Retirement Benefits (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Alabama Power [Member] | Pension Plans [Member]
Pension Plans and Postretirement Plans
Service cost	$ 11	$ 10	$ 32	$ 31
Interest cost	24	25	72	73
Expected return on plan assets	(44)	(42)	(130)	(126)
Net amortization	3	3	10	8
Net cost (income)	(6)	(4)	(16)	(14)
Alabama Power [Member] | Postretirement Benefits [Member]
Pension Plans and Postretirement Plans
Service cost	1	2	4	5
Interest cost	6	7	18	20
Expected return on plan assets	(6)	(7)	(19)	(19)
Net amortization	2	2	5	5
Net cost (income)	3	4	8	11
Georgia Power [Member] | Pension Plans [Member]
Pension Plans and Postretirement Plans
Service cost	14	13	43	40
Interest cost	36	36	108	109
Expected return on plan assets	(59)	(54)	(176)	(164)
Net amortization	5	4	14	11
Net cost (income)	(4)	(1)	(11)	(4)
Georgia Power [Member] | Postretirement Benefits [Member]
Pension Plans and Postretirement Plans
Service cost	1	3	5	7
Interest cost	11	11	31	33
Expected return on plan assets	(8)	(8)	(23)	(23)
Net amortization	3	2	8	8
Net cost (income)	7	8	21	25
Gulf Power [Member] | Pension Plans [Member]
Pension Plans and Postretirement Plans
Service cost	2	2	6	6
Interest cost	4	5	13	13
Expected return on plan assets	(6)	(6)	(20)	(18)
Net amortization			1	1
Net cost (income)		1		2
Gulf Power [Member] | Postretirement Benefits [Member]
Pension Plans and Postretirement Plans
Service cost			1	1
Interest cost	1	1	3	3
Expected return on plan assets			(1)	(1)
Net cost (income)	1	1	3	3
Mississippi Power [Member] | Pension Plans [Member]
Pension Plans and Postretirement Plans
Service cost	3	2	7	6
Interest cost	4	4	13	13
Expected return on plan assets	(7)	(5)	(19)	(16)
Net amortization	1	1	2	2
Net cost (income)	1	2	3	5
Mississippi Power [Member] | Postretirement Benefits [Member]
Pension Plans and Postretirement Plans
Service cost			1	1
Interest cost	1	2	3	4
Expected return on plan assets			(1)	(1)
Net cost (income)	1	2	3	4
Pension Plans [Member]
Pension Plans and Postretirement Plans
Service cost	46	43	138	129
Interest cost	97	98	292	293
Expected return on plan assets	(152)	(138)	(456)	(413)
Net amortization	14	11	40	32
Net cost (income)	5	14	14	41
Postretirement Benefits [Member]
Pension Plans and Postretirement Plans
Service cost	6	6	16	19
Interest cost	23	25	69	75
Expected return on plan assets	(16)	(15)	(48)	(47)
Net amortization	5	5	15	15
Net cost (income)	$ 18	$ 21	$ 52	$ 62