Financing (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013
Credit arrangements by company
Expires, 2013	$ 36	[1]
Expires, 2014	553	[1]
Expires, 2015	60	[1]
Expires, 2016	480	[1]
Expires, 2018	4,100	[1]
Total	5,229
Unused	5,201
Executable Term-Loans, One Year	148
Executable Term-Loans, Two Years	40
Due Within One Year, Term Out	188
Due Within One Year, No Term Out	331
Southern Company [Member]
Credit arrangements by company
Expires, 2013	0	[1]
Expires, 2014	0	[1]
Expires, 2015	0
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	1	[1]
Expires, 2014	268	[1]
Expires, 2015	35
Expires, 2016	0	[1]
Expires, 2018	1,000	[1]
Total	1,304
Unused	1,304
Executable Term-Loans, One Year	53
Executable Term-Loans, Two Years	0
Due Within One Year, Term Out	53
Due Within One Year, No Term Out	146
Georgia Power [Member]
Credit arrangements by company
Expires, 2013	0	[1]
Expires, 2014	0	[1]
Expires, 2015	0
Expires, 2016	150	[1]
Expires, 2018	1,600	[1]
Total	1,750
Unused	1,736
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	20	[1]
Expires, 2014	90	[1]
Expires, 2015	0
Expires, 2016	165	[1]
Expires, 2018	0	[1]
Total	275
Unused	275
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	65
Mississippi Power [Member]
Credit arrangements by company
Expires, 2013	15	[1]
Expires, 2014	120	[1]
Expires, 2015	0
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, 2015	0
Expires, 2016	0	[1]
Expires, 2018	500	[1]
Total	500
Unused	486
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	0	[1]
Expires, 2014	75	[1]
Expires, 2015	25
Expires, 2016	0	[1]
Expires, 2018	0	[1]
Total	100
Unused	100
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	$ 50

[1] No credit arrangements expire in 2017.