Contingencies and Regulatory Matters - Textual (Details)												1 Months Ended									2 Months Ended	3 Months Ended							6 Months Ended	9 Months Ended		12 Months Ended								24 Months Ended	34 Months Ended	36 Months Ended		60 Months Ended
	Jan. 29, 2016 MW	Jan. 01, 2016 USD ($) $ / KWH_Kilowatt_hour	Dec. 03, 2015 USD ($)	Apr. 16, 2015 MW	Apr. 15, 2015 USD ($)	Apr. 01, 2015 USD ($)	Mar. 19, 2015 USD ($)	Jan. 01, 2014 USD ($)	Apr. 01, 2013 USD ($)	Mar. 19, 2013	Apr. 01, 2012 USD ($)	Dec. 31, 2015 USD ($) lawsuit mi	Nov. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Apr. 30, 2015 MW	May. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jul. 31, 2013 Customer MW	Feb. 28, 2013 USD ($)	Jan. 31, 2013 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) lawsuit mi	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) lawsuit mi	Sep. 30, 2016 MW	Sep. 30, 2015 USD ($)	Dec. 31, 2019	Dec. 31, 2018 $ / KWH_Kilowatt_hour	Dec. 31, 2017 $ / KWH_Kilowatt_hour	Dec. 31, 2015 USD ($) lawsuit mi $ / KWH_Kilowatt_hour MW	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2010	Dec. 31, 2008 MW	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) lawsuit mi	Dec. 31, 2017	Dec. 31, 2015 USD ($) lawsuit mi	Dec. 31, 2019	Dec. 31, 2016 USD ($)	Feb. 26, 2016 USD ($)	Feb. 01, 2016 USD ($)	Jan. 13, 2016 USD ($)	Dec. 15, 2015 USD ($)	Dec. 01, 2015 USD ($)	Nov. 02, 2015 USD ($)	Oct. 23, 2015 lawsuit	Oct. 06, 2015 USD ($)	Sep. 01, 2015 USD ($)	Aug. 13, 2015 USD ($)	Jul. 10, 2015 USD ($)	Jun. 03, 2015 USD ($)	May. 20, 2015 USD ($)	Feb. 19, 2015 USD ($)	Feb. 01, 2015	Dec. 01, 2014 USD ($)	Oct. 20, 2014 USD ($)	Oct. 06, 2014	Aug. 05, 2014 USD ($)	Aug. 01, 2014 MW	Jul. 01, 2014 MW	Aug. 31, 2013 USD ($)	May. 31, 2013 USD ($)	Mar. 31, 2013 USD ($)	Jan. 01, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 01, 2012 USD ($)	Jan. 01, 2012 USD ($)	Jan. 01, 2011 USD ($)
Retail Regulatory Matters [Abstract]
Other Regulatory Assets Current												$ 402,000,000									$ 346,000,000	$ 402,000,000				$ 346,000,000			$ 402,000,000						$ 402,000,000	$ 346,000,000				$ 346,000,000	$ 402,000,000		$ 402,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation												3,759,000,000					$ 2,018,000,000				2,201,000,000	3,759,000,000				2,201,000,000			3,759,000,000						3,759,000,000	2,201,000,000	$ 2,018,000,000			2,201,000,000	3,759,000,000		3,759,000,000
Unrecognized Tax Benefits												433,000,000					7,000,000				170,000,000	433,000,000				170,000,000			433,000,000						433,000,000	170,000,000	7,000,000			170,000,000	433,000,000		433,000,000																												$ 70,000,000
Interest-bearing refundable deposits												0									275,000,000	0				275,000,000			0						0	275,000,000				275,000,000	0		0
Other Cost of Removal Obligations												1,162,000,000									1,215,000,000	1,162,000,000				1,215,000,000			1,162,000,000						1,162,000,000	1,215,000,000				1,215,000,000	1,162,000,000		1,162,000,000
Other Regulatory Assets Deferred												4,989,000,000									4,334,000,000	4,989,000,000				4,334,000,000			4,989,000,000						4,989,000,000	4,334,000,000				4,334,000,000	4,989,000,000		4,989,000,000
Line of Credit Facility, Maximum Borrowing Capacity												6,505,000,000										6,505,000,000							6,505,000,000						6,505,000,000						6,505,000,000		6,505,000,000
Construction in Progress, Gross												$ 9,082,000,000									7,792,000,000	9,082,000,000				7,792,000,000			$ 9,082,000,000						9,082,000,000	7,792,000,000				7,792,000,000	$ 9,082,000,000		$ 9,082,000,000
Kemper IGCC [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Pre-Tax Charge To Income																						183,000,000	$ 150,000,000	$ 23,000,000	$ 9,000,000	70,000,000	$ 418,000,000	$ 380,000,000							365,000,000	868,000,000	1,200,000,000
After Tax Charge To Income																						$ 113,000,000	93,000,000	14,000,000	6,000,000	43,000,000	$ 258,000,000	235,000,000							$ 226,000,000	536,000,000	729,000,000
Parent And Mississippi Power [Member] | Kemper IGCC [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Pre-Tax Charge To Income																																					1,200,000,000
After Tax Charge To Income																																					729,000,000
AGL Resources [Member]
Loss Contingencies [Line Items]
Number of Class Action Lawsuits | lawsuit																																																				4
