Contingencies and Regulatory Matters - Textual (Details) (USD $)	12 Months Ended			3 Months Ended									12 Months Ended		24 Months Ended		0 Months Ended		1 Months Ended	2 Months Ended		84 Months Ended	0 Months Ended	1 Months Ended				6 Months Ended		12 Months Ended		18 Months Ended	0 Months Ended				1 Months Ended				3 Months Ended	27 Months Ended
	Dec. 31, 2014		Dec. 31, 2010	Dec. 31, 2014		Sep. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013		Dec. 31, 2014		Dec. 12, 2014	Dec. 01, 2014	Aug. 31, 2013 Provisions	Dec. 31, 2014 MW		Dec. 31, 2004	Jan. 01, 2014	Dec. 31, 2013		Jul. 31, 2013 MW	Jul. 31, 2007	Dec. 31, 2014		Dec. 31, 2012	Dec. 31, 2008 MW	Jun. 30, 2014	Jan. 29, 2015	Aug. 01, 2014	Apr. 01, 2013	Mar. 19, 2013	May 20, 2014	Mar. 31, 2013	Jan. 31, 2013	Feb. 28, 2013	Dec. 31, 2012	Dec. 31, 2014		Dec. 10, 2013	Jun. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 MW	Dec. 09, 2014	Aug. 05, 2014	Jan. 01, 2013	Jun. 01, 2012	Jan. 01, 2012	Jan. 01, 2011	Jan. 01, 2015	Jul. 01, 2014 MW	Oct. 31, 2014	Oct. 20, 2014	Oct. 09, 2014	May 06, 2014	Jan. 31, 2014	Jan. 04, 2014	May 31, 2013	Feb. 01, 2015	Oct. 22, 2014
Loss Contingencies [Line Items]
Gain (Loss) Related to Litigation Settlement			$ (202,000,000)
Environmental Matters [Abstract]
Civil penalties under Clean Air Act per day, lower range	25,000
Civil penalties under Clean Air Act per day, upper range	37,500
Retail Regulatory Matters [Abstract]
Other Regulatory Assets Current	346,000,000			346,000,000				207,000,000					207,000,000		346,000,000					346,000,000				207,000,000				346,000,000														346,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation	2,201,000,000			2,201,000,000				2,018,000,000					2,018,000,000		2,201,000,000					2,201,000,000				2,018,000,000				2,201,000,000		1,757,000,000											1,757,000,000	2,201,000,000
Net Regulatory Assets	(4,664,000,000)			(4,664,000,000)				(2,624,000,000)					(2,624,000,000)		(4,664,000,000)					(4,664,000,000)				(2,624,000,000)				(4,664,000,000)														(4,664,000,000)
Unrecognized Tax Benefits	170,000,000			170,000,000				7,000,000					7,000,000		170,000,000					170,000,000				7,000,000				170,000,000		70,000,000											70,000,000	170,000,000				120,000,000
Accrued tax benefits on tax credits	379,000,000			379,000,000											379,000,000					379,000,000								379,000,000														379,000,000
Other Cost of Removal Obligations	1,215,000,000			1,215,000,000				1,275,000,000					1,275,000,000		1,215,000,000					1,215,000,000				1,275,000,000				1,215,000,000														1,215,000,000
Amount of Insurance Claim Received in Respect of Litigation Settlement																																												15,000,000	25,000,000
Legal Fee Related to Insurance Recoveries								4,000,000					4,000,000											4,000,000						6,000,000											6,000,000
Net Amount Received of Insurance Claim in Respect of Litigation Settlement								11,000,000					11,000,000											11,000,000						19,000,000											19,000,000
Other Regulatory Assets Deferred	4,334,000,000			4,334,000,000				2,495,000,000					2,495,000,000		4,334,000,000					4,334,000,000				2,495,000,000				4,334,000,000														4,334,000,000
Kemper IGCC [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Pre-Tax Charge To Income	868,000,000			70,000,000		418,000,000	380,000,000	40,000,000		150,000,000	450,000,000	540,000,000	1,200,000,000		2,050,000,000
After Tax Charge To Income	536,000,000			43,200,000		258,100,000	234,700,000	24,700,000		92,600,000	277,900,000	333,500,000	729,000,000		1,260,000,000
Unrecognized Tax Benefits	160,000,000			160,000,000											160,000,000					160,000,000								160,000,000														160,000,000
Gulf Power and Mississippi Power [Member]
Retail Regulatory Matters [Abstract]
Percent ownership	50.00%			50.00%											50.00%					50.00%								50.00%														50.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost of Project One	660,000,000			660,000,000											660,000,000					660,000,000								660,000,000														660,000,000
Alabama Power [Member]
Loss Contingencies [Line Items]
Percent Of Designated Customer Value Benchmark Survey										33.30%
Environmental Matters [Abstract]
Civil penalties under Clean Air Act per day, lower range	25,000
Civil penalties under Clean Air Act per day, upper range	37,500
Nuclear Fuel Disposal Costs [Abstract]
Claims awarded to companies related to nuclear fuel disposal litigation																	26,000,000					17,000,000
Retail Regulatory Matters [Abstract]
Rate Adjustment Period	2 years
Maximum percentage of Rate RSE	4.00%
Maximum annual percentage of ratio rate	5.00%
Minimum projected retail return on common equity at which retail rates remain unchanged	13.00%
Maximum projected retail return on common equity at which retail rates remain unchanged	14.50%
