Financing (DetailsTextual) (USD $)	1 Months Ended	12 Months Ended
	Oct. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Oct. 20, 2011
Financing (Textual) [Abstract]
Ratio of indebtedness to capitalization covenant		65.00%
Senior Notes outstanding		$ 15,900,000,000	$ 15,200,000,000
Unused		5,137,000,000
Proceeds from issuance of junior subordinated notes		206,000,000	412,000,000
Purchased Plant		4,525,000,000	4,086,000,000	4,670,000,000
Financing (Additional Textual) [Abstract]
Long term debt maturities in 2012		1,700,000,000
Long term debt maturities in 2013		2,100,000,000
Long term debt maturities in 2014		449,000,000
Long term debt maturities in 2015		1,200,000,000
Long term debt maturities in 2016		1,200,000,000
Average commitment fees		1/4 of 1% or less
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support		1,800,000,000
Senior Notes [Member]
Financing (Textual) [Abstract]
Issuance of senior notes		2,800,000,000
Secured Debt [Member]
Financing (Textual) [Abstract]
Pollution control revenue bonds, outstanding		194,000,000
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Financing (Textual) [Abstract]
Preferred securities, outstanding		200,000,000	400,000,000
Series 2007A [Member]
Financing (Textual) [Abstract]
Maturities of Senior notes		500,000,000
Fixed stated interest rate of debt obligation		5.30%
Southern Company [Member]
Financing (Textual) [Abstract]
Senior Notes outstanding		1,800,000,000	1,600,000,000
Unused		1,000,000,000
Southern Company [Member] | Senior Notes [Member]
Financing (Textual) [Abstract]
Issuance of senior notes		500,000,000
Alabama Power [Member]
Financing (Textual) [Abstract]
Redemption amount of principal		1,000,000
Unused		1,306,000,000
Purchased Plant		977,000,000	903,000,000	1,234,000,000
Alabama Power [Member] | Series 2012A [Member]
Financing (Textual) [Abstract]
Issuance of senior notes		250,000,000
Fixed stated interest rate of debt obligation		4.10%
Alabama Power [Member] | Series 2007B [Member]
Financing (Textual) [Abstract]
Redemption amount of principal notes		250,000,000
Fixed stated interest rate of debt obligation		5.875%
Georgia Power [Member]
Financing (Textual) [Abstract]
Bank six-month term loan agreement principal amount		200,000,000
Bank term loans outstanding		690,000,000
Ratio of indebtedness to capitalization covenant		65.00%
Aggregate principal amount of floating rate bank loan		100,000,000
Issuance of senior notes		250,000,000
Unused		1,745,000,000
Proceeds from issuance of junior subordinated notes		0	206,000,000
Purchased Plant		1,861,000,000	2,190,000,000	2,515,000,000
Southern Power [Member]
Financing (Textual) [Abstract]
Unused		500,000,000
Purchased Plant		254,725,000	299,602,000	137,133,000
Mississippi Power [Member]
Financing (Textual) [Abstract]
Bank term loans outstanding			615,000,000
Ratio of indebtedness to capitalization covenant		65.00%
Issuance of senior notes		240,000,000			270,000,000
Fixed stated interest rate of debt obligation					7.13%
Other revenue bond obligation		50,000,000	100,000,000
Amount of principal obligation assumed under Lease	270,000,000
Unused		296,000,000
Purchased Plant		964,233,000	247,005,000	101,995,000
Revenue Bond Obligations Face Value	270,000,000
Revenue Bond Obligations Fair Value	346,000,000
Mississippi Power [Member] | Plant Daniel Units 3 and 4 [Member]
Financing (Textual) [Abstract]
Purchased Plant	85,000,000
Mississippi Power [Member] | Revenue Bonds [Member]
Financing (Textual) [Abstract]
Fixed interest rate on revenue bond	7.13%
Traditional Operating Companies [Member]
Financing (Textual) [Abstract]
Pollution control revenue bonds, outstanding		3,400,000,000	3,100,000,000
Traditional Operating Companies [Member] | Senior Notes [Member]
Financing (Textual) [Abstract]
Issuance of senior notes		$ 2,300,000,000