Contingencies and Regulatory Matters (Details) (USD $)	3 Months Ended	6 Months Ended	12 Months Ended			6 Months Ended	1 Months Ended	6 Months Ended		1 Months Ended		6 Months Ended			6 Months Ended						6 Months Ended	12 Months Ended	13 Months Ended													6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012 Entity	Dec. 31, 2009	Jun. 14, 2012	Dec. 31, 2011	Jun. 30, 2012 Kivalina Case [Member]	Jul. 31, 2007 Alabama Power [Member]	Jun. 30, 2012 Alabama Power [Member] Coal_Fired_Generating_Facilities Claims	Dec. 31, 2011 Alabama Power [Member]	Apr. 30, 2012 Georgia Power [Member]	Jul. 31, 2007 Georgia Power [Member]	Jun. 30, 2012 Georgia Power [Member] MW Coal_Fired_Generating_Facilities Claims	Jun. 01, 2012 Georgia Power [Member]	Dec. 31, 2011 Georgia Power [Member]	Jun. 30, 2012 Gulf Power [Member]	Jun. 19, 2012 Gulf Power [Member]	Mar. 12, 2012 Gulf Power [Member]	Dec. 31, 2011 Gulf Power [Member]	Mar. 12, 2012 Gulf Power [Member] Minimum [Member]	Mar. 12, 2012 Gulf Power [Member] Maximum [Member]	Jun. 30, 2012 Mississippi Power [Member]	Dec. 31, 2009 Mississippi Power [Member]	Apr. 30, 2012 Mississippi Power [Member]	Jul. 09, 2012 Mississippi Power [Member]	Feb. 14, 2012 Mississippi Power [Member]	Feb. 02, 2012 Mississippi Power [Member]	Dec. 31, 2011 Mississippi Power [Member]	May 26, 2010 Mississippi Power [Member]	Jun. 14, 2012 Mississippi Power [Member] Minimum [Member]	Jun. 14, 2012 Mississippi Power [Member] Maximum [Member]	Jun. 30, 2012 Mississippi Power [Member] MRA Revenue [Member]	Dec. 31, 2011 Mississippi Power [Member] MRA Revenue [Member]	Jun. 30, 2012 Mississippi Power [Member] MB Revenue [Member]	Dec. 31, 2011 Mississippi Power [Member] MB Revenue [Member]	Jun. 30, 2012 Gulf Power and Mississippi Power [Member]	Jun. 30, 2012 Electricity Generation Plant, Non-Nuclear [Member] Mississippi Power [Member]	Jun. 30, 2012 Mine [Member] Mississippi Power [Member]	Jun. 30, 2012 Kemper IGCC [Member] Mississippi Power [Member]
Contingencies and Regulatory Matters (Textual) [Abstract]
Number of coal fired generating facilities at which new source review violations occurred								5				3
Number of dismissed claims against Subsidiary								5
Total Number of Claims								8
Claims left for summary disposition or trial against Alabama Power								3
Environmental remediation liability												$ 20,000,000			$ 60,000,000
Damages from lost property values and relocating village cost, lower range						95,000,000
Civil penalties per violation rate												37,500
Number of times of punitive damages in comparison to cost incurred by Environmental Protection Agency												3
Other deferred credits and liabilities	16,144,000,000	16,144,000,000			15,383,000,000			5,440,000,000	5,326,000,000			6,943,000,000		6,703,000,000	1,145,059,000			1,021,743,000			1,014,603,000						776,781,000
Claims awarded to companies related to nuclear fuel disposal litigation							17,000,000				30,000,000
Damages awarded										27,000,000
Amount have been recognized in the financial statements for the second claim												0
Under recovered rate CNP balance								2,000,000	6,000,000
Under recovered rate CNP Environmental balance								26,000,000	11,000,000
Accumulated reserve balance for future storms								105,000,000
Increase in base rate under cost based electric tariff due to settlement																					22,600,000
Revised rate period																					12 months
Revenue to be received from increase in base rate																					17,000,000
Percentage of increase in annual revenue																									0.30%
Percentage of decrease in annual revenue after revised notice																									0.16%
Interim rates under bond subject to refund																								55,300,000
Revenue request to recover financing costs for stipulated rate increase																													55,300,000	58,600,000
Amount approved for property damage reserve																										3,700,000
Amount of over recovered retail fuel costs included in the balance sheets																					55,500,000						42,400,000
Percentage of decrease in fuel rates													19.00%			7.80%
Decrease in annual billings for fuel costs													567,000,000			58,800,000
Amount of over recovered fuel costs																															17,400,000	14,300,000	2,400,000	2,200,000
Amount of over recovered MRA emissions allowance cost included in the balance sheets																					1,000,000						1,700,000
Deferred cost related to construction																					5,000,000
Grant funds receivable during construction																					245,300,000
Portion of deferred construction cost under review																					46,000,000
Reduction in projected in-service cost due to recovered cost												4,400,000,000