Maximum increase in rate RSE	5.00%																	4.51%
Rate RSE Increase																		3.49%
Rate RSE Increase Amount																		181,000,000
Allowed Equity Ratio																			45.00%
Number Of Provisions																			2
Adjusting Point Of Weighted Cost Of Equity																			5.98%
Percent Of Basis Points																		0.07%	0.07%
Under recovered certified PPA balance	56,000,000			56,000,000											56,000,000					56,000,000								56,000,000														56,000,000
Approved And Certified Energy From Wind-Powered Generating Facilities								200					200											200						200											200						200
Number Of Wind Farms													2
Under Recovered Rate Cnp Balance																			75,000,000
Under recovered environmental clause	49,000,000			49,000,000											49,000,000					49,000,000								49,000,000														49,000,000
Period Which Deferred Regulatory Asset Account, Amortized	3 years
Estimate Amortization Of Regulatory Asset																				28,000,000
Amortization of Regulatory Asset																				123,000,000
Regulatory Liability Amortization																				120,000,000
Approved billing rate under rate ECR up to (cents per KWH)	0.05910
Future stated rates under rate Ecr factor in terms of per units	0.02681
Over recovered fuel cost	47,000,000			47,000,000				42,000,000					42,000,000		47,000,000					47,000,000				42,000,000				47,000,000														47,000,000
Deferred over recovered regulatory clause revenues	47,000,000			47,000,000				15,000,000					15,000,000		47,000,000					47,000,000				15,000,000				47,000,000														47,000,000
Maximum Period for recovery deferred storm-related operations and maintenance costs and any future reserve deficit	24 months
Maximum total rate NDR charge per month, non-residential customer account	10			10											10					10								10														10
Maximum total rate NDR charge per month, residential customer account	5			5											5					5								5														5
Old Natural Disaster Reserve Authorized Limit	75,000,000			75,000,000											75,000,000					75,000,000								75,000,000														75,000,000
Period To Amortize Expense																			3 years
Energy From Wind-Powered Generating Facilities								400					400											400
Percentage Under Recovered Rate CNP Balance																			1.50%
Other Regulatory Assets Current	84,000,000			84,000,000				54,000,000					54,000,000		84,000,000					84,000,000				54,000,000				84,000,000														84,000,000
Percent ownership	14.00%			14.00%											14.00%					14.00%								14.00%														14.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation	829,000,000			829,000,000				730,000,000					730,000,000		829,000,000					829,000,000				730,000,000				829,000,000		589,000,000											589,000,000	829,000,000
Net Regulatory Assets	(738,000,000)			(738,000,000)				(92,000,000)					(92,000,000)		(738,000,000)					(738,000,000)				(92,000,000)				(738,000,000)														(738,000,000)
Unrecognized Tax Benefits								0					0											0						31,000,000											31,000,000					32,000,000
Electric Generating Units, Capacity	1,000			1,000											1,000					1,000								1,000														1,000
Other Cost of Removal Obligations	744,000,000			744,000,000				828,000,000					828,000,000		744,000,000					744,000,000				828,000,000				744,000,000														744,000,000
Non-nuclear Outage Costs	95,000,000
Compliance And Pension Costs	28,000,000
Other Regulatory Assets Deferred	1,063,000,000			1,063,000,000				645,000,000					645,000,000		1,063,000,000					1,063,000,000				645,000,000				1,063,000,000														1,063,000,000
Alabama Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity																			5.75%
Alabama Power [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity																			6.21%
Alabama Power [Member] | Fuel Recovery Clause [Member]
Retail Regulatory Matters [Abstract]
Deferred over recovered regulatory clause revenues	47,000,000			47,000,000											47,000,000					47,000,000								47,000,000														47,000,000
Alabama Power [Member] | Non-Environmental Federal Mandates [Member]
Retail Regulatory Matters [Abstract]
Deferral of maintenance costs																																																50,000,000
Alabama Power [Member] | Current Rate Stabilization And Equalization [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity																			5.85%
Alabama Power [Member] | Current Rate Stabilization And Equalization [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity																			6.53%
Adjusting Point Of Weighted Cost Of Equity																			6.19%
Alabama Power [Member] | Plant Gorgas Units 6 and 7 [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units	200
Alabama Power [Member] | Plant Greene County Units 1 And 2 [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units	300
