Contingencies and Regulatory Matters (Details) (USD $)	6 Months Ended		6 Months Ended			0 Months Ended			6 Months Ended													1 Months Ended		6 Months Ended	12 Months Ended							0 Months Ended		6 Months Ended						0 Months Ended												6 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Kivalina Case [Member]	Jun. 30, 2013 Alabama Power [Member] Coal_Fired_Generating_Facilities claim	Dec. 31, 2012 Alabama Power [Member]	May 14, 2013 Georgia Power [Member] Purchased_Power_Agreement	Apr. 30, 2013 Georgia Power [Member] Purchased_Power_Agreement	Apr. 22, 2013 Georgia Power [Member] Purchased_Power_Agreement Property MW	Jun. 30, 2013 Georgia Power [Member] Purchased_Power_Agreement Property Coal_Fired_Generating_Facilities MW	Jun. 28, 2013 Georgia Power [Member]	May 13, 2013 Georgia Power [Member] MW	Apr. 29, 2013 Georgia Power [Member] MW	Jan. 02, 2013 Georgia Power [Member]	Dec. 31, 2012 Georgia Power [Member]	Jan. 02, 2012 Georgia Power [Member]	Jan. 02, 2011 Georgia Power [Member]	Jun. 30, 2013 Georgia Power [Member] Minimum [Member]	Jun. 30, 2013 Georgia Power [Member] Maximum [Member]	Jun. 30, 2013 Gulf Power [Member]	Dec. 31, 2012 Gulf Power [Member]	Jul. 12, 2013 Gulf Power [Member] Subsequent Event [Member]	Mar. 31, 2012 Mississippi Power [Member]	May 31, 2010 Mississippi Power [Member] MW	Jun. 30, 2013 Mississippi Power [Member] mi	Dec. 31, 2012 Mississippi Power [Member]	Mar. 27, 2013 Mississippi Power [Member]	Mar. 15, 2013 Mississippi Power [Member]	Mar. 05, 2013 Mississippi Power [Member]	Feb. 01, 2013 Mississippi Power [Member]	Jan. 18, 2013 Mississippi Power [Member]	Dec. 31, 2010 Mississippi Power [Member]	Jul. 30, 2013 Mississippi Power [Member] Subsequent Event [Member]	Jul. 11, 2013 Mississippi Power [Member] Subsequent Event [Member] Customer	Jun. 30, 2013 Mississippi Power [Member] Minimum [Member]	Jun. 30, 2013 Mississippi Power [Member] Maximum [Member]	Jun. 30, 2013 Mississippi Power [Member] MRA Revenue [Member]	Dec. 31, 2012 Mississippi Power [Member] MRA Revenue [Member]	Jun. 30, 2013 Mississippi Power [Member] MB Revenue [Member]	Dec. 31, 2012 Mississippi Power [Member] MB Revenue [Member]	Jul. 30, 2013 Mississippi Power [Member] Cost Cap Exceptions [Member]	Jul. 29, 2013 Mississippi Power [Member] Cost Cap Exceptions [Member]	Jun. 30, 2013 Gulf Power and Mississippi Power [Member]	Apr. 17, 2013 Plant Bowen [Member] Georgia Power [Member] MW	Jul. 11, 2013 Plant Boulevard [Member] Georgia Power [Member] Subsequent Event [Member] MW	Jul. 11, 2013 Plant Branch [Member] Georgia Power [Member] Subsequent Event [Member] MW	Jul. 11, 2013 Plant Yates [Member] Georgia Power [Member] Subsequent Event [Member] MW	Jul. 11, 2013 Plant McManus [Member] Georgia Power [Member] Subsequent Event [Member] MW	Jul. 11, 2013 Plant Kraft [Member] Georgia Power [Member] Subsequent Event [Member] MW	Jun. 30, 2013 Utility Scale Projects [Member] Georgia Power [Member] MW	Jun. 30, 2013 Electric Distribution [Member] Georgia Power [Member] MW	Jul. 12, 2013 Electric Transmission [Member] Gulf Power [Member] Subsequent Event [Member]	Jun. 30, 2013 Electricity Generation Plant, Non-Nuclear [Member] Mississippi Power [Member]	Apr. 04, 2013 Plant Bowen Unit One [Member] Georgia Power [Member] MW	Jun. 30, 2013 Kemper IGCC [Member]	Jun. 30, 2013 Kemper IGCC [Member]	Dec. 31, 2012 Kemper IGCC [Member]	Jun. 30, 2013 Kemper IGCC [Member] Mississippi Power [Member]	Mar. 31, 2013 Kemper IGCC [Member] Mississippi Power [Member]	Jun. 30, 2013 Kemper IGCC [Member] Mississippi Power [Member]	Dec. 31, 2012 Kemper IGCC [Member] Mississippi Power [Member]	Apr. 04, 2013 Plant Bowen Unit Two [Member] Georgia Power [Member] MW	Jun. 30, 2013 Regulatory Clause Revenues, under-recovered [Member] Alabama Power [Member]	Jun. 30, 2013 Deferred Under Recovered Regulatory Clause Revenue [Member] Alabama Power [Member]	Jun. 30, 2013 Current Liabilities [Member]	Jun. 30, 2013 Current Liabilities [Member] Georgia Power [Member]	Dec. 31, 2012 Current Liabilities And Other Deferred Credits And Liabilities [Member]	Dec. 31, 2012 Current Liabilities And Other Deferred Credits And Liabilities [Member] Georgia Power [Member]
Environmental Matters
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
