Contingencies and Regulatory Matters (Details) (USD $)	3 Months Ended					3 Months Ended		12 Months Ended					3 Months Ended	12 Months Ended	3 Months Ended		1 Months Ended		3 Months Ended		12 Months Ended						0 Months Ended	12 Months Ended	3 Months Ended		12 Months Ended	3 Months Ended		12 Months Ended			3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Alabama Power [Member]	Mar. 31, 2013 Alabama Power [Member]	Dec. 31, 2013 Alabama Power [Member]	Mar. 31, 2014 Georgia Power [Member]	Mar. 31, 2013 Georgia Power [Member]	Dec. 31, 2013 Georgia Power [Member]	Jan. 02, 2014 Georgia Power [Member]	Jan. 02, 2013 Georgia Power [Member]	Jan. 02, 2012 Georgia Power [Member]	Jan. 02, 2011 Georgia Power [Member]	Mar. 31, 2014 Georgia Power [Member] Minimum [Member]	Dec. 31, 2013 Georgia Power [Member] Maximum [Member]	Mar. 31, 2014 Gulf Power [Member] clause	Mar. 31, 2013 Gulf Power [Member]	Mar. 31, 2013 Mississippi Power [Member]	Mar. 31, 2012 Mississippi Power [Member]	Mar. 31, 2014 Mississippi Power [Member]	Mar. 31, 2013 Mississippi Power [Member]	Dec. 31, 2013 Mississippi Power [Member]	Jan. 02, 2014 Mississippi Power [Member]	Dec. 31, 2012 Mississippi Power [Member]	Dec. 31, 2010 Mississippi Power [Member]	Jan. 31, 2013 Mississippi Power [Member] Maximum [Member]	Mar. 31, 2014 Gulf Power and Mississippi Power [Member]	Feb. 26, 2013 Electricity Generation Plant, Non-Nuclear [Member] Mississippi Power [Member]	Dec. 31, 2012 Electricity Generation Plant, Non-Nuclear [Member] Mississippi Power [Member]	Mar. 31, 2014 Kemper IGCC [Member]	Mar. 31, 2013 Kemper IGCC [Member]	Dec. 31, 2013 Kemper IGCC [Member]	Mar. 31, 2014 Kemper IGCC [Member] Mississippi Power [Member]		Dec. 31, 2013 Kemper IGCC [Member] Mississippi Power [Member]	Dec. 31, 2012 Kemper IGCC [Member] Mississippi Power [Member]	Mar. 31, 2013 Kemper IGCC [Member] Mississippi Power [Member] MW	Mar. 31, 2014 Kemper IGCC [Member] Mississippi Power [Member] Minimum [Member]	Mar. 31, 2014 Kemper IGCC [Member] Mississippi Power [Member] Maximum [Member]	Dec. 31, 2010 Mine [Member] Mississippi Power [Member]	Mar. 31, 2014 Other deferred charges and assets [Member] Georgia Power [Member]	Dec. 31, 2013 Current Liabilities And Other Deferred Credits And Liabilities [Member] Georgia Power [Member]	Mar. 31, 2014 Storm Reserve [Member] Georgia Power [Member]	Dec. 31, 2013 Storm Reserve [Member] Georgia Power [Member]	May 06, 2014 Subsequent Event [Member] Mississippi Power [Member]	Apr. 01, 2014 Subsequent Event [Member] Mississippi Power [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss																			$ 1,560,000,000
Environmental Matters
Civil penalties under Clean Air Act, per day, per violation, minimum	25,000
Civil penalties under Clean Air Act, per day, per violation, maximum	37,500
Environmental remediation liability						18,000,000									50,000,000
Civil penalties per day violation rate						37,500
Number of times of punitive damages in comparison to cost incurred by Environmental Protection Agency						3
Damages awarded			17,000,000			27,000,000
Amount have been recognized in the financial statements for the second claim						0
Increase in base rate under cost based electric tariff due to settlement																			10,100,000
Revenue to be received from increase in base rate																			6,900,000
Retail Regulatory Matters
Under recovered rate CNP balance			23,000,000		18,000,000
Under recovered rate CNP environmental balance			13,000,000		7,000,000
Over Recovered Fuel Cost																					14,500,000
Under recovered regulatory clause revenues																			1,800,000
Accumulated reserve balance for future storms			91,000,000		96,000,000
Over recovered fuel cost balance																																								157,000,000	58,000,000
Regulatory Assets																																										110,000,000	37,000,000
PSC Retail Rate Increase																																												3,600,000
Percentage Of PSC Retail Rate Increase																																												0.38%
Proportionate share owed in consortium agreement						45.70%
Increase In NCCR Tariff									60,000,000	50,000,000	35,000,000	223,000,000
Amortization to earnings of financing costs capitalized over the five year period						91,000,000
Amortization to earnings of financing costs capitalized, amortization term						5 years
Costs included in CWIP						32,000,000													2,670,000,000
