Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	7	$	—	$	—	$	7
Interest rate derivatives	—		22		—		—		22
Nuclear decommissioning trusts:(*)
Domestic equity	541		69		—		—		610
Foreign equity	47		160		—		—		207
U.S. Treasury and government agency securities	—		152		—		—		152
Municipal bonds	—		64		—		—		64
Corporate bonds	11		278		—		—		289
Mortgage and asset backed securities	—		145		—		—		145
Private equity	—		—		—		17		17
Other	16		9		—		—		25
Cash equivalents	790		—		—		—		790
Other investments	9		—		1		—		10
Total	$	1,414	$	906	$	1	$	17	$	2,338
Liabilities:
Energy-related derivatives	$	—	$	220	$	—	$	—	$	220
Interest rate derivatives	—		30		—		—		30
Total	$	—	$	250	$	—	$	—	$	250


(*)	Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases and the lending pool. See Note 1 under "Nuclear Decommissioning" for additional information.

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	13	$	—	$	—	$	13
Interest rate derivatives	—		8		—		—		8
Nuclear decommissioning trusts:(*)
Domestic equity	583		85		—		—		668
Foreign equity	34		184		—		—		218
U.S. Treasury and government agency securities	—		130		—		—		130
Municipal bonds	—		62		—		—		62
Corporate bonds	—		299		—		—		299
Mortgage and asset backed securities	—		139		—		—		139
Private equity	—		—		—		3		3
Other	11		13		—		—		24
Cash equivalents	397		—		—		—		397
Other investments	9		—		1		—		10
Total	$	1,034	$	933	$	1	$	3	$	1,971
Liabilities:
Energy-related derivatives	$	—	$	201	$	—	$	—	$	201
Interest rate derivatives	—		24		—		—		24
Total	$	—	$	225	$	—	$	—	$	225


(*)	Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases and the lending pool. See Note 1 under "Nuclear Decommissioning" for additional information.

Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments

As of December 31, 2015 and 2014, the fair value measurements of private equity investments held in the nuclear decommissioning trust that are calculated at net asset value per share (or its equivalent) as a practical expedient, as well as the nature and risks of those investments, were as follows:



	Fair Value		Unfunded Commitments		Redemption Frequency	Redemption Notice Period
	(in millions)
As of December 31, 2015	$	17	$	28	Not Applicable	Not Applicable
As of December 31, 2014	$	3	$	7	Not Applicable	Not Applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt, including securities due within one year:
2015	$	27,216	$	27,913
2014	$	23,814	$	25,816

Alabama Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	1	$	—	$	—	$	1
Nuclear decommissioning trusts:^(*)
Domestic equity	359		68		—		—		427
Foreign equity	47		47		—		—		94
U.S. Treasury and government agency securities	—		27		—		—		27
Corporate bonds	11		135		—		—		146
Mortgage and asset backed securities	—		18		—		—		18
Private equity	—		—		—		17		17
Other	—		5		—		—		5
Cash equivalents	68		—		—		—		68
Total	$	485	$	301	$	—	$	17	$	803
Liabilities:
Interest rate derivatives	$	—	$	15	$	—	$	—	$	15
Energy-related derivatives	—		55		—		—		55
Total	$	—	$	70	$	—	$	—	$	70


(*)	Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases. See Note 1 under "Nuclear Decommissioning" for additional information.

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs		Net Asset Value as a Practical Expedient
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		(NAV)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	1	$	—	$	—	$	1
Nuclear decommissioning trusts:^(*)
Domestic equity	403		83		—		—		486
Foreign equity	34		63		—		—		97
U.S. Treasury and government agency securities	—		34		—		—		34
Corporate bonds	—		111		—		—		111
Mortgage and asset backed securities	—		18		—		—		18
Private equity	—		—		—		3		3
Other	—		5		—		—		5
Cash equivalents	162		—		—		—		162
Total	$	599	$	315	$	—	$	3	$	917
Liabilities:
Interest rate derivatives	$	—	$	8	$	—	$	—	$	8
Energy-related derivatives	—		53		—		—		53
Total	$	—	$	61	$	—	$	—	$	61


(*)	Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases. See Note 1 under "Nuclear Decommissioning" for additional information.

