Consolidated Statements of Capitalization (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Common stock, Par value	$ 5	$ 5
Common stock, shares authorized	1,500,000,000	1,500,000,000
Common stock, shares issued	878,000,000	866,000,000
Treasury shares	10,000,000	500,000
Annual interest requirement	$ 821.0
Annual dividend requirement	45.0
Redeemable Preferred Stock, $1 par value
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Redeemable Cumulative preferred stock, Authorized	28,000,000	28,000,000
Redeemable Cumulative preferred stock, Outstanding	12,000,000	12,000,000
Redeemable Preferred Stock, $1 par value | Cumulative Preferred Stock
Dividend Rate, Minimum	5.20%	5.20%
Dividend Rate, Maximum	5.83%	5.83%
Redeemable Preferred Stock, $100 par or stated value
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Redeemable Cumulative preferred stock, Authorized	20,000,000	20,000,000
Redeemable Cumulative preferred stock, Outstanding	1,000,000	1,000,000
Redeemable Preferred Stock, $100 par or stated value | Cumulative Preferred Stock
Dividend Rate, Minimum	4.20%	4.20%
Dividend Rate, Maximum	5.44%	5.44%
Redeemable Preferred Stock, $25 stated value
Preferred Stock, Par or Stated Value Per Share	$ 25	$ 25
Preference Stock , $100 par or stated value
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Preference stock, Outstanding	3,000,000	3,000,000
Dividend Rate, Minimum	6.00%	6.00%
Dividend Rate, Maximum	6.50%	6.50%
Preference Stock, $1 par value
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Preference stock, Authorized	65,000,000	65,000,000
Preference stock, Outstanding	14,000,000	14,000,000
Dividend Rate, Minimum	5.63%	5.63%
Dividend Rate, Maximum	6.50%	6.50%
Redeemable Preferred Stock of Subsidiaries
Annual dividend requirement	20.0
Noncumulative Preferred Stock
Preferred Stock, Par or Stated Value Per Share	$ 25	$ 25
Preference stock, Authorized	60,000,000	60,000,000
Preference stock, Outstanding	2,000,000	2,000,000
Dividend Rate, Minimum	6.00%	6.00%
Dividend Rate, Maximum	6.13%	6.13%
2011
Interest Rates, Minimum	4.85%	4.85%
Interest Rates, Maximum	5.30%	5.30%
Maturity of Long Term Senior Notes and Debt in Year Five [Member]
Interest Rates, Minimum	1.95%	1.95%
Interest Rates, Maximum	5.30%	5.30%
Maturity of Long Term Senior Notes and Debt in Year Six [Member]
Interest Rates, Minimum	5.50%	5.50%
Interest Rates, Maximum	5.90%	5.90%
Variable rate, Due 2016
Fixed stated interest rate of debt obligation	0.17%
Maturity Of Pollution Control Bonds Variable Rate Due Two Thousand Fifteen Member
Fixed stated interest rate of debt obligation	0.13%
Maturity of Taxable Revenue Bonds Period One [Member]
Fixed stated interest rate of debt obligation	7.13%	7.13%
Variable rate due 2042
Fixed stated interest rate of debt obligation	3.41%
Maturity of Pollution Control Bonds Period Two [Member]
Interest Rates, Minimum	0.08%
Interest Rates, Maximum	0.24%
Maturity of Pollution Control Bonds Period One [Member]
Interest Rates, Minimum	0.55%	0.55%
Interest Rates, Maximum	6.00%	6.00%
Maturity of Long Term Senior Notes and Debt After Year Six [Member]
Interest Rates, Minimum	2.25%	2.25%
Interest Rates, Maximum	8.20%	8.20%
Maturity of Pollution Control Bonds Period Three [Member]
Interest Rates, Minimum	0.13%
Interest Rates, Maximum	0.17%
Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Interest Rates, Minimum	1.30%	1.30%
Interest Rates, Maximum	6.00%	6.00%
Maturity of Long Term Senior Notes and Debt in Year Three [Member]
Interest Rates, Minimum	4.15%	4.15%
Interest Rates, Maximum	4.90%	4.90%
Maturity of Long Term Senior Notes and Debt in Year Four [Member]
Interest Rates, Minimum	0.55%	0.55%
Interest Rates, Maximum	5.25%	5.25%
Adjustable Rate Loans [Member] | 2011
