Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value

At March 31, 2023, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows:

	Fair Value Measurements Using:
At March 31, 2023	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Net Asset Value as a Practical Expedient (NAV)		Total
	(in millions)
Southern Company
Assets:
Energy-related derivatives(a)	$	4	$	100	$	—	$	—	$	104
Interest rate derivatives	—		2		—		—		2
Investments in trusts:(b)(c)
Domestic equity	680		192		—		—		872
Foreign equity	138		162		—		—		300
U.S. Treasury and government agency securities	—		316		—		—		316
Municipal bonds	—		48		—		—		48
Pooled funds – fixed income	—		7		—		—		7
Corporate bonds	—		403		—		—		403
Mortgage and asset backed securities	—		90		—		—		90
Private equity	—		—		—		160		160
Cash and cash equivalents	2		—		—		—		2
Other	40		12		—		9		61
Cash equivalents	433		13		—		—		446
Other investments	9		29		8		—		46
Total	$	1,306	$	1,374	$	8	$	169	$	2,857
Liabilities:
Energy-related derivatives(a)	$	40	$	354	$	—	$	—	$	394
Interest rate derivatives	—		261		—		—		261
Foreign currency derivatives	—		218		—		—		218
Contingent consideration	—		—		12		—		12
Other	—		13		—		—		13
Total	$	40	$	846	$	12	$	—	$	898

	Fair Value Measurements Using:
At March 31, 2023	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Net Asset Value as a Practical Expedient (NAV)		Total
	(in millions)
Alabama Power
Assets:
Energy-related derivatives	$	—	$	32	$	—	$	—	$	32
Nuclear decommissioning trusts:(b)
Domestic equity	404		185		—		—		589
Foreign equity	138		—		—		—		138
U.S. Treasury and government agency securities	—		19		—		—		19
Municipal bonds	—		1		—		—		1
Corporate bonds	—		223		—		—		223
Mortgage and asset backed securities	—		22		—		—		22
Private equity	—		—		—		160		160
Other	7		—		—		9		16
Cash equivalents	193		13		—		—		206
Other investments	—		29		—		—		29
Total	$	742	$	524	$	—	$	169	$	1,435
Liabilities:
Energy-related derivatives	$	—	$	96	$	—	$	—	$	96
Georgia Power
Assets:
Energy-related derivatives	$	—	$	22	$	—	$	—	$	22
Nuclear decommissioning trusts:(b)(c)
Domestic equity	276		1		—		—		277
Foreign equity	—		161		—		—		161
U.S. Treasury and government agency securities	—		297		—		—		297
Municipal bonds	—		47		—		—		47
Corporate bonds	—		180		—		—		180
Mortgage and asset backed securities	—		68		—		—		68
Other	33		12		—		—		45
Total	$	309	$	788	$	—	$	—	$	1,097
Liabilities:
Energy-related derivatives	$	—	$	132	$	—	$	—	$	132
Interest rate derivatives	—		1		—		—		1
Total	$	—	$	133	$	—	$	—	$	133

	Fair Value Measurements Using:
At March 31, 2023	Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Net Asset Value as a Practical Expedient (NAV)		Total
	(in millions)
Mississippi Power
Assets:
Energy-related derivatives	$	—	$	35	$	—	$	—	$	35
Cash equivalents	3		—		—		—		3
Total	$	3	$	35	$	—	$	—	$	38
Liabilities:
Energy-related derivatives	$	—	$	62	$	—	$	—	$	62
Southern Power
Assets:
Energy-related derivatives	$	—	$	5	$	—	$	—	$	5
Cash equivalents	13		—		—		—		13
Total	$	13	$	5	$	—	$	—	$	18
Liabilities:
Energy-related derivatives	$	—	$	14	$	—	$	—	$	14
Foreign currency derivatives	—		47		—		—		47
Contingent consideration	—		—		12		—		12
Other	—		13		—		—		13
Total	$	—	$	74	$	12	$	—	$	86
Southern Company Gas
Assets:
Energy-related derivatives(a)	$	4	$	6	$	—	$	—	$	10
Interest rate derivatives	—		1		—		—		1
Non-qualified deferred compensation trusts:
Domestic equity	—		6		—		—		6
Foreign equity	—		1		—		—		1
Pooled funds – fixed income	—		7		—		—		7
Cash equivalents	2		—		—		—		2
Cash equivalents and restricted cash	55		—		—		—		55
Total	$	61	$	21	$	—	$	—	$	82
Liabilities:
Energy-related derivatives(a)	$	40	$	50	$	—	$	—	$	90
Interest rate derivatives	—		72		—		—		72
Total	$	40	$	122	$	—	$	—	$	162

(a)Excludes cash collateral of $60 million.

(b)Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information.

(c)Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. At March 31, 2023, approximately $37 million of the fair market value of Georgia Power's nuclear decommissioning trust funds' securities were on loan to creditors under the funds' managers' securities lending program. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information.

Schedule of Increase (Decrease) In Fair Value Of Funds

The fair value of the funds, including reinvested interest and dividends and excluding the funds' expenses, increased (decreased) by the amounts shown in the table below for the three months ended March 31, 2023 and 2022. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively.

	Three Months Ended
Fair value increases (decreases)	March 31, 2023		March 31, 2022
	(in millions)
Southern Company	$	102	$	(150)
Alabama Power	45		(67)
Georgia Power	57		(83)

Schedule of Financial Instruments for which Carrying Amount Did Not Equal Fair Value

At March 31, 2023, other financial instruments for which the carrying amount did not equal fair value were as follows:

	Southern Company		Alabama Power		Georgia Power		Mississippi Power		Southern Power		Southern Company Gas(*)
	(in billions)
Long-term debt, including securities due within one year:
Carrying amount	$	56.1	$	10.6	$	14.9	$	1.5	$	3.0	$	7.5
Fair value	51.6		9.5		13.7		1.3		2.9		6.7

(*)The long-term debt of Southern Company Gas is recorded at amortized cost, including the fair value adjustments at the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043.