Increase (decrease) in projected certified construction capital costs						5.00%
Estimated In-service Capital Cost													4,400,000,000	4,800,000,000
Cost incurred by Mississippi Power associated with plant including regulatory filing costs								2,000,000,000
Construction Capital Costs								400,000,000
Reduction in projected in-service cost due to recovered cost						425,000,000
Reduction In Depreciation Expense															62,500,000
Reduction In Depreciation Expense Year One															6,200,000
Psc Approved Annual Property Damage Reserve Accrual																																													3,300,000
Ownership percentage in scrubber project															50.00%				50.00%
Estimated cost of scrubber project																			330,000,000							660,000,000
Scrubber project expenditures amount																			188,100,000							370,200,000
Allowance For Funds Used During Construction Cost																			10,700,000
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost																												2,400,000,000				3,520,000,000	[1]		2,880,000,000
Period Rate Plan For Cost Accrued Through Additional Prudence Review																			7 years
Revisions To Revenue Requirement																			45,000,000
Alternate Financing																											1,000,000,000
Revenue Requirement Obligations																																					120,000,000	150,000,000
Costs associated with CCP12 grant funds																							245,300,000
Maximum Cap Construction Cost																																4,320,000,000	[1],[2]
Pre-tax charge to income																													380,000,000	540,000,000	1,180,000,000	380,000,000		1,180,000,000
After tax charge to income																													234,700,000	333,500,000	728,700,000	234,700,000		728,700,000
Costs Due To Extension Of In-service Date																			25,000,000
Costs included in CWIP						32,000,000													2,670,000,000
Cost deferred in other regulatory assets																			83,900,000
Other deferred charges and assets																			3,900,000
Previously expensed																			1,100,000
Settlement Agreement To Increase Rates																									172,000,000
Prudence Review Of Plant Cost Within Settlement Agreement																			6 months
Amortization Period For Construction Project																			40 years
Increase Retail Rates In Year One																	15.00%
Increase Retail Rates In Year Two																			3.00%
Settlement Agreement Collection Amount To Mitigate Rate Impact Year Two																			156,000,000
Regulatory Liabilities																			135,500,000
Retail Revenues	3,858,000,000	3,298,000,000	1,297,000,000	1,141,000,000		2,050,000,000	1,729,000,000								303,120,000	259,877,000			207,038,000	168,310,000												4,400,000
Reduced percentage interest transferred under asset purchase agreement																			15.00%
Term of Management Fee Contract																																							40 years
Percentage of Carbon Dioxide Captured from Project																			70.00%
Percentage of Contract to Purchase Carbon Dioxide from Project																			30.00%
Purchase of Interest																					17.50%			17.50%
Deposit received																						75,000,000	150,000,000
Maximum period of discretion in the event senior unsecured credit rating falls																		15 days
Internal Revenue Code Section Forty Eight Tax Credits Phase I																			133,000,000
Internal Revenue Code Section Forty Eight Tax Credits Phase I I																			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%
Tax Credit Carryforward, Amount																			276,400,000
Additional Bonus Depreciation For Property Acquired Future Periods																			50.00%
Positive Impact From Bonus Depreciation																																170,000,000
Electric Generating Units, Capacity																																				75
Capacity Revenues Under Power Supply Agreement																					$ 17,500,000
Number Of Regulatory Clauses															4

[1] The 2012 MPSC CPCN Order approved a construction cost cap of up to $2.88 billion, net of the DOE Grants and excluding the Cost Cap Exceptions.

[2] Amounts in the Current Estimate reflect costs through May 31, 2015, but do not reflect any adjustments as a result of the expected placement of the combined cycle and the associated common facilities portion of the Kemper IGCC in service in the summer of 2014.