Alabama Power [Member] | Plant Gorgas [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Electric Generating Units, Capacity	12,200			12,200											12,200					12,200								12,200														12,200
Alabama Power [Member] | Plant Barry Units 1 And 2 [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units	250
Alabama Power [Member] | Plant Barry Unit 3 [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units	225
Alabama Power [Member] | Plant Farley [Member]
Retail Regulatory Matters [Abstract]
Recovery Amount From Customers Associated With Permanent Disposal Of Nuclear Waste	8,000,000			8,000,000											8,000,000					8,000,000								8,000,000														8,000,000							14,000,000
Georgia Power [Member]
Loss Contingencies [Line Items]
Increase In NCCR Tariff																							60,000,000																											50,000,000		35,000,000	223,000,000
Number of Plants For Decertification																										16
Environmental Matters [Abstract]
Civil penalties under Clean Air Act per day, lower range	25,000
Civil penalties under Clean Air Act per day, upper range	37,500
Environmental remediation liability	22,000,000			22,000,000											22,000,000					22,000,000								22,000,000														22,000,000
Nuclear Fuel Disposal Costs [Abstract]
Claims awarded to companies related to nuclear fuel disposal litigation																	18,000,000					27,000,000					27,000,000
Retail Regulatory Matters [Abstract]
Portion of Actual Earnings Above Approved ROE Band Retained by Subsidiary Company	33.33333%
Portion of Actual Earnings Above Approved ROE Band Refunded to Customers	66.66667%
Regulatory Liability Amortization	31,000,000												14,000,000																	31,000,000
Retail Rate of Return on Common Equity																							10.95%
Test Period For PSC																							90 days
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units																										2,093
Period for Environmental Construction	9 years																						9 years
Other Regulatory Assets Current	136,000,000			136,000,000				106,000,000					106,000,000		136,000,000					136,000,000				106,000,000				136,000,000														136,000,000
Estimated In-service Capital Cost	4,400,000,000
Amendment To Estimated In-service Capital Cost	4,800,000,000
Revenue Subject To Refund	13,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation	1,255,000,000			1,255,000,000				1,222,000,000					1,222,000,000		1,255,000,000					1,255,000,000				1,222,000,000				1,255,000,000		1,105,000,000											1,105,000,000	1,255,000,000
Net Regulatory Assets	(2,529,000,000)			(2,529,000,000)				(1,886,000,000)					(1,886,000,000)		(2,529,000,000)					(2,529,000,000)				(1,886,000,000)				(2,529,000,000)														(2,529,000,000)
Unrecognized Tax Benefits								0					0											0						23,000,000											23,000,000					47,000,000
Other Cost of Removal Obligations	46,000,000			46,000,000				43,000,000					43,000,000		46,000,000					46,000,000				43,000,000				46,000,000														46,000,000
Extension Period For Mercury And Air Toxics Standards																										1 year
Civil Penalties Per Violation Rate	37,500			37,500											37,500					37,500								37,500														37,500
Number of Times of Punitive Damages in Comparison to Cost Incurred by Environmental Protection Agency	3			3											3					3								3														3
Number Of Intervenors Approved ARP																								11
Number of Intervenors																								13
Increase in Tariff Rate One																							80,000,000
Estimated Increase In ECCR Tariff																							25,000,000
Estimated Demand Side Management Tariffs																							1,000,000
Estimated Increase In Municipal Franchise Fee Tariff																							4,000,000
Base Revenue Under Alternative Rate Plan																							110,000,000
Approved Increase in Annual Billing Based on Fuel Cost Recovery Rate																																																		122,000,000	567,000,000
Adjustment To FuelCost Recovery Rate If Under Recovered Fuel Balance Exceeds Budget Thereafter	200,000,000
Required Period For Options And Hedges	24 months
Over Recovered Fuel Balance	199,000,000			199,000,000				58,000,000					58,000,000		199,000,000					199,000,000				58,000,000				199,000,000														199,000,000
Accrual Under Alternate Rate Plan	30,000,000
Other Regulatory Assets Deferred	1,753,000,000			1,753,000,000				1,113,000,000					1,113,000,000		1,753,000,000					1,753,000,000				1,113,000,000				1,753,000,000														1,753,000,000
Electric Generating Capacity in Mega Watts Under Consortium Agreement																															1,100
Additional Construction Capital Costs																												200,000,000				2,800,000,000