Parent Company and Merger Sub [Member]
Loss Contingencies [Line Items]
Number of Class Action Lawsuits | lawsuit												2										2							2						2						2		2
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												$ 653,000,000										$ 653,000,000							$ 653,000,000						$ 653,000,000						$ 653,000,000		$ 653,000,000
Alabama Power [Member]
Loss Contingencies [Line Items]
Percent Of Designated Customer Value Benchmark Survey																											33.30%
Nuclear Fuel Disposal Costs [Abstract]
Claims awarded to companies related to nuclear fuel disposal litigation							$ 26,000,000
Retail Regulatory Matters [Abstract]
Rate Adjustment Period																																			2 years
Maximum percentage of Rate RSE																																			4.00%
Maximum annual percentage of ratio rate																																			5.00%
Rate RSE Increase																																																													3.49%
Rate RSE Increase Amount																																																													$ 181,000,000
Adjusting Point Of Weighted Cost Of Equity																																																																			5.98%
Percent Of Basis Points																																																																			0.07%
Under recovered certified PPA balance												99,000,000										99,000,000							99,000,000						$ 99,000,000						99,000,000		99,000,000
Under Recovered Rate Cnp Balance																																																																			$ 75,000,000
Under recovered environmental clause												43,000,000										43,000,000							43,000,000						$ 43,000,000						43,000,000		43,000,000
Amortization of Regulatory Asset																					123,000,000
Regulatory Liability Amortization																					120,000,000
Approved billing rate under rate ECR up to (cents per KWH) | $ / KWH_Kilowatt_hour		0.02030																																	0.05910
Rate ECR Increase Decrease																																																		6.70%
Rate ECR Increase Decrease Amount																																																		$ 370,000,000
Future stated rates under rate Ecr factor in terms of per units | $ / KWH_Kilowatt_hour																																			0.02681
Over recovered fuel cost												238,000,000									47,000,000	238,000,000				47,000,000			238,000,000						$ 238,000,000	47,000,000				47,000,000	238,000,000		238,000,000
Deferred over recovered regulatory clause revenues												0									47,000,000	0				47,000,000			0						$ 0	47,000,000				47,000,000	0		0
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
Percentage Under Recovered Rate CNP Balance																																																																			1.50%
Deferral of maintenance costs																																			50,000,000
Other Regulatory Assets Current												$ 115,000,000									84,000,000	$ 115,000,000				84,000,000			$ 115,000,000						$ 115,000,000	84,000,000				84,000,000	$ 115,000,000		$ 115,000,000
Percent ownership												14.00%										14.00%							14.00%						14.00%						14.00%		14.00%
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation												$ 1,448,000,000					730,000,000				829,000,000	$ 1,448,000,000				829,000,000			$ 1,448,000,000						$ 1,448,000,000	829,000,000	730,000,000			829,000,000	$ 1,448,000,000		$ 1,448,000,000
Other Cost of Removal Obligations												722,000,000									744,000,000	722,000,000				744,000,000			722,000,000						722,000,000	744,000,000				744,000,000	722,000,000		722,000,000
Non-nuclear Outage Costs																																			95,000,000
Compliance And Pension Costs																																			28,000,000
Other Regulatory Assets Deferred												1,114,000,000									1,063,000,000	1,114,000,000				1,063,000,000			1,114,000,000						1,114,000,000	1,063,000,000				1,063,000,000	1,114,000,000		1,114,000,000
Line of Credit Facility, Maximum Borrowing Capacity												1,340,000,000										1,340,000,000							1,340,000,000						1,340,000,000						1,340,000,000		1,340,000,000
Construction in Progress, Gross												$ 801,000,000									1,006,000,000	$ 801,000,000				1,006,000,000			$ 801,000,000						$ 801,000,000	1,006,000,000				1,006,000,000	$ 801,000,000		$ 801,000,000
Alabama Power [Member] | Scenario, Forecast [Member]
Retail Regulatory Matters [Abstract]