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
Damages from lost property values and relocating village cost, lower range			95,000,000
Damages from lost property values and relocating village cost, upper range			400,000,000
Environmental remediation liability									18,000,000										51,000,000
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 annual base wholesale revenues																								22,600,000
Increase in base rate under cost based electric tariff due to settlement																								24,200,000
Revenue to be received from increase in base rate									334,000,000															18,000,000
Estimated Increase In ECCR Tariff									132,000,000
Estimated Increase In Demand Side Management Tariffs									5,000,000
Estimated Increase In Municipal Franchise Fee Tariff									11,000,000
Period For Levelized Revenue Requirements									3 years
Retail Regulatory Matters
Under recovered rate CNP balance				9,000,000	9,000,000
Under recovered rate CNP environmental balance				21,000,000	21,000,000
Under recovered certified power purchase agreements																																																														8,000,000	13,000,000
Over recovered fuel costs				13,000,000																17,100,000
Under recovered regulatory clause revenues					4,000,000														16,400,000
Fuel Vendor Payment																			26,600,000
Accumulated reserve balance for future storms				95,000,000	103,000,000
Over recovered fuel cost balance																																																																108,000,000	108,000,000	230,000,000	230,000,000
PSC Retail Rate Increase										482,000,000											74,400,000					7,100,000																									16,400,000
Percentage Of PSC Retail Rate Increase										6.10%																0.90%
Retail Rate Of Return On Common Equity										11.50%							10.25%	12.25%	11.50%
Capacity Of Units Approved For Decertification Of Units																																											32	28	1,016	579	122	316
Period Extension Of The MATS Rule									1 year
Energy From Solar Generation									525																																								425	100
Number of wind PPAs								2	4
Number of wind farms								2
Energy from wind-powered generating facilities								250
Number Of Biomass PPAs						2	2
Capacity of small power production facility											56	50
Number Of Biomass Facilities									2
Additional contractual obligations in 2015									13,000,000
Additional contractual obligations in 2016									47,000,000
Additional contractual obligations in 2017									49,000,000
Additional contractual obligations thereafter									1,290,000,000
Proportionate share owed in consortium agreement									45.70%
Increase In NCCR Tariff													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									46,000,000															2,240,000,000
Construction and capital costs included in semi-annual construction monitoring report									2,000,000,000					200,000,000
Increase (decrease) in projected certified construction capital costs									5.00%
Estimated In-service Capital Cost									4,800,000,000
Cost incurred by Mississippi Power associated with plant including regulatory filing costs									2,000,000,000
Reduction in projected in-service cost due to recovered cost									425,000,000
Over recovered purchased power capacity costs																			1,400,000
Under recovered purchased power capacity costs																				800,000
Under recovered environmental cost																			11,500,000	1,900,000
Under recovered energy conservation costs																			5,100,000	800,000
Required Customers For Energy Efficiency Programs																																	25,000
Required Period For Filing Quick Start Plans																								6 months
Period For Quick Start Plans To Be In Effect																																		2 years	3 years
Annual PEP Filing Rate Increase																												1.925%		1.99%
Annual PEP Filing Rate Increase Amount																												15,300,000		15,800,000
Potential additional revenues in 2013 as a result of late implementation of the 2013 PEP rate increase																								3,300,000
Annual PEP lookback refund to customers																											4,700,000
Psc Approved Annual Property Damage Reserve Accrual																													3,200,000
