross Carrying Amount		Accumulated Amortization		Other Intangible Assets, Net
	(in millions)						(in millions)
Southern Company
Other intangible assets subject to amortization:
Customer relationships	$	212	$	(150)	$	62	$	212	$	(135)	$	77
Trade names	64		(38)		26		64		(31)		33
Storage and transportation contracts(*)	—		—		—		64		(64)		—
PPA fair value adjustments	390		(109)		281		390		(89)		301
Other	11		(10)		1		10		(9)		1
Total other intangible assets subject to amortization	$	677	$	(307)	$	370	$	740	$	(328)	$	412
Other intangible assets not subject to amortization:
Federal Communications Commission licenses	75		—		75		75		—		75
Total other intangible assets	$	752	$	(307)	$	445	$	815	$	(328)	$	487
Southern Power
Other intangible assets subject to amortization:
PPA fair value adjustments	$	390	$	(109)	$	281	$	390	$	(89)	$	301
Southern Company Gas
Other intangible assets subject to amortization:
Gas marketing services
Customer relationships	$	156	$	(130)	$	26	$	156	$	(119)	$	37
Trade names	26		(15)		11		26		(12)		14
Wholesale gas services
Storage and transportation contracts(*)	—		—		—		64		(64)		—
Total other intangible assets subject to amortization	$	182	$	(145)	$	37	$	246	$	(195)	$	51

(*)See Note 15 under "Southern Company Gas" for information regarding the sale of Sequent.

Schedule of intangible assets not subject to amortization

At December 31, 2021 and 2020, other intangible assets were as follows:

	At December 31, 2021						At December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Other Intangible Assets, Net		Gross Carrying Amount		Accumulated Amortization		Other Intangible Assets, Net
	(in millions)						(in millions)
Southern Company
Other intangible assets subject to amortization:
Customer relationships	$	212	$	(150)	$	62	$	212	$	(135)	$	77
Trade names	64		(38)		26		64		(31)		33
Storage and transportation contracts(*)	—		—		—		64		(64)		—
PPA fair value adjustments	390		(109)		281		390		(89)		301
Other	11		(10)		1		10		(9)		1
Total other intangible assets subject to amortization	$	677	$	(307)	$	370	$	740	$	(328)	$	412
Other intangible assets not subject to amortization:
Federal Communications Commission licenses	75		—		75		75		—		75
Total other intangible assets	$	752	$	(307)	$	445	$	815	$	(328)	$	487
Southern Power
Other intangible assets subject to amortization:
PPA fair value adjustments	$	390	$	(109)	$	281	$	390	$	(89)	$	301
Southern Company Gas
Other intangible assets subject to amortization:
Gas marketing services
Customer relationships	$	156	$	(130)	$	26	$	156	$	(119)	$	37
Trade names	26		(15)		11		26		(12)		14
Wholesale gas services
Storage and transportation contracts(*)	—		—		—		64		(64)		—
Total other intangible assets subject to amortization	$	182	$	(145)	$	37	$	246	$	(195)	$	51

(*)See Note 15 under "Southern Company Gas" for information regarding the sale of Sequent.

Schedule of amortization associated with other intangible assets

Amortization associated with other intangible assets in 2021, 2020, and 2019 was as follows:

	2021		2020		2019
	(in millions)
Southern Company(a)	$	44	$	49	$	61
Southern Power(b)	20		20		19
Southern Company Gas:
Gas marketing services	$	15	$	17	$	23
Wholesale gas services(b)	—		2		8
Southern Company Gas total	$	15	$	19	$	31

(a)Includes $20 million, $22 million, and $27 million in 2021, 2020, and 2019, respectively, recorded as a reduction to operating revenues.

(b)Recorded as a reduction to operating revenues.

Schedule of estimated future amortization of other intangible assets

At December 31, 2021, the estimated amortization associated with other intangible assets for the next five years is as follows:

	2022		2023		2024		2025		2026
	(in millions)
Southern Company	$	39	$	37	$	35	$	32	$	27
Southern Power	20		20		20		20		20
Southern Company Gas	11		9		7		6		3

Schedule of cash, cash equivalents, and restricted cash

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants:

	Southern Company				Southern Power		Southern Company Gas
	December 31, 2021		December 31, 2020		December 31, 2021		December 31, 2021		December 31, 2020
	(in millions)				(in millions)		(in millions)
Cash and cash equivalents	$	1,798	$	1,065	$	107	$	45	$	17
Restricted cash(a):
Other current assets	2		2		—		2		2
Other deferred charges and assets	29		—		29		—		—
Total cash, cash equivalents, and restricted cash(b)	$	1,829	$	1,068	$	135	$	48	$	19

(a)For Southern Power, reflects restricted cash of $19 million related to tax equity contributions restricted until the Garland battery energy storage facility achieves final contracted capacity and $10 million held to fund estimated construction completion costs at the Deuel Harvest wind facility. See Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects restricted cash held as collateral for workers' compensation, life insurance, and long-term disability insurance.

(b)Total may not add due to rounding.

Reconciliation of restricted cash and cash equivalents

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants:

	Southern Company				Southern Power		Southern Company Gas
	December 31, 2021		December 31, 2020		December 31, 2021		December 31, 2021		December 31, 2020
	(in millions)				(in millions)		(in millions)
Cash and cash equivalents	$	1,798	$	1,065	$	107	$	45	$	17
Restricted cash(a):
Other current assets	2		2		—		2		2
Other deferred charges and assets	29		—		29		—		—
Total cash, cash equivalents, and restricted cash(b)	$	1,829	$	1,068	$	135	$	48	$	19

(a)For Southern Power, reflects restricted cash of $19 million related to tax equity contributions restricted until the Garland battery energy storage facility achieves final contracted capacity and $10 million held to fund estimated construction completion costs at the Deuel Harvest wind facility. See Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects restricted cash held as collateral for workers' compensation, life insurance, and long-term disability insurance.

(b)Total may not add due to rounding.

Schedule of storm damage reserves

In accordance with their respective state PSC orders, the traditional electric operating companies accrued the following amounts related to storm damage recovery in 2021, 2020, and 2019:

	Southern Company(a)(b)		Alabama Power(a)		Georgia Power		Mississippi Power(b)
	(in millions)
2021	$	286	$	75	$	213	$	(2)
2020	326		112		213		1
2019	170		139		30		1

(a)Includes $39 million applied in 2019 to Alabama Power's NDR from its remaining excess deferred income tax regulatory liability balance in accordance with an Alabama PSC order.

(b)Mississippi Power's net accrual includes carrying costs, as well as amortization of related excess deferred income tax benefits.

Schedule of AOCI (loss) balances, net of tax effects

AOCI (loss) balances, net of tax effects, for Southern Company, Southern Power, and Southern Company Gas were as follows:

	Qualifying Hedges		Pension and Other Postretirement Benefit Plans		Accumulated Other Comprehensive Income (Loss)(*)
	(in millions)
Southern Company
Balance at December 31, 2020	$	(209)	$	(187)	$	(395)
Current period change	47		111		158
Balance at December 31, 2021	$	(162)	$	(76)	$	(237)
Southern Power
Balance at December 31, 2020	$	(21)	$	(47)	$	(67)
Current period change	22		18		40
Balance at December 31, 2021	$	1	$	(29)	$	(27)
Southern Company Gas
Balance at December 31, 2020	$	(20)	$	(2)	$	(22)
Current period change	6		40		46
Balance at December 31, 2021	$	(14)	$	38	$	24

(*)May not add due to rounding.