Future stated rates under rate Ecr factor in terms of per units | $ / KWH_Kilowatt_hour																																	0.05910	0.02681
Alabama Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity												5.75%										5.75%							5.75%						5.75%						5.75%		5.75%																								5.75%
Alabama Power [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Weighted Cost Of Equity												6.21%										6.21%							6.21%						6.21%						6.21%		6.21%																								6.21%
Alabama Power [Member] | Fuel Recovery Clause [Member]
Retail Regulatory Matters [Abstract]
Deferred over recovered regulatory clause revenues												$ 238,000,000										$ 238,000,000							$ 238,000,000						$ 238,000,000						$ 238,000,000		$ 238,000,000
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 | MW															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 | MW															300
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 | MW															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 | MW																																			225
Alabama Power [Member] | Plant Farley [Member]
Retail Regulatory Matters [Abstract]
Recovery Amount From Customers Associated With Permanent Disposal Of Nuclear Waste												20,000,000										20,000,000							20,000,000						$ 20,000,000						20,000,000		20,000,000																					$ 14,000,000
Georgia Power [Member]
Loss Contingencies [Line Items]
Increase In NCCR Tariff								$ 60,000,000																																										$ 27,000,000																				$ 50,000,000			$ 35,000,000	$ 223,000,000
Environmental Matters [Abstract]
Environmental remediation liability												29,000,000										29,000,000							29,000,000						$ 29,000,000						29,000,000		29,000,000
Nuclear Fuel Disposal Costs [Abstract]
Claims awarded to companies related to nuclear fuel disposal litigation							$ 18,000,000
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																																			$ 14,000,000	14,000,000	31,000,000
Retail Rate of Return on Common Equity								10.95%
Period for Environmental Construction								9 years																											9 years
Other Regulatory Assets Current												123,000,000									136,000,000	123,000,000				136,000,000			123,000,000						$ 123,000,000	136,000,000				136,000,000	123,000,000		123,000,000
Estimated In-service Capital Cost																																			4,400,000,000
Amendment To Estimated In-service Capital Cost																																			4,800,000,000
Revenue Subject To Refund																																			11,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation												1,916,000,000					1,222,000,000				1,255,000,000	1,916,000,000				1,255,000,000			1,916,000,000						1,916,000,000	1,255,000,000	1,222,000,000			1,255,000,000	1,916,000,000		1,916,000,000
Unrecognized Tax Benefits												3,000,000					$ 0				0	3,000,000				0			3,000,000						3,000,000	0	0			0	3,000,000		3,000,000																												23,000,000
Other Cost of Removal Obligations												16,000,000									46,000,000	16,000,000				46,000,000			16,000,000						16,000,000	46,000,000				46,000,000	16,000,000		16,000,000
Number Of Intervenors Approved ARP																	11
Number of Intervenors																	13
Increase (Decrease) in Base Tariff Rate								$ 80,000,000																																									$ 49,000,000										$ 107,000,000
Increase (Decrease) In ECCR Tariff								25,000,000																																									75,000,000										23,000,000
Increase (Decrease) In Demand Side Management Tariff								1,000,000																																									3,000,000										3,000,000
Increase (Decrease) In Municipal Franchise Fee Tariff								4,000,000																																									13,000,000										3,000,000
Increase (Decrease) in Revenue to be Received from Base Rate Change								$ 110,000,000																																									140,000,000										$ 136,000,000
Approved Increase in Annual Billing Based on Fuel Cost Recovery Rate																																																	$ 350,000,000																					$ 122,000,000		$ 567,000,000
Adjustment To Fuel Cost Recovery Rate If Under Recovered Fuel Balance Exceeds Budget Thereafter																																			$ 200,000,000
Required Period For Options And Hedges																																			48 months