Percentage of Proportionate Share Owed in Consortium Agreement	45.70%
Estimated Adjustment to Contract Price Related to Issues that May Impact Project Budget and Schedule	425,000,000
Increase (Decrease) In Projected Certified Construction Capital Costs	5.00%
Georgia Power [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Increase In NCCR Tariff																																																						27,000,000
Revenue to be Received from Increase in Base Rate Two																																																						136,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Increase In Municipal Franchise Fee Tariff																																																						3,000,000
Increase in Tariff Rate Two																																																						107,000,000
Estimated Increase In ECCR Tariff One																																																						23,000,000
Estimated Increase In Demand Side Management Tariffs																																																						3,000,000
Delay Of Estimated In-service Date																																	18 months
Georgia Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Retail Rate of Return on Common Equity																							10.00%
Georgia Power [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Retail Rate of Return on Common Equity																							12.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Additional Construction Capital Costs	114,000,000
Damages In Connection With Counterclaim	113,000,000
Georgia Power [Member] | Property Damage Reserves Liability [Member]
Retail Regulatory Matters [Abstract]
Deferral of maintenance costs	98,000,000			98,000,000				37,000,000					37,000,000		98,000,000					98,000,000				37,000,000				98,000,000														98,000,000
Other Regulatory Assets Current	30,000,000			30,000,000				30,000,000					30,000,000		30,000,000					30,000,000				30,000,000				30,000,000														30,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Other Regulatory Assets Deferred	68,000,000			68,000,000				7,000,000					7,000,000		68,000,000					68,000,000				7,000,000				68,000,000														68,000,000
Georgia Power [Member] | Storm Costs [Member]
Retail Regulatory Matters [Abstract]
Deferral of maintenance costs	98,000,000			98,000,000				37,000,000					37,000,000		98,000,000					98,000,000				37,000,000				98,000,000														98,000,000
Georgia Power [Member] | Plant Vogtle Units 3 And 4 [Member]
Retail Regulatory Matters [Abstract]
Estimated In-service Capital Cost	5,000,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Monthly Operational Readiness Costs	10,000,000
Monthly Financing Costs	30,000,000
Construction Financing Costs	2,500,000,000
Georgia Power [Member] | Plant Branch Units Three And Four [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										1,016
Georgia Power [Member] | Plant Yates [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										579
Georgia Power [Member] | Plant McManus [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										122
Georgia Power [Member] | Plant Branch Unit One [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										250
Georgia Power [Member] | Plant Kraft [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										316
Georgia Power [Member] | Plant Branch Unit Two [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units																										319
Georgia Power [Member] | Plant Mitchell [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Small Power Production Facility																																																							155
Mississippi Power [Member]
Environmental Matters [Abstract]
Civil penalties under Clean Air Act per day, lower range	25,000
Civil penalties under Clean Air Act per day, upper range	37,500
Cost of Services, Environmental Remediation	500,000
FERC Matters [Abstract]
Increase in Annual Base Wholesale Revenues																														22,600,000											22,600,000
Period Over Which Annual Revenue Will Increase Under Tariff																														12 months
Increase in Base Rate Under Cost Based Electric Tariff Due to Settlement																																			24,200,000		10,100,000
Retail Regulatory Matters [Abstract]
Anticipates of elimination adjustment will result in additional revenues													3,300,000
Annual PEP Lookback Refund To Customers																																																														4,700,000
Over recovered fuel cost								14,500,000					14,500,000											14,500,000
Other Regulatory Assets Current	72,840,000			72,840,000				48,583,000					48,583,000		72,840,000					72,840,000				48,583,000				72,840,000														72,840,000
Costs included in CWIP	3,040,000,000			3,040,000,000											3,040,000,000					3,040,000,000								3,040,000,000														3,040,000,000
Required Customers For Energy Efficiency Programs																										25,000
