Common Stock and Stock Compensation - Stock Option Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Option, Outstanding, Beginning Balance	40,956,822
Shares Subject to Option, Granted	7,153,669
Shares Subject to Option, Exercised	(12,120,419)
Shares Subject to Options, Cancelled	(73,769)
Shares Subject to Option, Outstanding, Ending Balance	35,916,303
Shares Subject to Options, Exercisable, Ending Balance	22,724,015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 33.88
Options Granted, Weighted Average Exercise Price	$ 44.50
Options Exercised, Weighted Average Exercise Price	$ 32.76
Options Cancelled, Weighted Average Exercise Price	$ 37.75
Options Outstanding, Weighted Average Exercise Price, End of Period	$ 36.37
Options Exercisable, Weighted Average Exercise Price, End of Period	$ 34.09
Mississippi Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Option, Outstanding, Beginning Balance	1,569,728
Shares Subject to Option, Granted	278,709
Shares Subject to Option, Exercised	(474,871)
Shares Subject to Options, Cancelled	0
Shares Subject to Option, Outstanding, Ending Balance	1,373,566
Shares Subject to Options, Exercisable, Ending Balance	864,634
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 0
Options Granted, Weighted Average Exercise Price	$ 0
Options Exercised, Weighted Average Exercise Price	$ 0
Options Cancelled, Weighted Average Exercise Price	$ 0
Options Outstanding, Weighted Average Exercise Price, End of Period	$ 0
Options Exercisable, Weighted Average Exercise Price, End of Period	$ 0
Gulf Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Option, Outstanding, Beginning Balance	1,498,663
Shares Subject to Option, Granted	244,607
Shares Subject to Option, Exercised	(353,749)
Shares Subject to Options, Cancelled	(606)
Shares Subject to Option, Outstanding, Ending Balance	1,388,915
Shares Subject to Options, Exercisable, Ending Balance	884,888
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 33.75
Options Granted, Weighted Average Exercise Price	$ 44.43
Options Exercised, Weighted Average Exercise Price	$ 31.97
Options Cancelled, Weighted Average Exercise Price	$ 42.08
Options Outstanding, Weighted Average Exercise Price, End of Period	$ 36.08
Options Exercisable, Weighted Average Exercise Price, End of Period	$ 34.02
Georgia Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Option, Outstanding, Beginning Balance	7,952,587
Shares Subject to Option, Granted	1,269,725
Shares Subject to Option, Exercised	(2,666,146)
Shares Subject to Options, Cancelled	(8,668)
Shares Subject to Option, Outstanding, Ending Balance	6,547,498
Shares Subject to Options, Exercisable, Ending Balance	4,196,637
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 33,730,000
Options Granted, Weighted Average Exercise Price	$ 44,430,000
Options Exercised, Weighted Average Exercise Price	$ 32,770,000
Options Cancelled, Weighted Average Exercise Price	$ 42,040,000
Options Outstanding, Weighted Average Exercise Price, End of Period	$ 36,180,000
Options Exercisable, Weighted Average Exercise Price, End of Period	$ 33,960,000
Alabama Power [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares Subject to Option, Outstanding, Beginning Balance	7,191,786
Shares Subject to Option, Granted	1,099,315
Shares Subject to Option, Exercised	(2,226,269)
Shares Subject to Options, Cancelled	(4,280)
Shares Subject to Option, Outstanding, Ending Balance	6,060,552
Shares Subject to Options, Exercisable, Ending Balance	3,884,089
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options Outstanding, Weighted Average Exercise Price, Beginning of Period	$ 33.63
Options Granted, Weighted Average Exercise Price	$ 44.44
Options Exercised, Weighted Average Exercise Price	$ 32.43
Options Cancelled, Weighted Average Exercise Price	$ 38.74
Options Outstanding, Weighted Average Exercise Price, End of Period	$ 36.02
Options Exercisable, Weighted Average Exercise Price, End of Period	$ 33.84