Over Recovered Fuel Balance												116,000,000									199,000,000	116,000,000				199,000,000			116,000,000						$ 116,000,000	199,000,000				199,000,000	116,000,000		116,000,000
Accrual Under Alternate Rate Plan																																			30,000,000
Other Regulatory Assets Deferred												2,152,000,000									1,753,000,000	2,152,000,000				1,753,000,000			2,152,000,000						2,152,000,000	1,753,000,000				1,753,000,000	2,152,000,000		2,152,000,000
Electric Generating Capacity in Mega Watts Under Consortium Agreement | MW																																							1,100
Additional Construction Capital Costs																													5,440,000,000						$ 160,000,000					3,100,000,000
Delay Of Estimated In-service Date																																			18 months
Percentage of Proportionate Share Owed in Consortium Agreement																																			45.70%
Line of Credit Facility, Maximum Borrowing Capacity												1,750,000,000										1,750,000,000							1,750,000,000						$ 1,750,000,000						1,750,000,000		1,750,000,000
Increase (Decrease) In Projected Certified Construction Capital Costs																																			5.00%
Construction in Progress, Gross												$ 4,775,000,000									4,031,000,000	$ 4,775,000,000				4,031,000,000			$ 4,775,000,000						$ 4,775,000,000	4,031,000,000				4,031,000,000	$ 4,775,000,000		$ 4,775,000,000
Georgia Power [Member] | Subsequent Event [Member]
Loss Contingencies [Line Items]
Increase In NCCR Tariff		$ 19,000,000
Retail Regulatory Matters [Abstract]
Capacity Of Units Included in Application Request By Subsidiaries For Future Period Requests | MW																														525
Georgia Power [Member] | Intercession City Combustion Turbine [Member]
Retail Regulatory Matters [Abstract]
Percent ownership												33.30%										33.30%							33.30%						33.30%						33.30%		33.30%
Georgia Power [Member] | Intercession City Combustion Turbine [Member] | Subsequent Event [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request To Sell | MW	143
Georgia Power [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Retail Rate of Return on Common Equity								10.00%
Estimated In-service Capital Cost					$ 4,400,000,000
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
Georgia Power [Member] | Property damage reserves-liability [Member]
Retail Regulatory Matters [Abstract]
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		$ 30,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Other Regulatory Assets Deferred												62,000,000									68,000,000	62,000,000				68,000,000			62,000,000						62,000,000	68,000,000				68,000,000	62,000,000		62,000,000
Regulatory asset												92,000,000									98,000,000	92,000,000				98,000,000			92,000,000						92,000,000	98,000,000				98,000,000	92,000,000		92,000,000
Georgia Power [Member] | Storm Costs [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Regulatory asset												92,000,000									98,000,000	92,000,000				98,000,000			92,000,000						92,000,000	98,000,000				98,000,000	92,000,000		92,000,000
Georgia Power [Member] | Plant Branch Units 1 and 3 and 4 [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units | MW				1,266
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																																			27,000,000
Construction Financing Costs																															$ 2,400,000,000				2,400,000,000
Construction in Progress, Gross												3,600,000,000										3,600,000,000							3,600,000,000						3,600,000,000						3,600,000,000		3,600,000,000
Georgia Power [Member] | Plant Yates [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units | MW																		579
Georgia Power [Member] | Plant McManus [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units | MW																		122
Georgia Power [Member] | Plant Kraft [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Units Approved For Decertification Of Units | MW																		316
Georgia Power [Member] | Plant Mitchell Units 3, 4A, and 4B [Member] | Subsequent Event [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units | MW	217
Georgia Power [Member] | Plant Kraft Unit 1 [Member] | Subsequent Event [Member]
Retail Regulatory Matters [Abstract]
Capacity Of Units Included In Request by Subsidiaries For Decertification Of Units | MW	17