Fair value measurements of investments calculated at net asset value per share as well as the nature and risk of those investments

As of December 31, 2015 and 2014, the fair value measurements of private equity investments held in the nuclear decommissioning trusts that are calculated at net asset value per share (or its equivalent) as a practical expedient, as well as the nature and risks of those investments, were as follows:



	Fair Value		Unfunded Commitments		Redemption Frequency	Redemption Notice Period
	(in millions)
As of December 31, 2015	$	17	$	28	Not Applicable	Not Applicable
As of December 31, 2014	$	3	$	7	Not Applicable	Not Applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt, including securities due within one year:
2015	$	6,849	$	7,192
2014	$	6,586	$	7,321

Georgia Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	2	$	—	$	2
Interest rate derivatives	—		5		—		5
Nuclear decommissioning trusts:(*)
Domestic equity	182		1		—		183
Foreign equity	—		113		—		113
U.S. Treasury and government agency securities	—		125		—		125
Municipal bonds	—		64		—		64
Corporate bonds	—		143		—		143
Mortgage and asset backed securities	—		127		—		127
Other	16		4		—		20
Cash equivalents	63		—		—		63
Total	$	261	$	584	$	—	$	845
Liabilities:
Energy-related derivatives	$	—	$	15	$	—	$	15
Interest rate derivatives	—		6		—		6
Total	$	—	$	21	$	—	$	21


(*)	Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases and the lending pool. See Note 1 under "Nuclear Decommissioning" for additional information.

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	7	$	—	$	7
Interest rate derivatives	—		6		—		6
Nuclear decommissioning trusts:(*)
Domestic equity	180		2		—		182
Foreign equity	—		121		—		121
U.S. Treasury and government agency securities	—		96		—		96
Municipal bonds	—		62		—		62
Corporate bonds	—		188		—		188
Mortgage and asset backed securities	—		121		—		121
Other	11		8		—		19
Total	$	191	$	611	$	—	$	802
Liabilities:
Energy-related derivatives	$	—	$	27	$	—	$	27
Interest rate derivatives	—		14		—		14
Total	$	—	$	41	$	—	$	41


(*)	Includes the investment securities pledged to creditors and collateral received, and excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases and the lending pool. See Note 1 under "Nuclear Decommissioning" for additional information.

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt, including securities due within one year:
2015	$	10,145	$	10,480
2014	$	9,673	$	10,552

Gulf Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Interest rate derivatives	$	—	$	1	$	—	$	1
Cash equivalents	18		—		—		18
Total	$	18	$	1	$	—	$	19
Liabilities:
Energy-related derivatives	$	—	$	100	$	—	$	100

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Cash equivalents	$	18	$	—	$	—	$	18
Liabilities:
Energy-related derivatives	$	—	$	72	$	—	$	72

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt:
2015	$	1,303	$	1,339
2014	$	1,362	$	1,477

Mississippi Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Cash equivalents	$	52	$	—	$	—	$	52
Liabilities:
Energy-related derivatives	$	—	$	47	$	—	$	47

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Cash equivalents	$	115	$	—	$	—	$	115
Liabilities:
Energy-related derivatives	$	—	$	45	$	—	$	45

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt:
2015	$	2,537	$	2,413
2014	$	2,320	$	2,382

Southern Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2015, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2015:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	4	$	—	$	4
Interest rate derivatives	—		3		—		3
Cash equivalents	511		—		—		511
Total	$	511	$	7	$	—	$	518
Liabilities:
Energy-related derivatives	$	—	$	3	$	—	$	3

As of December 31, 2014, 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
	Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
As of December 31, 2014:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	5	$	—	$	5
Cash equivalents	18		—		—		18
Total	$	18	$	5	$	—	$	23
Liabilities:
Energy-related derivatives	$	—	$	4	$	—	$	4

Financial instruments not having carrying amount equal to fair value

As of December 31, 2015 and 2014, other financial instruments for which the carrying amount did not equal fair value were as follows:



	Carrying Amount		Fair Value
	(in millions)
Long-term debt, including securities due within one year:
2015	$	3,122	$	3,117
2014	$	1,610	$	1,785