Summary of Significant Accounting Policies (Details 6) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Oct. 20, 2011
Summary of Significant Accounting Policies (Textual) [Abstract]
Other cost of removal obligations, amortization period	over the remaining two-year period
Investment securities in the Funds	$ 1,207,000,000	$ 1,370,000,000
Increase (Decrease) in fair value of securities related to nuclear decommissioning	29,000,000	139,000,000	215,000,000
Non-cash property additions recognized	929,000,000	427,000,000	370,000,000
Amount of Facility reflected in Southern Company and Mississippi Power financial statements	431,000,000
Summary of Significant Accounting Policies Additional (Textual) [Abstract]
Amortization period of other cost of removal obligations	2 years
Related property lives in years	which may range up to 65 years
Life of new issue in years	which may range up to 50 years
Recovery and amortization periods for regulatory assets (liabilities), approved by PSCs	Periods not exceeding 5 years
Life of the new issue	range up to 50 years
Recovered and amortized as approved by the appropriate state PSCs	periods not exceeding 14 years
Recovery and amortization periods for regulatory assets (liabilities), average remaining service period	up to 15 years
Maximum revenue from a single customer or industry	10.00%
Maximum percentage of uncollectible accounts	1.00%
Amortization of deferred investment tax credits	19,000,000	23,000,000	24,000,000
Credits amortized to income tax expense	900,000
Reduction in Tax Basis of Assets	50.00%
Depreciation of cost of utility plant in service, composite straight-line rate	3.20%	3.30%	3.20%
Accumulated depreciation for utility plant in service, total	20,700,000,000	19,700,000,000
Depreciation of the original cost of other plant in service, minimum useful live	3 years
Depreciation of the original cost of other plant in service, maximum useful live	25 years
Accumulated depreciation for other plant in service, total	456,000,000	441,000,000
Minimum net worth requirement by a one or more persons to hold external trust funds	100,000,000
Proceeds from sale of securities held in external trust funds	2,200,000,000	2,000,000,000	1,200,000,000
AFUDC and interest capitalized, net of income taxes	9.10%	12.50%	15.30%
Cash payments for interest totaled	832,000,000	789,000,000	788,000,000
Net of amounts capitalized	78,000,000	86,000,000	84,000,000
Several leveraged lease agreements, which relate to international and domestic energy with terms ranging	up to 45 years
Loss on the terminations of leveraged lease investments			17,000,000
Terminated international leveraged lease investments			2
Gain on the termination of leveraged lease investments			26,000,000
Original maturities of temporary cash investments	90 days or less
Impairment loss on leverage leases after tax	90,000,000
Maximum [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Life of related property over which deferred income tax liabilities are amortized	65 years
New issue life in years	50 years
Regulatory assets liabilities approved by public service commission	5 years
Recovered and amortization periods as approved by appropriate state public service commission	14 years
Recovery and amortization period for regulatory assets liabilities average remaining service period	15 years
Plant Hatch [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Estimated cost of decommissioning used in current rates	584,000,000
Amount expensed for rate making purpose	2,000,000
Plant Vogtle [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Estimated cost of decommissioning used in current rates	426,000,000
Amount expensed for rate making purpose		3,000,000	3,000,000
Alabama Power [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Refueling cycles for Alabama Power and Georgia Power, minimum months	18 months
Refueling cycles for Alabama Power and Georgia Power, maximum months	24 months
Investment securities in the Funds	540,000,000	552,000,000
Significant assumption of inflation rate used to determine the costs for rate making	4.50%
Significant assumption of trust earnings rate used to determine the costs for rate making	7.00%
Additional accrued reserve to cover the cost of damages totaled for Alabama Power, Gulf Power, and Mississippi Power	31,000,000	48,000,000
Summary of Significant Accounting Policies Additional (Textual) [Abstract]
Cash payments for interest totaled	286,000,000	288,000,000	255,000,000
Net of amounts capitalized	9,000,000	14,000,000	33,000,000
Georgia Power [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Other cost of removal obligations related to Georgia Power	62,000,000
Regulatory liability for state income tax credits amortization period	21 months
Refueling cycles for Alabama Power and Georgia Power, minimum months	18 months
Refueling cycles for Alabama Power and Georgia Power, maximum months	24 months
Investment securities in the Funds	667,000,000	818,000,000
Significant assumption of inflation rate used to determine the costs for rate making	2.40%
Significant assumption of trust earnings rate used to determine the costs for rate making	4.40%
Regulatory liabilities amortized	31,000,000
Fair market value of fund's securities on loan under the Funds' managers' securities lending program	39,000,000	141,000,000
Fair value of collateral received	42,000,000	144,000,000
Lesser obligation related to aggregate principal amount	250,000,000
Summary of Significant Accounting Policies Additional (Textual) [Abstract]
Cash payments for interest totaled	346,000,000	339,000,000	341,000,000
Net of amounts capitalized	37,000,000	54,000,000	40,000,000
Georgia Power [Member] | Plant McIntosh [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Amortization period of defer costs of certain significant inspection costs for the combustion turbines	over 10 years
Amortization period of defer inspection costs for the combustion turbines	10 years
Mississippi Power [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Cash payment to be made in conjunction with purchase of facility				85,000,000
Lesser obligation related to aggregate principal amount	240,000,000			270,000,000
Fixed stated interest rate of debt obligation				7.13%
Fair value of debt assumed in Plant Daniel Combined Cycle Generating Units				346,000,000
Summary of Significant Accounting Policies Additional (Textual) [Abstract]
Cash payments for interest totaled	14,814,000	19,518,000	19,832,000
Net of amounts capitalized	10,065,000	2,903,000	117,000
Traditional Operating Companies [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Accrued reserve to cover the cost of damages for traditional operating companies	29,000,000	32,000,000
Equity Securities [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Investment securities in the Funds	626,000,000	664,000,000
Debt Securities [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Investment securities in the Funds	543,000,000	632,000,000
Other Securities [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Investment securities in the Funds	36,000,000	74,000,000
Securities Held in Funds [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Increase (Decrease) in fair value of securities related to nuclear decommissioning		6,000,000	198,000,000
Securities Held in Funds [Member] | Realized gain [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Increase (Decrease) in fair value of securities related to nuclear decommissioning	41,000,000
Securities Held in Funds [Member] | Unrealized Losses [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]
Increase (Decrease) in fair value of securities related to nuclear decommissioning	$ 60,000,000