Georgia Power [Member] | Plant Mitchell [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Capacity Of Small Power Production Facility | MW																																																																		155
Mississippi Power [Member]
FERC Matters [Abstract]
Increase in Annual Base Wholesale Revenues											$ 23,000,000
Period Over Which Annual Revenue Will Increase Under Tariff											12 months
Increase in Base Rate Under Cost Based Electric Tariff Due to Settlement									$ 24,000,000							$ 10,000,000
Retail Regulatory Matters [Abstract]
Anticipates of elimination adjustment will result in additional revenues																																				3,000,000
PSC Approved Annual Property Damage Reserve Accrual																																																					$ 3,000,000
Annual PEP Lookback Refund To Customers																																																																				$ 5,000,000
Over recovered fuel cost																					3,000,000					3,000,000										3,000,000				3,000,000
Other Regulatory Assets Current												95,000,000									73,000,000	95,000,000				73,000,000			95,000,000						95,000,000	73,000,000				73,000,000	95,000,000		95,000,000
Costs included in CWIP												3,470,000,000										3,470,000,000							3,470,000,000						3,470,000,000						3,470,000,000		3,470,000,000
Required Customers For Energy Efficiency Programs | Customer																		25,000
Required Period For Filing Quick Start Plans																		6 months
Percentage Of PSC Retail Rate Increase																																																						0.35%
Project expenditures, cumulative												637,000,000										637,000,000							637,000,000						637,000,000						637,000,000		637,000,000
Project expenditures, cumulative, proportionate share												325,000,000										325,000,000							325,000,000						325,000,000						325,000,000		325,000,000
AFUDC Cost						$ 14,000,000																													36,000,000
PSC Retail Rate Increase																																																						$ 2,000,000								$ 7,000,000
System Restoration Rider Rate																																																												0.00%
Regulatory Liabilities												$ 2,000,000										$ 2,000,000							$ 2,000,000						$ 2,000,000						$ 2,000,000		$ 2,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Plant capacity under coal gasification combined cycle technology in Mega Watts | MW																																			582
New Co2 Pipeline Infrastructure | mi												61										61							61						61						61		61
Costs Related to Grant Funding																	$ 245,000,000																				245,000,000
Maximum cap construction cost																				$ 2,880,000,000
Retail Rate Recovery																																			$ 371,000,000								$ 342,000,000
Carrying Costs Associated With Retail Rate Recovery																																									$ 29,000,000
Costs included in CWIP												$ 3,470,000,000										$ 3,470,000,000							$ 3,470,000,000						3,470,000,000						3,470,000,000		3,470,000,000
Loss Contingency, Estimate of Possible Loss												2,410,000,000										2,410,000,000							2,410,000,000						2,410,000,000						2,410,000,000		2,410,000,000
Other Property And Investments												2,000,000										2,000,000							2,000,000						2,000,000						2,000,000		2,000,000
Prepaid Supplies												45,000,000										45,000,000							45,000,000						45,000,000						45,000,000		45,000,000
Cost deferred in other regulatory assets												21,000,000										21,000,000							21,000,000						21,000,000						21,000,000		21,000,000
Other deferred charges and assets												11,000,000										11,000,000							11,000,000						11,000,000						11,000,000		11,000,000
Asset Retirement Obligation												177,000,000					42,000,000				48,000,000	177,000,000				48,000,000			177,000,000						177,000,000	48,000,000	42,000,000			48,000,000	177,000,000		177,000,000
Lignite Mining Costs												69,000,000										69,000,000							69,000,000						69,000,000						69,000,000		69,000,000
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
Unrecognized Tax Benefits												$ 421,000,000					4,000,000				165,000,000	$ 421,000,000				165,000,000			$ 421,000,000						$ 421,000,000	165,000,000	$ 4,000,000			165,000,000	$ 421,000,000		$ 421,000,000																												$ 6,000,000