Required Period For Filing Quick Start Plans																										6 months
Percentage Of PSC Retail Rate Increase																																																											0.38%
Project expenditures, cumulative	518,200,000			518,200,000											518,200,000					518,200,000								518,200,000														518,200,000
Project expenditures, cumulative, proportionate share	263,400,000			263,400,000											263,400,000					263,400,000								263,400,000														263,400,000
AFUDC Cost	19,200,000
PSC Retail Rate Increase																																																									6,700,000		3,600,000
Integrated Coal Gasification Combined Cycle [Abstract]
Plant capacity under coal gasification combined cycle technology in Mega Watts	582
New Co2 Pipeline Infrastructure	61			61											61					61								61														61
Costs Related to Grant Funding																														245,300,000											245,300,000
Maximum cap construction cost																																							2,880,000,000
Retail Rate Recovery															257,200,000
Acquisition Period For SMEPA	180 days
Costs included in CWIP	3,040,000,000			3,040,000,000											3,040,000,000					3,040,000,000								3,040,000,000														3,040,000,000
Loss Contingency, Estimate of Possible Loss	2,050,000,000			2,050,000,000											2,050,000,000					2,050,000,000								2,050,000,000														2,050,000,000
Other Property And Investments	1,800,000			1,800,000											1,800,000					1,800,000								1,800,000														1,800,000
Prepaid Supplies	32,500,000			32,500,000											32,500,000					32,500,000								32,500,000														32,500,000
Cost deferred in other regulatory assets	147,700,000			147,700,000											147,700,000					147,700,000								147,700,000														147,700,000
Other deferred charges and assets	11,600,000			11,600,000											11,600,000					11,600,000								11,600,000														11,600,000
Asset Retirement Obligation	48,248,000			48,248,000				41,910,000					41,910,000		48,248,000					48,248,000				41,910,000				48,248,000		42,115,000											42,115,000	48,248,000
Previously expensed	1,100,000			1,100,000											1,100,000					1,100,000								1,100,000														1,100,000
Lignite Mining Costs	44,700,000			44,700,000											44,700,000					44,700,000								44,700,000														44,700,000
Increase Retail Rates In Year One																																				15.00%		15.00%
Increase Retail Rates In Year Two																							3.00%
Settlement Agreement Collection Amount To Mitigate Rate Impact Year Two																							156,000,000
Net Regulatory Assets	(171,764,000)			(171,764,000)				(66,604,000)					(66,604,000)		(171,764,000)					(171,764,000)				(66,604,000)				(171,764,000)														(171,764,000)
Regulatory Liabilities Collected	257,200,000
Unrecognized Tax Benefits	164,821,000			164,821,000				3,840,000					3,840,000		164,821,000					164,821,000				3,840,000				164,821,000		5,755,000											5,755,000	164,821,000				4,964,000
Reduced Percentage Interest Transferred under Asset Purchase Agreement																														15.00%
Capacity Revenues Under Power Supply Agreement													16,700,000
Term of management fee contract	40 years
Percentage of Carbon dioxide captured from project by purchase Denbury	70.00%			70.00%											70.00%					70.00%								70.00%														70.00%
Percentage of contract to purchase carbon dioxide from Kemper IGCC	30.00%			30.00%											30.00%					30.00%								30.00%														30.00%
Purchase of interest in plant																														17.50%											17.50%
Deposit Received																														150,000,000											150,000,000															50,000,000		50,000,000		75,000,000	75,000,000
Maximum Period to Refund Deposit upon Termination of Asset Purchase Agreement	15 days
Tax credits (Phase II)	279,000,000
Accrued tax benefits on tax credits	276,400,000			276,400,000											276,400,000					276,400,000								276,400,000														276,400,000
Tax Credit Carryforward Utilized	210,000,000			210,000,000											210,000,000					210,000,000								210,000,000														210,000,000
Minimum percentage of carbon dioxide that must be capture and sequester to remain eligible for the phase II tax credits	65.00%
Prudence Review Of Plant Cost Within Settlement Agreement																																		3 years
Amortization Period For Construction Project	40 years
Annual PEP Filing Rate Increase												1.90%																										1.90%
Annual PEP Filing Rate Increase Amount												15,300,000																										15,300,000
Estimated Cost of Project, Proportionate Share	330,000,000			330,000,000											330,000,000					330,000,000								330,000,000														330,000,000
