Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2012

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	26	$	—	$	26
Interest rate derivatives	—		10		—		10
Nuclear decommissioning trusts:(a)
Domestic equity	453		65		—		518
Foreign equity	28		172		—		200
U.S. Treasury and government agency securities	—		134		—		134
Municipal bonds	—		55		—		55
Corporate bonds	—		234		—		234
Mortgage and asset backed securities	—		141		—		141
Other investments	—		20		—		20
Cash equivalents	384		—		—		384
Other investments	9		—		15		24
Total	$	874	$	857	$	15	$	1,746
Liabilities:
Energy-related derivatives	$	—	$	111	$	—	$	111

(a) 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, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	14	$	—	$	14
Interest rate derivatives	—		13		—		13
Foreign currency derivatives	—		2		—		2
Nuclear decommissioning trusts:(a)
Domestic equity	396		58		—		454
Foreign equity	124		48		—		172
U.S. Treasury and government agency securities	17		33		—		50
Municipal bonds	—		82		—		82
Corporate bonds	—		260		—		260
Mortgage and asset backed securities	—		151		—		151
Other investments	—		36		—		36
Cash equivalents and restricted cash	1,024		—		—		1,024
Other investments	3		50		14		67
Total	$	1,564	$	747	$	14	$	2,325
Liabilities:
Energy-related derivatives	$	—	$	245	$	—	$	245
Interest rate derivatives	—		33		—		33
Foreign currency derivatives	—		3		—		3
Total	$	—	$	281	$	—	$	281

(a) 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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value		Unfunded Commitments	Redemption Frequency	Redemption  Notice Period
As of December 31, 2012:	(in millions)
Nuclear decommissioning trusts:
Foreign equity funds	$	117	None	Monthly	5 days
Corporate bonds – commingled funds	9		None	Daily	Not applicable
Equity – commingled funds	55		None	Daily/Monthly	Daily/7 days
Other – commingled funds	10		None	Daily	Not applicable
Trust-owned life insurance	96		None	Daily	15 days
Cash equivalents:
Money market funds	384		None	Daily	Not applicable
As of December 31, 2011:
Nuclear decommissioning trusts:
Corporate bonds – commingled funds	$	32	None	Daily	Not applicable
Equity – commingled funds	48		None	Daily/Monthly	Daily/7 days
Other – commingled funds	25		None	Daily	Not applicable
Trust-owned life insurance	87		None	Daily	15 days
Cash equivalents and restricted cash:
Money market funds	1,024		None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, 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:
2012	$	21,530	$	23,480
2011	$	20,272	$	22,144

Southern Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	2.1	$	—	$	2.1
Cash equivalents	26.0		—		—		26.0
Total	$	26.0	$	2.1	$	—	$	28.1
Liabilities:
Energy-related derivatives	$	—	$	1.3	$	—	$	1.3

As of December 31, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	0.6	$	—	$	0.6
Cash equivalents	14.2		—		—		14.2
Total	$	14.2	$	0.6	$	—	$	14.8
Liabilities:
Energy-related derivatives	$	—	$	9.8	$	—	$	9.8

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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value		Unfunded Commitments	Redemption Frequency	Redemption   Notice Period
As of December 31, 2012:	(in millions)
Cash equivalents:
Money market funds	$	26.0	None	Daily	Not applicable
As of December 31, 2011:
Cash equivalents:
Money market funds	$	14.2	None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, 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:
2012	$	1,306	$	1,444
2011	$	1,303	$	1,397

Mississippi Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in thousands)
Assets:
Energy-related derivatives	$	—	$	2,519	$	—	$	2,519
Foreign currency derivatives	—		—		—		—
Cash equivalents	125,600		—		—		125,600
Total	$	125,600	$	2,519	$	—	$	128,119
Liabilities:
Energy-related derivatives	$	—	$	19,446	$	—	$	19,446
Interest rate derivatives	—		—		—		—
Foreign currency derivatives	—		37		—		37
Total	$	—	$	19,483	$	—	$	19,483

As of December 31, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in thousands)
Assets:
Energy-related derivatives	$	—	$	162	$	—	$	162
Foreign currency derivatives	—		1,526		—		1,526
Cash equivalents	133,900		—		—		133,900
Total	$	133,900	$	1,688	$	—	$	135,588
Liabilities:
Energy-related derivatives	$	—	$	51,152	$	—	$	51,152
Interest rate derivatives	—		15,208		—		15,208
Foreign currency derivatives	—		2,510		—		2,510
Total	$	—	$	68,870	$	—	$	68,870

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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value		Unfunded Commitments	Redemption Frequency	Redemption Notice Period
As of December 31, 2012	(in  thousands)
Cash equivalents:
Money market funds	$	125,600	None	Daily	Not applicable
As of December 31, 2011
Cash equivalents:
Money market funds	$	133,900	None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, other financial instruments for which the carrying amount did not equal fair value were as follows:

	Carrying Amount		Fair Value
	(in thousands)
Long-term debt:
2012	$	1,840,933	$	1,956,799
2011	$	1,343,596	$	1,426,808

Gulf Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in thousands)
Assets:
Energy-related derivatives	$	—	$	4,358	$	—	$	4,358
Cash equivalents	15,231		—		—		15,231
Total	$	15,231	$	4,358	$	—	$	19,589
Liabilities:
Energy-related derivatives	$	—	$	27,112	$	—	$	27,112