Reduced Percentage Interest Transferred under Asset Purchase Agreement																																					15.00%
Term of management fee contract																																			40 years
Percentage of Carbon dioxide captured from project 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%
Interest-bearing refundable deposits												$ 0									275,000,000	$ 0				275,000,000			$ 0						$ 0	275,000,000				275,000,000	$ 0		$ 0															$ 275,000,000
Return Of Interest Bearing Refundable Deposits Related to Assets Sale Plus Accrued Interest												301,000,000	$ 375,000,000																						301,000,000	0	$ 0
Tax credits (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%
Period Of Bonus Depreciation Extension																																			5 years
Annual PEP Filing Rate Increase																																																																					1.90%
Annual PEP Filing Rate Increase Amount																																																																					$ 15,000,000
Debt Instrument, Interest Rate, Stated Percentage																																																																							7.13%
Other Cost of Removal Obligations												165,000,000									166,000,000	165,000,000				166,000,000			165,000,000						$ 165,000,000	166,000,000				166,000,000	165,000,000		165,000,000
Other Regulatory Assets Deferred												525,000,000									385,000,000	525,000,000				385,000,000			525,000,000						525,000,000	385,000,000				385,000,000	525,000,000		525,000,000
Line of Credit Facility, Maximum Borrowing Capacity												220,000,000										220,000,000							220,000,000						220,000,000						220,000,000		220,000,000
Construction in Progress, Gross												$ 2,254,000,000									$ 2,161,000,000	$ 2,254,000,000				2,161,000,000			$ 2,254,000,000						$ 2,254,000,000	2,161,000,000				$ 2,161,000,000	$ 2,254,000,000		$ 2,254,000,000
Mississippi Power [Member] | Subsequent Event [Member]
Retail Regulatory Matters [Abstract]
Proposed Change in Annual Revenues		$ 47,000,000																																													$ 2,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Period Of Bonus Depreciation Extension																																												5 years
Bonus Depreciation for Property Acquired																																30.00%	40.00%									50.00%
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												$ 120,000,000										$ 120,000,000							$ 120,000,000						$ 120,000,000						$ 120,000,000		$ 120,000,000
Under Recovered Fuel Cost												71,000,000										71,000,000							71,000,000						71,000,000						71,000,000		71,000,000
Mississippi Power [Member] | MRA Revenue [Member]
Retail Regulatory Matters [Abstract]
Over recovered fuel cost												$ 24,000,000										$ 24,000,000							$ 24,000,000						$ 24,000,000						$ 24,000,000		$ 24,000,000
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%
Mississippi Power [Member] | Electricity Generation Plant, Non-Nuclear [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost																				$ 2,440,000,000
Alternate Financing																			$ 1,000,000,000
Mississippi Power [Member] | Kemper IGCC [Member]
Retail Regulatory Matters [Abstract]
Other Regulatory Assets Current												$ 96,000,000										$ 96,000,000							$ 96,000,000						$ 96,000,000						$ 96,000,000		$ 96,000,000
AFUDC Cost						$ 11,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Cost																																			4,830,000,000
Maximum cap construction cost																																			6,030,000,000
Monthly Charge Of Allowance For Equity Funds Used During Construction																																			13,000,000
Monthly Cost, Regulatory Assets and Other																																			2,000,000
Asset Retirement Obligation												11,000,000										11,000,000							11,000,000						11,000,000						11,000,000		11,000,000
Pre-Tax Charge To Income																						183,000,000	150,000,000	23,000,000	9,000,000	70,000,000	$ 418,000,000	380,000,000							365,000,000	868,000,000	1,100,000,000
After Tax Charge To Income																						113,000,000	$ 93,000,000	$ 14,000,000	$ 6,000,000	$ 43,000,000	$ 258,000,000	$ 235,000,000							226,000,000	$ 536,000,000	681,000,000
Unrecognized Tax Benefits												$ 423,000,000										$ 423,000,000							$ 423,000,000						$ 423,000,000						$ 423,000,000		$ 423,000,000