Debt Instrument, Interest Rate, Stated Percentage	10.134%			10.134%				9.932%					9.932%		10.134%					10.134%				9.932%				10.134%		9.967%											9.967%	10.134%				7.13%
Other Cost of Removal Obligations	165,999,000			165,999,000				156,683,000					156,683,000		165,999,000					165,999,000				156,683,000				165,999,000														165,999,000
Bonus Depreciation for Property Acquired																																							50.00%
Grant For Energy Efficiency And Renewable Program																																		15,000,000
Period Of Grant For Energy Efficiency and Renewable Program																																		15 years
Conservation Fund																																		2,000,000
Other Regulatory Assets Deferred	385,410,000			385,410,000				200,620,000					200,620,000		385,410,000					385,410,000				200,620,000				385,410,000														385,410,000
Mississippi Power [Member] | Subsequent Event [Member]
Retail Regulatory Matters [Abstract]
Proposed Change in Annual Revenues																																																						1,100,000									100,000
Mississippi Power [Member] | Plant Daniel Units 1 and 2 [Member]
Retail Regulatory Matters [Abstract]
Percent ownership	50.00%			50.00%											50.00%					50.00%								50.00%														50.00%
Mississippi Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Period For Quick Start Plans To Be In Effect																										2 years
Mississippi Power [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Period For Quick Start Plans To Be In Effect																										3 years
Mississippi Power [Member] | Retail [Member]
Retail Regulatory Matters [Abstract]
Proposed Change in Annual Revenues	7,900,000			7,900,000											7,900,000					7,900,000								7,900,000														7,900,000
Under Recovered Fuel Cost	2,500,000			2,500,000											2,500,000					2,500,000								2,500,000														2,500,000
Mississippi Power [Member] | MRA Revenue [Member]
Retail Regulatory Matters [Abstract]
Over recovered fuel cost								7,300,000					7,300,000											7,300,000
Amount Of Over Recovered Emissions Allowance Cost	300,000			300,000											300,000					300,000								300,000														300,000
Amount Of Under Recovered Emissions Allowance Cost								3,800,000					3,800,000											3,800,000
Mississippi Power [Member] | MB Revenue [Member]
Retail Regulatory Matters [Abstract]
Over recovered fuel cost	200,000			200,000				300,000					300,000		200,000					200,000				300,000				200,000														200,000
Mississippi Power [Member] | Gulf Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost of Project One	660,000,000			660,000,000											660,000,000					660,000,000								660,000,000														660,000,000
Mississippi Power [Member] | Gulf Power [Member] | Plant Daniel Units 1 and 2 [Member]
Retail Regulatory Matters [Abstract]
Percent ownership	50.00%			50.00%											50.00%					50.00%								50.00%														50.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Electric Generating Units, Capacity	1,000			1,000											1,000					1,000								1,000														1,000
Mississippi Power [Member] | Mirror Construction Work In Progress [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Net Regulatory Assets	270,779,000	[1]		270,779,000	[1]			90,524,000	[1]				90,524,000	[1]	270,779,000	[1]				270,779,000	[1]			90,524,000	[1]			270,779,000	[1]													270,779,000	[1]
Mississippi Power [Member] | Electricity Generation Plant, Non-Nuclear [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost																																							2,400,000,000
Alternate Financing																																								1,000,000,000
Mississippi Power [Member] | Kemper IGCC [Member]
Retail Regulatory Matters [Abstract]
Deferral of maintenance costs	147,700,000			147,700,000											147,700,000					147,700,000								147,700,000														147,700,000
Projected Balance Of Regulatory Assets	269,800,000			269,800,000											269,800,000					269,800,000								269,800,000														269,800,000
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost	4,230,000,000	[2]
Maximum cap construction cost	5,200,000,000	[3],[4]
Monthly Charge Of Allowance For Equity Funds Used During Construction	13,000,000
Monthly Cost Regulatory Assets Deferred	7,000,000
Asset Retirement Obligation	23,600,000			23,600,000											23,600,000					23,600,000								23,600,000														23,600,000
Pre-Tax Charge To Income				70,000,000		418,000,000	380,000,000	40,000,000		150,000,000	450,000,000	462,000,000	1,100,000,000																	78,000,000											78,000,000	2,050,000,000
After Tax Charge To Income				43,200,000		258,100,000	234,700,000	24,700,000		92,600,000	277,900,000	285,300,000	680,500,000																	48,200,000											48,200,000	1,260,000,000
Electric Generating Units, Capacity												75																										75