As of December 31, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in thousands)
Assets:
Energy-related derivatives	$	—	$	198	$	—	$	198
Cash equivalents	13,949		—		—		13,949
Total	$	13,949	$	198	$	—	$	14,147
Liabilities:
Energy-related derivatives	$	—	$	40,983	$	—	$	40,983

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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value	Unfunded Commitments	Redemption Frequency	Redemption     Notice Period
As of December 31, 2012:	(in thousands)
Cash equivalents:
Money market funds	$15,231	None	Daily	Not applicable
As of December 31, 2011:
Cash equivalents:
Money market funds	$13,949	None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, other financial instruments for which the carrying amount did not equal fair value were as follows:

	Carrying Amount		Fair Value
	(in thousands)
Long-term debt:
2012	$	1,245,870	$	1,367,404
2011	$	1,235,447	$	1,350,237

Georgia Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	11	$	—	$	11
Nuclear decommissioning trusts:(a)
Domestic equity	162		1		—		163
Foreign equity	—		117		—		117
U.S. Treasury and government agency securities	—		105		—		105
Municipal bonds	—		55		—		55
Corporate bonds	—		133		—		133
Mortgage and asset backed securities	—		115		—		115
Other investments	—		10		—		10
Cash equivalents	15		—		—		15
Total	$	177	$	547	$	—	$	724
Liabilities:
Energy-related derivatives	$	—	$	45	$	—	$	45

(a) 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, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	13	$	—	$	13
Nuclear decommissioning trusts:(a)
Domestic equity	143		1		—		144
Foreign equity	100		—		—		100
U.S. Treasury and government agency securities	—		25		—		25
Municipal bonds	—		82		—		82
Corporate bonds	—		167		—		167
Mortgage and asset backed securities	—		123		—		123
Other investments	—		25		—		25
Cash equivalents	13		—		—		13
Total	$	256	$	436	$	—	$	692
Liabilities:
Energy-related derivatives	$	—	$	95	$	—	$	95

(a) 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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value		Unfunded Commitments	Redemption Frequency	Redemption Notice Period
As of December 31, 2012:	(in millions)
Nuclear decommissioning trusts:
Foreign equity fund	$	117	None	Monthly	5 days
Corporate bonds — commingled funds	9		None	Daily	Not applicable
Other — commingled funds	10		None	Daily	Not applicable
Cash equivalents:
Money market funds	15		None	Daily	Not applicable
As of December 31, 2011:
Nuclear decommissioning trusts:
Corporate bonds — commingled funds	$	32	None	Daily	Not applicable
Other — commingled funds	25		None	Daily	Not applicable
Cash equivalents:
Money market funds	13		None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, 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:
2012	$	9,624	$	10,427
2011	$	8,418	$	9,209

Alabama Power [Member]

Fair Value Disclosures [Line Items]

Assets and liabilities measured at fair value on a recurring basis

As of December 31, 2012, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2012:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Energy-related derivatives	$	—	$	5	$	—	$	5
Nuclear decommissioning trusts:(a)
Domestic equity	291		64		—		355
Foreign equity	28		55		—		83
U.S. Treasury and government agency securities	—		29		—		29
Corporate bonds	—		101		—		101
Mortgage and asset backed securities	—		26		—		26
Other investments	—		10		—		10
Total	$	319	$	290	$	—	$	609
Liabilities:
Energy-related derivatives	$	—	$	18	$	—	$	18

(a) Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases.

As of December 31, 2011, assets and liabilities measured at fair value on a recurring basis during the period, together with the level of the fair value hierarchy in which they fall, 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, 2011:	(Level 1)		(Level 2)		(Level 3)		Total
	(in millions)
Assets:
Nuclear decommissioning trusts:(a)
Domestic equity	$	253	$	57	$	—	$	310
Foreign equity	24		48		—		72
U.S. Treasury and government agency securities	17		8		—		25
Corporate bonds	—		93		—		93
Mortgage and asset backed securities	—		28		—		28
Other investments	—		11		—		11
Cash equivalents and restricted cash	209		—		—		209
Total	$	503	$	245	$	—	$	748
Liabilities:
Energy-related derivatives	$	—	$	48	$	—	$	48
Interest rate derivatives	—		18		—		18
Total	$	—	$	66	$	—	$	66

(a) Excludes receivables related to investment income, pending investment sales, and payables related to pending investment purchases.

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, 2012 and 2011, the fair value measurements of investments calculated at net asset value per share (or its equivalent), as well as the nature and risks of those investments, were as follows:

	Fair Value	Unfunded Commitments	Redemption Frequency	Redemption Notice Period
As of December 31, 2012:	(in millions)
Nuclear decommissioning trusts:
Equity-commingled funds	$55	None	Daily/Monthly	Daily/7 days
Trust-owned life insurance	96	None	Daily	15 days
As of December 31, 2011:
Nuclear decommissioning trusts:
Equity-commingled funds	$48	None	Daily/Monthly	Daily/7 days
Trust-owned life insurance	87	None	Daily	15 days
Cash equivalents and restricted cash:
Money market funds	209	None	Daily	Not applicable

Financial instruments not having carrying amount equal to fair value

As of December 31, 2012 and 2011, 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:
2012	$6,179	$6,899
2011	$6,132	$6,874