Purchase of interest in plant												100.00%										100.00%							100.00%						100.00%						100.00%		100.00%																				15.00%
Positive Impact From Bonus Depreciation												$ 3,000,000										$ 3,000,000							$ 3,000,000						$ 3,000,000						$ 3,000,000		$ 3,000,000
Other Regulatory Assets Deferred												195,000,000										195,000,000							195,000,000						195,000,000						195,000,000		195,000,000
Regulatory asset												120,000,000										120,000,000							120,000,000						120,000,000						120,000,000		120,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Subsequent Event [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Positive Impact From Bonus Depreciation																																													$ 360,000,000
Mississippi Power [Member] | Kemper IGCC [Member] | Minimum [Member]
Retail Regulatory Matters [Abstract]
Estimated In-service Capital Cost																																			$ 25,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Amortization Period of Regulatory Assets and Liabilities																																			2 years
Mississippi Power [Member] | Kemper IGCC [Member] | Maximum [Member]
Retail Regulatory Matters [Abstract]
Estimated In-service Capital Cost																																			$ 35,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Amortization Period of Regulatory Assets and Liabilities																																			10 years
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 | MW																																																																	80
Mississippi Power [Member] | Plant Watson Units 4 And 5 [Member]
Retail Regulatory Matters [Abstract]
Capacity Unit Conversion To Non-fossil Fuel Source | MW																																																																	750
Mississippi Power [Member] | Plant Greene County Units 1 And 2 [Member]
Retail Regulatory Matters [Abstract]
Costs included in CWIP												5,000,000										5,000,000							5,000,000						$ 5,000,000						5,000,000		5,000,000
Capacity Unit Conversion To Non-fossil Fuel Source | MW																																																																	200
Integrated Coal Gasification Combined Cycle [Abstract]
Costs included in CWIP												5,000,000										5,000,000							5,000,000						5,000,000						5,000,000		5,000,000
Mississippi Power [Member] | Plant Watson [Member]
Retail Regulatory Matters [Abstract]
Costs included in CWIP												36,000,000										36,000,000							36,000,000						36,000,000						36,000,000		36,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Costs included in CWIP												36,000,000										36,000,000							36,000,000						36,000,000						36,000,000		36,000,000
Gulf Power [Member]
Environmental Matters [Abstract]
Environmental remediation liability												46,000,000										46,000,000							46,000,000						46,000,000						46,000,000		46,000,000
Retail Regulatory Matters [Abstract]
PSC Approved Annual Property Damage Reserve Accrual												$ 3,500,000										$ 3,500,000							$ 3,500,000						$ 3,500,000						$ 3,500,000		$ 3,500,000
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%				10.25%
Other Regulatory Assets Current												$ 90,000,000									$ 74,000,000	$ 90,000,000				$ 74,000,000			$ 90,000,000						$ 90,000,000	$ 74,000,000				$ 74,000,000	$ 90,000,000		$ 90,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Asset Retirement Obligation												130,000,000					$ 16,000,000				17,000,000	130,000,000				17,000,000			130,000,000						130,000,000	17,000,000	$ 16,000,000			17,000,000	130,000,000		130,000,000
Estimated Cost of Project One												316,000,000										316,000,000							316,000,000						$ 316,000,000						316,000,000		316,000,000
Base Revenue In Year One																					35,000,000					35,000,000										35,000,000				35,000,000
Base Revenue In Year Two																					20,000,000					20,000,000										20,000,000				20,000,000
Period of Treasury Rate Above Basis Points																																			6 months
Other Cost of Removal Obligations												233,000,000									235,000,000	233,000,000				235,000,000			233,000,000						$ 233,000,000	235,000,000				235,000,000	233,000,000		233,000,000
Reduction In Depreciation Expense																																			$ 8,400,000	20,100,000
Retail Rate Increase (Decrease)																																																			$ 49,000,000
