Common Stock and Stock Compensation - Stock Options, Assumptions Used (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	17.70%	17.50%	17.40%
Expected term (in years)	5 years	5 years	5 years
Interest rate	0.90%	2.30%	2.40%
Dividend yield, percentage	4.20%	4.80%	5.60%
Weighted average grant-date fair value	$ 3.39	$ 3.23	$ 2.23
Georgia Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	17.70%	17.50%	17.40%
Expected term (in years)	5 years	5 years	5 years
Interest rate	0.90%	2.30%	2.40%
Dividend yield, percentage	4.20%	4.80%	5.60%
Weighted average grant-date fair value	3.39	3.23	2.23
Alabama Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	17.70%	17.50%	17.40%
Expected term (in years)	5 years	5 years	5 years
Interest rate	0.90%	2.30%	2.40%
Dividend yield, percentage	4.20%	4.80%	5.60%
Weighted average grant-date fair value	3.39	3.23	2.23
Gulf Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	17.70%	17.50%	17.40%
Expected term (in years)	5 years	5 years	5 years
Interest rate	0.90%	2.30%	2.40%
Dividend yield, percentage	4.20%	4.80%	5.60%
Weighted average grant-date fair value	3.39	3.23	2.23
Performance Share Plan [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	16.00%	19.20%	20.70%
Expected term (in years)	3 years	3 years	3 years
Interest rate	0.40%	1.40%	1.40%
Dividend yield	$ 1.89	$ 1.82	$ 1.75
Weighted average grant-date fair value	41.99	35.97	30.13
Performance Share Plan [Member] | Mississippi Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	16.00%	19.20%	20.70%
Expected term (in years)	3 years	3 years	3 years
Interest rate	0.40%	1.40%	1.40%
Dividend yield	$ 1.89	$ 1.82	$ 1.75
Weighted average grant-date fair value	41.99	35.97	30.13
Performance Share Plan [Member] | Georgia Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	16.00%	19.20%	20.70%
Expected term (in years)	3 years	3 years	3 years
Interest rate	0.40%	1.40%	1.40%
Dividend yield	$ 1.89	$ 1.82	$ 1.75
Weighted average grant-date fair value	41.99	35.97	30.13
Performance Share Plan [Member] | Alabama Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	16.00%	19.20%	20.70%
Expected term (in years)	3 years	3 years	3 years
Interest rate	0.40%	1.40%	1.40%
Dividend yield	$ 1.89	$ 1.82	$ 1.75
Weighted average grant-date fair value	41.99	35.97	30.13
Performance Share Plan [Member] | Gulf Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	16.00%	19.20%	20.70%
Expected term (in years)	3 years	3 years	3 years
Interest rate	0.40%	1.40%	1.40%
Dividend yield	$ 1.89	$ 1.82	$ 1.75
Weighted average grant-date fair value	41.99	35.97	30.13
Stock Options [Member] | Mississippi Power [Member]
Assumptions used in the pricing model and the weighted average grant-date fair value of stock options granted
Expected volatility	17.70%	17.50%	17.40%
Expected term (in years)	5 years	5 years	5 years
Interest rate	0.90%	2.30%	2.40%
Dividend yield, percentage	4.20%	4.80%	5.60%
Weighted average grant-date fair value	$ 3.39	$ 3.23	$ 2.23