Derivatives - Pre-tax Effect of Derivatives on Balance Sheets and Statements of Income (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	$ (55,000)	$ (109,000)
Regulatory Hedge Unrealized Gain	23,000	23,000
Other regulatory assets current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(26,000)	(74,000)
Other regulatory assets deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(29,000)	(35,000)
Other regulatory liabilities current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	16,000	10,000
Other regulatory liabilities deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	7,000	13,000
Alabama Power [Member] | Interest expense, net of amounts capitalized [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(3,000)	(3,000)	3,000
Alabama Power [Member] | Interest rate derivatives [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	(18,000)	(14,000)
Alabama Power [Member] | Other regulatory assets current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(3,000)	(14,000)
Alabama Power [Member] | Other regulatory assets deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(5,000)	(4,000)
Alabama Power [Member] | Other regulatory assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(8,000)	(18,000)
Alabama Power [Member] | Other Current Liabilities [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	5,000	2,000
Alabama Power [Member] | Other regulatory liabilities deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	2,000	3,000
Alabama Power [Member] | Other regulatory liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	7,000	5,000
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(13,000)	(30,000)
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(8,000)	(15,000)
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(21,000)	(45,000)
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	3,000	6,000
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other deferred credits and liabilities [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	2,000	5,000
Georgia Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	5,000	11,000
Gulf Power [Member] | Interest rate derivatives [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	0	0
Gulf Power [Member] | Interest rate derivatives [Member] | Interest expense, net of amounts capitalized [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(769)	(933)	(933)
Gulf Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(17,043)	(27,112)
Regulatory Hedge Unrealized Gain	6,962	4,358
Gulf Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(6,470)	(16,529)
Gulf Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(10,573)	(10,583)
Gulf Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	4,893	1,293
Gulf Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	2,069	3,065
Mississippi Power [Member] | Hedging Instruments for Regulatory Purposes [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(10,281)	(19,446)
Regulatory Hedge Unrealized Gain	4,803	2,519
Mississippi Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(3,652)	(13,116)
Mississippi Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory assets deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Loss	(6,629)	(6,330)
Mississippi Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities current [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	3,352	638
Mississippi Power [Member] | Hedging Instruments for Regulatory Purposes [Member] | Other regulatory liabilities deferred [Member] | Energy Related Derivative [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Regulatory Hedge Unrealized Gain	1,451	1,881
Mississippi Power [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	(774)	(14,364)
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(1,375)	(1,073)	48
Mississippi Power [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Energy Related Derivative [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	0	(3)
Mississippi Power [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Energy Related Derivative [Member] | Fuel [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	0	0	0
Mississippi Power [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest rate derivatives [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	(774)	(14,361)
Mississippi Power [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest rate derivatives [Member] | Interest expense, net of amounts capitalized [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(1,375)	(1,073)	48
Southern Power [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	(200)	100
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(6,100)	(10,100)	(12,000)
Southern Power [Member] | Energy Related Derivative [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	(200)	100
Southern Power [Member] | Energy Related Derivative [Member] | Depreciation and amortization [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	400	400	400
Southern Power [Member] | Interest rate derivatives [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	0	0	0
Southern Power [Member] | Interest rate derivatives [Member] | Interest expense, net of amounts capitalized [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	(6,500)	(10,500)	(11,400)
Southern Power [Member] | Interest rate derivatives [Member] | Other income (expense), net [Member]
Pre-tax effect of derivatives designated as cash flow hedging instruments
Gain (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)	$ 0	$ 0	$ (1,000)