Positive Impact From Bonus Depreciation																							130,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Estimated In-service Capital Cost	25,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Minimum [Member] | Subsequent Event [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Positive Impact From Bonus Depreciation																																																						45,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Estimated In-service Capital Cost	30,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Maximum [Member] | Subsequent Event [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Positive Impact From Bonus Depreciation																																																						50,000,000
Mississippi Power [Member] | Mine [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Term of management fee contract			40 years
Mississippi Power [Member] | Plant Sweatt Units 1 And 2 [Member]
Retail Regulatory Matters [Abstract]
Capacity Unit Conversion To Non-fossil Fuel Source																																		80
Mississippi Power [Member] | Plant Watson Units 4 And 5 [Member]
Retail Regulatory Matters [Abstract]
Capacity Unit Conversion To Non-fossil Fuel Source																																		750
Mississippi Power [Member] | Plant Greene County Units 1 And 2 [Member]
Retail Regulatory Matters [Abstract]
Costs included in CWIP	5,600,000			5,600,000											5,600,000					5,600,000								5,600,000														5,600,000
Capacity Unit Conversion To Non-fossil Fuel Source																																		200
Integrated Coal Gasification Combined Cycle [Abstract]
Costs included in CWIP	5,600,000			5,600,000											5,600,000					5,600,000								5,600,000														5,600,000
Mississippi Power [Member] | Plant Watson [Member]
Retail Regulatory Matters [Abstract]
Costs included in CWIP	2,000,000			2,000,000											2,000,000					2,000,000								2,000,000														2,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Costs included in CWIP	2,000,000			2,000,000											2,000,000					2,000,000								2,000,000														2,000,000
Gulf Power [Member]
Environmental Matters [Abstract]
Civil penalties under Clean Air Act per day, lower range	25,000
Civil penalties under Clean Air Act per day, upper range	37,500
Environmental remediation liability	48,300,000			48,300,000											48,300,000					48,300,000								48,300,000														48,300,000
Retail Regulatory Matters [Abstract]
Period Of Treasury Yield Rate	30 years
Percent Of Basis Points	0.25%			0.25%											0.25%					0.25%								0.25%														0.25%
Retail Rate of Return on Common Equity								10.25%					10.25%											10.25%
Other Regulatory Assets Current	74,242,000			74,242,000				18,536,000					18,536,000		74,242,000					74,242,000				18,536,000				74,242,000														74,242,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation	16,711,000			16,711,000				16,184,000					16,184,000		16,711,000					16,711,000				16,184,000				16,711,000		16,055,000											16,055,000	16,711,000
Net Regulatory Assets	(319,644,000)			(319,644,000)				(160,224,000)					(160,224,000)		(319,644,000)					(319,644,000)				(160,224,000)				(319,644,000)														(319,644,000)
Unrecognized Tax Benefits	46,000			46,000				45,000					45,000		46,000					46,000				45,000				46,000		5,007,000											5,007,000	46,000				2,892,000
Estimated Cost of Project One	330,000,000			330,000,000											330,000,000					330,000,000								330,000,000														330,000,000
Base Revenue In Year One								35,000,000					35,000,000											35,000,000
Base Revenue In Year Two								20,000,000					20,000,000											20,000,000
Period of Treasury Rate Above Basis Points	6 months
Other Cost of Removal Obligations	234,587,000			234,587,000				228,148,000					228,148,000		234,587,000					234,587,000				228,148,000				234,587,000														234,587,000
Reduction In Depreciation Expense	8,400,000
Retail Rate Increase (Decrease)																																																																41,200,000
Projected fuel cost over or under recovery threshold, as a percentage of projected fuel revenue	10.00%
Purchased Power Over (Under) Recovered Balance Percentage	10.00%
Period of Establishment of Conservation Goals, in Years	5 years
Period Numeric Conservation Goals Cover, in Years	10 years
Other Regulatory Assets Deferred	416,028,000			416,028,000				340,415,000					340,415,000		416,028,000					416,028,000				340,415,000				416,028,000														416,028,000
Gulf Power [Member] | Plant Daniel Units 1 and 2 [Member]
Retail Regulatory Matters [Abstract]
Percent ownership	50.00%			50.00%											50.00%					50.00%								50.00%														50.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Electric Generating Units, Capacity	1,000			1,000											1,000					1,000								1,000														1,000
