Nuclear Insurance (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2012
Jointly Owned Utility Plant Interests [Line Items]
Maximum fund for public liability claims arising from a single nuclear incident under Price-Anderson Amendments Act		$ 12,600,000,000
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant		375,000,000
Maximum amount that a company could be assessed per incident for each licensed reactor		117,500,000
Maximum aggregate amount that a reactor can assess in a calendar period for each incident		17,500,000
Maximum aggregate amount to be paid in one year		35,000,000
Block period considered for inflation adjustment against maximum assessment per reactor		5 years
Block period considered for inflation adjustment against maximum yearly assessment		5 years
Frequency of Indemnity Payments		Weekly over a three year period
Maximum property damage insurance provided to nuclear generating facilities		500,000,000
Maximum additional coverage provided for losses under excess insurance		2,250,000,000
Maximum deductible waiting period		26 weeks
Maximum coverage per occurrence per unit limit to obtain replacement power		490,000,000
Approximate period over which maximum per occurrence per unit limit is exhausted		3 years
Aggregate payment for claims resulting from terrorist acts in one year period		3,200,000,000
Vogtle Units 3 and 4 [Member]
Jointly Owned Utility Plant Interests [Line Items]
Maximum limits for accidental property damage occurring during construction		2,750,000,000
Alabama Power [Member]
Jointly Owned Utility Plant Interests [Line Items]
Maximum fund for public liability claims arising from a single nuclear incident under Price-Anderson Amendments Act		12,600,000,000
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant		375,000,000
Maximum amount that a company could be assessed per incident for each licensed reactor		117,500,000
Maximum aggregate amount that a reactor can assess in a calendar period for each incident		17,500,000
Maximum assessment, excluding any applicable state premium taxes		235,000,000
Maximum aggregate amount to be paid in one year		35,000,000
Block period considered for inflation adjustment against maximum assessment per reactor		5 years
Block period considered for inflation adjustment against maximum yearly assessment		5 years
Maximum property damage insurance provided to nuclear generating facilities		500,000,000
Maximum additional coverage provided for losses under excess insurance		2,250,000,000
Maximum deductible waiting period		26 weeks
Maximum coverage per occurrence per unit limit to obtain replacement power		490,000,000
Approximate period over which maximum per occurrence per unit limit is exhausted		3 years
Elected deductible waiting period	12-week
Current maximum annual assessments under NEIL policies		42,000,000
Aggregate payment for claims resulting from terrorist acts in one year period		3,200,000,000
Georgia Power [Member]
Jointly Owned Utility Plant Interests [Line Items]
Maximum fund for public liability claims arising from a single nuclear incident under Price-Anderson Amendments Act		12,600,000,000
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant		375,000,000
Maximum amount that a company could be assessed per incident for each licensed reactor		117,500,000
Maximum aggregate amount that a reactor can assess in a calendar period for each incident		17,500,000
Maximum assessment, excluding any applicable state premium taxes		232,000,000
Maximum aggregate amount to be paid in one year		35,000,000
Block period considered for inflation adjustment against maximum assessment per reactor		5 years
Block period considered for inflation adjustment against maximum yearly assessment		5 years
Maximum property damage insurance provided to nuclear generating facilities		500,000,000
Maximum additional coverage provided for losses under excess insurance		2,250,000,000
Maximum deductible waiting period		26 weeks
Maximum coverage per occurrence per unit limit to obtain replacement power		490,000,000
Approximate period over which maximum per occurrence per unit limit is exhausted		3 years
Elected deductible waiting period	12-week	12-week
Current maximum annual assessments under NEIL policies		70,000,000
Aggregate payment for claims resulting from terrorist acts in one year period		3,200,000,000
Vogtle Units 3 and 4 [Member] | Georgia Power [Member]
Jointly Owned Utility Plant Interests [Line Items]
Maximum limits for accidental property damage occurring during construction		$ 2,750,000,000