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												427,000,000									416,000,000	427,000,000				416,000,000			427,000,000						$ 427,000,000	416,000,000				416,000,000	427,000,000		427,000,000
Line of Credit Facility, Maximum Borrowing Capacity												275,000,000										275,000,000							275,000,000						275,000,000						275,000,000		275,000,000
Construction in Progress, Gross												$ 48,000,000									$ 465,000,000	$ 48,000,000				$ 465,000,000			$ 48,000,000						$ 48,000,000	$ 465,000,000				$ 465,000,000	$ 48,000,000		$ 48,000,000
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%
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%				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%				11.25%
Under Recovered Regulatory Clause Revenues and Other Current Liabilities [Member] | Gulf Power [Member]
Environmental Matters [Abstract]
Environmental remediation liability												$ 4,000,000										$ 4,000,000							$ 4,000,000						$ 4,000,000						$ 4,000,000		$ 4,000,000
Other Regulatory Assets, Deferred and Other Deferred Credits and Liabilities [Member] | Gulf Power [Member]
Environmental Matters [Abstract]
Environmental remediation liability												42,000,000										42,000,000							42,000,000						42,000,000						42,000,000		42,000,000
Other regulatory liabilities current [Member] | Gulf Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered fuel balance																					$ 40,000,000					$ 40,000,000										$ 40,000,000				$ 40,000,000
Regulatory Clause Revenues, under-recovered [Member] | Gulf Power [Member]
Retail Regulatory Matters [Abstract]
Under recovered fuel balance												18,000,000										18,000,000							18,000,000						18,000,000						18,000,000		18,000,000
Integrated Coal Gasification Combined Cycle [Abstract]
Under Recovered Environmental Cost																					10,000,000					10,000,000										10,000,000				10,000,000
Under Recovered Energy Conservation Costs												$ 4,000,000									$ 3,000,000	$ 4,000,000				$ 3,000,000			$ 4,000,000						$ 4,000,000	$ 3,000,000				$ 3,000,000	$ 4,000,000		$ 4,000,000
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%
Plant Vogtle Units 3 And 4 [Member] | Georgia Power [Member] | Subsequent Event [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity																																																$ 900,000,000
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																																			5,290,000,000
Maximum cap construction cost																																			6,630,000,000
Pending Litigation [Member] | Plant Vogtle Units 3 And 4 [Member] | Georgia Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Project Settlement Cost To Be Capitalized												350,000,000										350,000,000							350,000,000						350,000,000						350,000,000		350,000,000
Project Settlement Cost To Be Capitalized, Amount Paid To Date												$ 120,000,000										$ 120,000,000							$ 120,000,000						$ 120,000,000						$ 120,000,000		120,000,000
Pending Litigation [Member] | Plant Vogtle Units 3 And 4 [Member] | Georgia Power [Member] | Subsequent Event [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Project Settlement Cost To Be Capitalized, Amount Paid To Date																																														$ 121,000,000
Pending Litigation [Member] | Plant Vogtle Units 3 And 4 [Member] | Georgia Power [Member] | Minimum [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Estimated Adjustment to Contract Price Related to Issues that May Impact Project Budget and Schedule														$ 714,000,000
In-Service Asset Proposal [Member] | Mississippi Power [Member] | Kemper IGCC [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
PSC Retail Rate Increase (Decrease)			$ 126,000,000																																																				$ 159,000,000	$ 159,000,000
Public Utilities, Approved Equity Capital Structure, Percentage			49.733%
Public Utilities, Approved Return on Equity, Percentage			9.225%
Customer Refund																																											$ 11,000,000
Period to File Subsequent Rate Request			18 months
Interest Bearing Refundable Deposit Related To Assets Sale [Member] | Mississippi Power [Member]
Integrated Coal Gasification Combined Cycle [Abstract]
Debt Instrument, Interest Amount																																																									$ 26,000,000