Under recovered energy conservation costs															1,600,000			3,100,000
Electric generating capacity in Mega Watts under contractor												1,100
Recovery of project financing cost as per Legislation												1,700,000,000
Total certified cost												6,100,000,000
Over recovered fuel cost balance												99,000,000
Under recovered regulatory clause revenues	20,000,000	20,000,000			143,000,000			16,000,000						137,000,000	4,070,000			5,530,000
Over recovered purchased power capacity costs															7,900,000			8,000,000
Over recovered environmental cost.															3,600,000			10,000,000
Amount of government construction cost incentive received																												296,000,000
Maximum cap construction cost																					2,880,000,000
Cost incurred for use of mine																					99,900,000
Term of management fee contract with liberty fuels company																																					40 years
Tax credits (Phase I)																						133,000,000
Tax credit (Phase II)																							279,000,000
Minimum percentage of carbon dioxide that must be capture and sequester to remain eligible for the phase II tax credits																					65.00%
Received or accrued tax benefits related to Tax credit																					197,000,000
Percentage interest acquired under asset purchase agreement																					17.50%
Percentage interest transferred under asset purchase agreement																					17.50%
Reduced Percentage interest transferred under asset purchase agreement																					15.00%
Deposit received																					150,000,000
Maximum period to refund deposit upon termination of asset purchase agreement																					60 days
Maximum period of discretion in the event senior unsecured credit rating falls																					15 days
Estimated cost																																				2,400,000,000		2,880,000,000
Estimated cost less cost cap																																						72,000,000
Percentage of financing costs of construction work in progress																												100.00%
Cost deferred in other regulatory assets	3,484,000,000	3,484,000,000			3,532,000,000			1,001,000,000	994,000,000			1,550,000,000		1,604,000,000	332,325,000			323,116,000			195,721,000						185,694,000
Other deferred charges and assets	455,000,000	455,000,000			481,000,000			144,000,000	186,000,000			221,000,000		187,000,000	27,567,000			39,493,000			37,640,000						28,674,000
Capacity of units include application request by Georgia Power that country PSC certify purchase from four PPAs selected through 2015 request for proposal process												998
Retail rate of return on common equity																			9.25%	11.25%
Estimated cost of scrubber project																					330,000,000														660,000,000
Ownership percentage in Scrubber project															50.00%						50.00%
Scrubber project expenditures amount																					41,000,000														82,000,000
Cost deferred in other regulatory assets																					29,000,000
Previously expensed																					1,000,000
Amortization to earnings of financing costs capitalized over the five year period												91,000,000
Costs included in CWIP												64,000,000									1,600,000,000
Contractor's estimated adjustment to contract price												425,000,000
Damages from lost property values and relocating village cost, upper range						400,000,000
Increase in retail rates and charges																	64,000,000
Previously approved interim retail rate increase																	38,500,000
Average retail rate of return on common equity															10.25%
Increase in retail rates and charges in next fiscal year															4,000,000
Over Recovered Fuel Cost															41,600,000			9,900,000
Estimated capital cost of mine																					245,000,000
Cost incurred by Mississippi Power associated with plant including regulatory filing costs																					1,700,000,000
Costs associated with CCP12 grant funds																					245,300,000
Other deferred charges and assets																					2,600,000
Contingencies and Regulatory Matters (Additional Textual) [Abstract]
MC Asset Recovery insurance settlement	19,000,000	19,000,000	(202,000,000)
Amount of insurance claim received in respect of litigation settlement				25,000,000
Legal fee related to insurance recoveries				6,000,000
Net amount received of insurance claim in respect of litigation settlement				19,000,000
Civil penalties under Clean Air Act per day, lower range		25,000
Civil penalties under Clean Air Act per day, upper range		37,500
Number of entities received notice from TCEQ requesting their participation in anticipated site redemption		100
Damages from lost property values and relocating village cost, lower range						$ 95,000,000