Derivatives - Balance Sheet Offsetting (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 43		$ 27
Derivative Liability, Fair Value, Gross Liability	43		56
Alabama Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	12		7
Derivative Liability, Fair Value, Gross Liability	6		8
Georgia Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	8		5
Derivative Liability, Fair Value, Gross Liability	16		21
Gulf Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	12		7
Derivative Liability, Fair Value, Gross Liability	13		17
Mississippi Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	8		5
Derivative Liability, Fair Value, Gross Liability	8		10
Southern Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		1
Derivative Liability, Fair Value, Gross Liability			1
Energy Related Derivative [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	7		2
Derivative Liability, Fair Value, Amount Offset Against Collateral	(10)		34
Energy Related Derivative [Member] | Alabama Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	6		2
Derivative Liability, Fair Value, Amount Offset Against Collateral	0		3
Energy Related Derivative [Member] | Georgia Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	0		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(8)		16
Energy Related Derivative [Member] | Gulf Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	4		1
Derivative Liability, Fair Value, Amount Offset Against Collateral	(5)		11
Energy Related Derivative [Member] | Mississippi Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	3		1
Derivative Liability, Fair Value, Amount Offset Against Collateral	(3)		6
Energy Related Derivative [Member] | Southern Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	0		1
Derivative Liability, Fair Value, Amount Offset Against Collateral	0		1
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	40	[1]	24	[2]
Derivative Liability, Fair Value, Gross Liability	(43)	[1]	56	[2]
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member] | Alabama Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	12	[1]	7	[2]
Derivative Liability, Fair Value, Gross Liability	(6)	[1]	8	[2]
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member] | Georgia Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	8	[1]	5	[2]
Derivative Liability, Fair Value, Gross Liability	(16)	[1]	21	[2]
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member] | Gulf Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	12	[1]	7	[2]
Derivative Liability, Fair Value, Gross Liability	(13)	[1]	17	[2]
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member] | Mississippi Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	8	[1]	5	[2]
Derivative Liability, Fair Value, Gross Liability	(8)	[1]	10	[2]
Energy Related Derivative [Member] | Net Amount Of Derivatives [Member] | Southern Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	[1]	1	[2]
Derivative Liability, Fair Value, Gross Liability	0	[1]	1	[2]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(33)	[3]	(22)	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	33	[3]	(22)	[4]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member] | Alabama Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(6)	[3]	(5)	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	6	[3]	(5)	[4]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member] | Georgia Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(8)	[3]	(5)	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	8	[3]	(5)	[4]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member] | Gulf Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(8)	[3]	(6)	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	8	[3]	(6)	[4]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member] | Mississippi Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	(5)	[3]	(4)	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	5	[3]	(4)	[4]
Energy Related Derivative [Member] | Gross Amount Of Derivatives [Member] | Southern Power [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0	[3]	0	[4]
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 0	[3]	$ 0	[4]

[1] None of the registrants offset fair value amounts for multiple derivative instruments executed with the same counterparty on the balance sheets; therefore, gross and net amounts of derivative assets and liabilities presented on the balance sheets are the same.

[2] (a) None of the registrants offset fair value amounts for multiple derivative instruments executed with the same counterparty on the balance sheets; therefore, gross and net amounts of derivative assets and liabilities presented on the balance sheets are the same.

[3] Includes gross amounts subject to netting terms that are not offset on the balance sheets and any cash/financial collateral pledged or received.Derivative Contracts at December 31, 2013 Fair Value SouthernCompany AlabamaPower GeorgiaPower GulfPower MississippiPower SouthernPower (in millions)Assets Energy-related derivatives: Energy-related derivatives presented in the Balance Sheet (a) $24 $7 $5 $7 $5 $1Gross amounts not offset in the Balance Sheet (b) (22) (5) (5) (6) (4) —Net energy-related derivative assets $2 $2 $— $1 $1 $1Liabilities Energy-related derivatives: Energy-related derivatives presented in the Balance Sheet (a) $56 $8 $21 $17 $10 $1Gross amounts not offset in the Balance Sheet (b) (22) (5) (5) (6) (4) —Net energy-related derivative liabilities $34 $3 $16 $11 $6 $1

[4] (b) Includes gross amounts subject to netting terms that are not offset on the balance sheets and any cash/financial collateral pledged or received.