Financing (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Credit arrangements by company
Expires, 2013	$ 361	[1]
Expires, 2014	236	[1]
Expires, 2016	480	[1]
Expires, 2018	4,100	[1]
Total	5,177
Unused	5,167
Executable Term-Loans, One Year	151
Executable Term-Loans, Two Years	40
Due Within One Year, Term Out	191
Due Within One Year, No Term Out	227
Southern Company [Member]
Credit arrangements by company
Expires, 2013	0	[1]
Expires, 2014	0	[1]
Expires, 2016	0	[1]
Expires, 2018	1,000	[1]
Total	1,000
Unused	1,000
Executable Term-Loans, One Year	0
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	0
Due Within One Year, No Term Out	0
Alabama Power [Member]
Credit arrangements by company
Expires, 2013	156	[1]
Expires, 2014	151	[1]
Expires, 2016	0	[1]
Expires, 2018	1,000	[1]
Total	1,307
Unused	1,307
Executable Term-Loans, One Year	56
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	56
Due Within One Year, No Term Out	102
Line of Credit Facility, Amount Outstanding	200
Georgia Power [Member]
Credit arrangements by company
Expires, 2013	0	[1]
Expires, 2014	0	[1]
Expires, 2016	150	[1]
Expires, 2018	1,600	[1]
Total	1,750
Unused	1,740
Executable Term-Loans, One Year	0
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	0
Due Within One Year, No Term Out	0
Gulf Power [Member]
Credit arrangements by company
Expires, 2013	45	[1]
Expires, 2014	60	[1]
Expires, 2016	165	[1]
Expires, 2018	0	[1]
Total	270
Unused	270
Executable Term-Loans, One Year	45
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	45
Due Within One Year, No Term Out	30
Line of Credit Facility, Amount Outstanding	30
Line of Credit Facility, Maximum Amount Outstanding During Period	35
Line of Credit, Current	5
Mississippi Power [Member]
Credit arrangements by company
Expires, 2013	110	[1]
Expires, 2014	25	[1]
Expires, 2016	165	[1]
Expires, 2018	0	[1]
Total	300
Unused	300
Executable Term-Loans, One Year	25
Executable Term-Loans, Two Years	40
Due Within One Year, Term Out	65
Due Within One Year, No Term Out	70
Southern Power [Member]
Credit arrangements by company
Expires, 2013	0	[1]
Expires, 2014	0	[1]
Expires, 2016	0	[1]
Expires, 2018	500	[1]
Total	500
Unused	500
Executable Term-Loans, One Year	0
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	0
Due Within One Year, No Term Out	0
Other Subsidiaries [Member]
Credit arrangements by company
Expires, 2013	50	[1]
Expires, 2014	0	[1]
Expires, 2016	0	[1]
Expires, 2018	0	[1]
Total	50
Unused	50
Executable Term-Loans, One Year	25
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	25
Due Within One Year, No Term Out	25
SEGCO [Member]
Credit arrangements by company
Line of Credit Facility, Amount Outstanding	$ 25
Number Of Credit Arrangements	2

[1] No credit arrangements expire in 2015 or 2017.