Gulf Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Percent Of Basis Points	0.75%			0.75%											0.75%					0.75%								0.75%														0.75%
Retail Rate of Return on Common Equity								9.25%					9.25%											9.25%
Integrated Coal Gasification Combined Cycle [Abstract]
Projected fuel cost over or under recovery threshold, as a percentage of projected fuel revenue	10.00%
Gulf Power [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Retail Rate of Return on Common Equity								11.25%					11.25%											11.25%
Under Recovered Regulatory Clause Revenues and Other Current Liabilities [Member] | Gulf Power [Member]
Environmental Matters [Abstract]
Environmental remediation liability	4,500,000			4,500,000											4,500,000					4,500,000								4,500,000														4,500,000
Other Regulatory Assets, Deferred and Other Deferred Credits and Liabilities [Member] | Gulf Power [Member]
Environmental Matters [Abstract]
Environmental remediation liability	43,700,000			43,700,000											43,700,000					43,700,000								43,700,000														43,700,000
Other regulatory liabilities current [Member] | Gulf Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered fuel balance								21,000,000					21,000,000											21,000,000
Regulatory Clause Revenues, under-recovered [Member] | Gulf Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered fuel balance	39,900,000			39,900,000											39,900,000					39,900,000								39,900,000														39,900,000
Integrated Coal Gasification Combined Cycle [Abstract]
Purchased Power, Over Under Recovered Balance	300,000			300,000				2,800,000					2,800,000		300,000					300,000				2,800,000				300,000														300,000
Under Recovered Environmental Cost	9,800,000			9,800,000				14,400,000					14,400,000		9,800,000					9,800,000				14,400,000				9,800,000														9,800,000
Under Recovered Energy Conservation Costs	2,600,000			2,600,000											2,600,000					2,600,000								2,600,000														2,600,000
Over Recovered Energy Conservation Costs								7,000,000					7,000,000											7,000,000
Under Recovered Regulatory Clause Revenues [Member] | Alabama Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered certified PPA balance	27,000,000			27,000,000											27,000,000					27,000,000								27,000,000														27,000,000
Under recovered environmental clause	47,000,000			47,000,000											47,000,000					47,000,000								47,000,000														47,000,000
Deferred Under Recovered Regulatory Clause Revenues [Member] | Alabama Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered certified PPA balance	29,000,000			29,000,000											29,000,000					29,000,000								29,000,000														29,000,000
Under recovered environmental clause	2,000,000			2,000,000											2,000,000					2,000,000								2,000,000														2,000,000
Prime Rate [Member] | Gulf Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Debt Instrument, Interest Rate, Stated Percentage	3.7947%			3.7947%											3.7947%					3.7947%								3.7947%														3.7947%
Settlement Agreement [Member] | Mississippi Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Other Income						7,000,000
Settlement Agreement [Member] | Gulf Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Other Cost of Removal Obligations	62,500,000			62,500,000											62,500,000					62,500,000								62,500,000														62,500,000
Current Estimate [Member] | Mississippi Power [Member] | Kemper IGCC [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost	4,930,000,000	[2]
Maximum cap construction cost	$ 6,200,000,000	[2],[3],[4]

[1] For additional information, see Note 3 under "Integrated Coal Gasification Combined Cycle – Rate Recovery of Kemper IGCC Costs – Regulatory Assets and Liabilities."

[2] 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. The Current Estimate and Actual Costs include non-incremental operating and maintenance costs related to the combined cycle and associated common facilities placed in service on August 9, 2014 that are subject to the $2.88 billion cost cap and excludes post-in-service costs for the lignite mine. See "Rate Recovery of Kemper IGCC Costs – 2013 MPSC Rate Order" for additional information.

[3] Recovered and amortized over the average remaining service period which may range up to 14 years. See Note 2 for additional information.

[4] Asset retirement and removal assets and liabilities and deferred income tax assets are recovered, and removal assets and deferred income tax liabilities are amortized over the related property lives, which may range up to 49 years. Asset retirement and removal assets and liabilities will be settled and trued up following completion of the related activities.