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Contingencies and Regulatory Matters (Details Textual) (USD $)
1 Months Ended 6 Months Ended 1 Months Ended 6 Months Ended 1 Months Ended 6 Months Ended 6 Months Ended 1 Months Ended 6 Months Ended 12 Months Ended 6 Months Ended 6 Months Ended
Apr. 30, 2009
Jul. 31, 2004
Jun. 30, 2011
Sep. 30, 2010
Alabama Power [Member]
Jul. 31, 2007
Alabama Power [Member]
Jun. 30, 2011
Alabama Power [Member]
Jul. 12, 2011
Alabama Power [Member]
Apr. 27, 2011
Alabama Power [Member]
Dec. 31, 2010
Alabama Power [Member]
Jul. 31, 2007
Georgia Power [Member]
Jun. 30, 2011
Georgia Power [Member]
Megawatts
Jun. 10, 2011
Georgia Power [Member]
May 24, 2011
Georgia Power [Member]
Feb. 21, 2011
Georgia Power [Member]
Jun. 30, 2011
Gulf Power [Member]
Jul. 08, 2011
Gulf Power [Member]
Dec. 31, 2010
Gulf Power [Member]
Nov. 30, 2010
Mississippi Power [Member]
May 31, 2009
Mississippi Power [Member]
Jun. 30, 2011
Mississippi Power [Member]
Dec. 31, 2008
Mississippi Power [Member]
May 05, 2011
Mississippi Power [Member]
Apr. 19, 2011
Mississippi Power [Member]
Mar. 04, 2011
Mississippi Power [Member]
Jan. 31, 2011
Mississippi Power [Member]
Dec. 31, 2010
Mississippi Power [Member]
Aug. 19, 2010
Mississippi Power [Member]
Jun. 30, 2011
Mississippi Power [Member]
MRA Revenue [Member]
Dec. 31, 2010
Mississippi Power [Member]
MRA Revenue [Member]
Jun. 30, 2011
Mississippi Power [Member]
MB Revenue [Member]
Dec. 31, 2010
Mississippi Power [Member]
MB Revenue [Member]
Contingencies and Regulatory Matters (Textuals) [Abstract]                                                              
Number of Coal Fired Generating Facilities at which New Source Review Violations Occurred           8                                                  
Number of dismissed claims against Alabama Power       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, lower range     $ 25,000                                                        
Civil penalties under Clean Air Act per day, upper range     37,500                                                        
No. of environmental group which filed complaint against the Southern Company   3                                                          
Number other electric power companies against which complaint is filed   4                                                          
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                     14,000,000       63,000,000                                
Number of PRPs filed separate actions 2                                                            
Agreements with plaintiffs in pending actions (in percentage)                                       95.00%                      
Claims awarded to companies related to nuclear fuel disposal litigation         17,000,000         30,000,000                                          
Unrecognized tax benefits of additional tax benefits recorded                       64,000,000                                      
Related regulatory liability                       62,000,000                                      
Reduction in related interest expense                       23,000,000                                      
Anticipates of elimination adjustment will result in additional revenues             30,000,000                                                
Anticipates of elimination adjustment will result in additional revenues with an annual effect             150,000,000                                                
Capacity of units used by Georgia Power to control fuel switch or retire remaining fossil generating units where environmental controls not yet install                     2,600                                        
Capacity of units used by Georgia Power more likely than others to switch fuel or control in time to comply with utility MACT Rule                     600                                        
Currently available capacity of unit not rely by Georgia Power in 2015                     2,000                                        
Capacity of units include application request by Georgia Power that country PSC certify purchase from four PPAs selected through 2015 request for proposal process                     1,562                                        
Estimated cost of scrubber project     625,000,000                                 312,500,000                      
Scrubber project expenditures amount     24,500,000                                 12,200,000                      
Ownership percentage in Scrubber project                             50.00%         50.00%                      
Condition for adjustment to the fuel cost recovery                             If the projected fuel cost over or under recovery balance at year-end exceeds 10% of the projected fuel revenue applicable for the period, Company is required to notify and indicate if an adjustment to the fuel cost recovery factor is being requested.                                
