Retirement Benefits (Tables)

9 Months Ended

Sep. 30, 2011

Retirement Benefits [Abstract]

Pension Plans and Postretirement Plans

	Southern			Alabama			Georgia			Gulf			Mississippi
Pension Plans	Company			Power			Power			Power			Power
	(in millions)
Three Months Ended September 30, 2011
Service cost	$	46		$	11		$	14		$	2		$	3
Interest cost		97			24			36			4			4
Expected return on plan assets		(152	)		(44	)		(59	)		(6	)		(7	)
Net amortization		14			3			5			—			1
Net cost (income)	$	5		$	(6	)	$	(4	)	$	—		$	1
Nine Months Ended September 30, 2011
Service cost	$	138		$	32		$	43		$	6		$	7
Interest cost		292			72			108			13			13
Expected return on plan assets		(456	)		(130	)		(176	)		(20	)		(19	)
Net amortization		40			10			14			1			2
Net cost (income)	$	14		$	(16	)	$	(11	)	$	—		$	3
Three Months Ended September 30, 2010
Service cost	$	43		$	10		$	13		$	2		$	2
Interest cost		98			25			36			5			4
Expected return on plan assets		(138	)		(42	)		(54	)		(6	)		(5	)
Net amortization		11			3			4			—			1
Net cost (income)	$	14		$	(4	)	$	(1	)	$	1		$	2
Nine Months Ended September 30, 2010
Service cost	$	129		$	31		$	40		$	6		$	6
Interest cost		293			73			109			13			13
Expected return on plan assets		(413	)		(126	)		(164	)		(18	)		(16	)
Net amortization		32			8			11			1			2
Net cost (income)	$	41		$	(14	)	$	(4	)	$	2		$	5

	Southern			Alabama			Georgia			Gulf			Mississippi
Postretirement Benefits	Company			Power			Power			Power			Power
	(in millions)
Three Months Ended September 30, 2011
Service cost	$	6		$	1		$	1		$	—		$	—
Interest cost		23			6			11			1			1
Expected return on plan assets		(16	)		(6	)		(8	)		—			—
Net amortization		5			2			3			—			—
Net cost (income)	$	18		$	3		$	7		$	1		$	1
Nine Months Ended September 30, 2011
Service cost	$	16		$	4		$	5		$	1		$	1
Interest cost		69			18			31			3			3
Expected return on plan assets		(48	)		(19	)		(23	)		(1	)		(1	)
Net amortization		15			5			8			—			—
Net cost (income)	$	52		$	8		$	21		$	3		$	3
Three Months Ended September 30, 2010
Service cost	$	6		$	2		$	3		$	—		$	—
Interest cost		25			7			11			1			2
Expected return on plan assets		(15	)		(7	)		(8	)		—			—
Net amortization		5			2			2			—			—
Net cost (income)	$	21		$	4		$	8		$	1		$	2
Nine Months Ended September 30, 2010
Service cost	$	19		$	5		$	7		$	1		$	1
Interest cost		75			20			33			3			4
Expected return on plan assets		(47	)		(19	)		(23	)		(1	)		(1	)
Net amortization		15			5			8			—			—
Net cost (income)	$	62		$	11		$	25		$	3		$	4