Ownership percentage in scrubber project																			50.00%					50.00%
Estimated cost of scrubber project																								330,000,000																		660,000,000
Scrubber project expenditures amount																								116,400,000																		232,900,000
Annual adjustment in retail fuel cost recovery factor, percentage decrease																														4.70%
Annual adjustment in retail fuel cost recovery factor, amount																														35,500,000
Amount of over recovered retail fuel costs included in balance sheets																								38,000,000	56,600,000
Amount of over recovered fuel costs																																				11,900,000	19,000,000	900,000	2,100,000
Amount of under recovered emissions allowance costs																								1,400,000	400,000
Storm reserve balance																								58,500,000
Integrated Coal Gasification Combined Cycle [Abstract]
Plant Capacity Under Coal Gasification Combined Cycle Technology																							582
Co Two Pipeline Infrastructure																								61
Estimated Cost																																																				2,400,000,000							2,880,000,000
Cost Of Plant																																																											3,290,000,000
Costs associated with CCP12 grant funds																								245,000,000
Maximum Cap Construction Cost																																3,870,000,000																											2,740,000,000
Estimated Cost of Pipeline Infrastructure																								86,100,000																	115,000,000
Cost Of Lignite Mine																								210,200,000																	245,000,000
AFUDC Cost																								193,800,000																324,000,000
General Exceptions																								55,200,000																101,000,000
Pre-tax charge to income																																																						450,000,000	990,000,000	540,000,000	450,000,000	462,000,000		78,000,000
After tax charge to income	16,000,000																																																					277,900,000	611,300,000	333,500,000	277,900,000	285,300,000		48,200,000
Costs included in CWIP									46,000,000															2,240,000,000
Cost deferred in other regulatory assets																								49,700,000
Other deferred charges and assets	3,800,000																							3,900,000
Previously expensed																								1,000,000
Settlement Agreement To Increase Rates																																			172,000,000
Collaboration Period To File Settlement Agreement																								3 months
Beginning Period Of Operation Of Plant																								7 years
Period Of Time For Decision On Rate Recovery Plan Within Filing																								4 months
Prudence Review Of Plant Cost Within Settlement Agreement																								6 months
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
Settlement Agreement Collection Amount To Mitigate Rate Impact Year One																												126,000,000
Regulatory Liabilities	27,000,000																							27,000,000
Other Regulatory Liabilities, Current	66,000,000	107,000,000		16,000,000	3,000,000				35,000,000					73,000,000					6,666,000	25,887,000				9,101,000	5,376,000																													3,000,000	3,000,000		3,000,000		3,000,000
Other regulatory liabilities, deferred	320,000,000	289,000,000		192,000,000	183,000,000														47,356,000	47,863,000				79,995,000	56,984,000																													24,000,000	24,000,000		24,000,000		24,000,000
Reduced percentage interest transferred under asset purchase agreement																									15.00%
Purchase of Interest																									17.50%						17.50%
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
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																								$ 412,000,000
Carry Forward For Unused Tax Credits																								20 years
Additional Bonus Depreciation For Property Acquired Future Periods																								50.00%
Electric Generating Units, Capacity																																																					700								700
Earnings Above ROE Range To Share With Customers									66.70%
Earnings Above ROE Range To Retain									33.30%
Required Period For Filing Comprehensive Portfolio Plans																								1 year