Under recovered fuel cost           35,000,000     4,000,000           18,900,000   17,400,000                            
Condition for adjustment to purchased power capacity recovery                             If the projected purchased power capacity cost over or under recovery balance at year-end exceeds 10% of the projected purchased power capacity revenue applicable for the period, Gulf Power is required to notify the Florida PSC and indicate an adjustment to the purchased power capacity cost recovery factor is being requested.                                
Over recovered purchased power capacity costs                             10,100,000   4,400,000                            
Approved amount for scrubber project                                           19,500,000                  
Amount approved for property damage reserve                                                 3,600,000            
Increase (decrease) in annual revenues                                       900,000                      
Percentage decrease in prior year annual retail revenue amount due to retail fuel cost recovery factor                                       5.00%                      
Amount of over recovered retail fuel costs included in the balance sheets                                       47,800,000           55,200,000          
Amount of over recovered MRA emissions allowance cost included in the balance sheets                                       600,000                      
Estimated cost associated with repairing damage facility to operation and maintenance expenses range               $40 million and 55 million                                              
Estimated cost associated with repairing damage facility to capital expenditure range               $135 million and 165 million                                              
Accumulated NDR reserve reflected as other regulatory liabilities, deferred           90,000,000                                                  
Establishment period                             5 years                                
Conservation goals covering period                             10 years                                
Percentage rate increase                                   1.936%                          
Rate increase amount                                   16,100,000                          
Percentage decrease in fuel rates requested with Georgia Public Service Commission                         0.61%                                    
Expected decrease in annual billings for fuel costs                         43,000,000                                    
Cost deferred in other regulatory assets                                       16,400,000                      
Previously expensed                                       1,000,000                      
Construction and capital costs included in semi-annual construction monitoring report made on Plant Vogtle Units 3 and 4                           1,050,000,000                                  
Projected financing costs to recover due to legislation                     1,680,000,000                                        
Reduction in projected in-service cost                     4,410,000,000                                        
Amortization to earnings of financing costs capitalized over the five year period                     91,000,000                                        
Costs included in construction work in progress                     82,000,000                 345,700,000                      
Generate additional gross annual revenues                             38,500,000                                
Additional gross annual revenues required to be generated by an increase in retail rates and charges                               93,500,000                              
Requested number of days to authorize collecting additional annual revenues                             60 days                                
Retail rate of return on common equity                               11.70%                              
Tax credits (Phase I)                                     133,000,000                        
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%                      
Accrued tax benefits on tax credits                                       51,700,000                      
Agreement reached to assign the remaining funds to the Kemper IGCC                                         270,000,000                    
Grant funds assigned to receive during initial operations of plant                                                     25,000,000        
Grant funds assigned to receive during construction of plant                                         245,000,000                    
Grant received for plant                                       111,700,000                      
Additional billed grant for plant                                       11,800,000                      
Percentage of Carbon dioxide captured from project by purchase Denbury                                               70.00%              
Percentage of contract to purchase carbon dioxide from Kemper IGCC                                               30.00%              
Cost incurred by Mississippi Power associated with plant including regulatory filing costs                                       488,200,000                      
Costs associated with CCP12 grant funds                                       123,500,000                      
Other deferred charges and assets                                       1,600,000                      
Cash Payment To Be Made In Conjunction With Purchase Of Facility                                       84,000,000                      
Debt Instrument Face Amount                                       270,000,000                      
Debt Instrument Interest Rate Stated Percentage                                       7.13%                      
Percentage annual decrease in revenue amount due to decrease in wholesale fuel rate                                                       3.50%   7.00%  
Amount of over recovered fuel costs                                                       $ 15,100,000 $ 17,500,000 $ 2,800,000 $ 4,400,000