Retirement Benefits - Actuarial Assumptions 1 (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Discount rate:
Annual salary increase	3.59%	3.84%	3.84%	4.18%
Pension Plans [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.26%	4.98%	5.52%	5.93%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.20%	8.45%	8.45%
Other Postretirement Benefits [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.05%	4.88%	5.40%	5.83%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	7.29%	7.39%	7.40%
Gulf Power [Member]
Discount rate:
Annual salary increase	3.59%	3.84%	3.84%	4.18%
Gulf Power [Member] | Pension Plans [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.27%	4.98%	5.53%	5.93%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.20%	8.45%	8.45%
Gulf Power [Member] | Other Postretirement Benefits [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.06%	4.88%	5.41%	5.84%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.02%	8.11%	8.18%
Georgia Power [Member]
Discount rate:
Annual salary increase	3.59%	3.84%	3.84%	4.18%
Georgia Power [Member] | Pension Plans [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.27%	4.98%	5.52%	5.93%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.20%	8.45%	8.45%
Georgia Power [Member] | Other Postretirement Benefits [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.04%	4.87%	5.40%	5.83%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	7.24%	7.25%	7.24%
Alabama Power [Member]
Discount rate:
Annual salary increase	3.59%	3.84%	3.84%	4.18%
Alabama Power [Member] | Pension Plans [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.27%	4.98%	5.52%	5.93%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.20%	8.45%	8.45%
Alabama Power [Member] | Other Postretirement Benefits [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.06%	4.88%	5.41%	5.84%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	7.19%	7.39%	7.43%
Mississippi Power [Member]
Discount rate:
Annual salary increase	3.59%	3.84%	3.84%	4.18%
Mississippi Power [Member] | Pension Plans [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.26%	4.98%	5.51%	5.92%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	8.20%	8.45%	8.45%
Mississippi Power [Member] | Other Postretirement Benefits [Member]
Discount rate:
Discount rate on net periodic benefit costs	4.04%	4.87%	5.39%	5.83%
Long-term return on plan assets:
Long-term return on plan assets on net periodic benefit costs	6.96%	7.53%	7.65%