Interest Rates, Minimum		0.60%
Interest Rates, Maximum		0.95%
Adjustable Rate Loans [Member] | Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Interest Rates, Minimum	0.58%
Interest Rates, Maximum	1.21%
Alabama Power [Member]
Common stock, Par value	$ 40	$ 40
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares outstanding	30,537,500	30,537,500
Annual interest requirement	250.0
Annual dividend requirement	21.0
Alabama Power [Member] | Redeemable Preferred Stock, $1 par value
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Redeemable Cumulative preferred stock, Authorized	27,500,000	27,500,000
Redeemable Cumulative preferred stock, Outstanding	12,000,000	12,000,000
Dividend Rate, Minimum	5.20%	5.20%
Dividend Rate, Maximum	5.83%	5.83%
Alabama Power [Member] | Redeemable Preferred Stock, $100 par or stated value
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Redeemable Cumulative preferred stock, Authorized	3,850,000	3,850,000
Redeemable Cumulative preferred stock, Outstanding	475,115	475,115
Alabama Power [Member] | Redeemable Preferred Stock, $100 par or stated value | Cumulative Preferred Stock
Dividend Rate, Minimum	4.20%	4.20%
Dividend Rate, Maximum	4.92%	4.92%
Alabama Power [Member] | Redeemable Preferred Stock, $25 stated value
Preferred Stock, Par or Stated Value Per Share	$ 25	$ 25
Alabama Power [Member] | Preference Stock, $1 par value
Preferred Stock, Par or Stated Value Per Share	$ 1	$ 1
Dividend Rate, Minimum	5.63%	5.63%
Dividend Rate, Maximum	6.50%	6.50%
Alabama Power [Member] | Redeemable Preferred Stock of Subsidiaries
Annual dividend requirement	18.0
Alabama Power [Member] | Noncumulative Preferred Stock
Preferred Stock, Par or Stated Value Per Share	$ 25	$ 25
Preference stock, Authorized	40,000,000	40,000,000
Preference stock, Outstanding	14,000,000	14,000,000
Alabama Power [Member] | 2011
Fixed stated interest rate of debt obligation	4.85%	4.85%
Alabama Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Five [Member]
Fixed stated interest rate of debt obligation	5.20%	5.20%
Alabama Power [Member] | Maturity of Long Term Senior Notes And Debt Two Thousand Seventeen [Member]
Interest Rates, Minimum	5.50%	5.50%
Interest Rates, Maximum	5.55%	5.55%
Alabama Power [Member] | Maturity of Long Term Senior Notes And Debt Two Thousand Nineteen To Two Thousand Forty Seven [Member]
Interest Rates, Minimum	3.375%	3.375%
Interest Rates, Maximum	6.125%	6.125%
Alabama Power [Member] | Maturity of Pollution Control Bonds Two Thousand Thirty Four [Member]
Interest Rates, Minimum	0.58%	0.58%
Interest Rates, Maximum	5.00%	5.00%
Alabama Power [Member] | Maturity Of Pollution Control Bonds Variable Rate Two Thousand Twenty One To Two Thousand Thirty Eight [Member]
Interest Rates, Minimum	0.08%
Interest Rates, Maximum	0.20%
Alabama Power [Member] | Variable rate, Due 2015
Fixed stated interest rate of debt obligation	0.13%
Alabama Power [Member] | Maturity Of Pollution Control Bonds Two Thousand Seventeen [Member]
Interest Rates, Minimum	0.13%
Interest Rates, Maximum	0.17%
Alabama Power [Member] | Variable rate due 2042
Fixed stated interest rate of debt obligation	3.41%
Alabama Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Fixed stated interest rate of debt obligation	5.80%	5.80%
Alabama Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Four [Member]
Fixed stated interest rate of debt obligation	0.55%	0.55%
Georgia Power [Member]
Fixed stated interest rate of debt obligation	7.90%	7.40%
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares outstanding	9,261,500	9,261,500
Annual interest requirement	338.0
Annual dividend requirement	17.0
Georgia Power [Member] | Noncumulative Preferred Stock, $25 par value
Preferred Stock, Par or Stated Value Per Share	$ 25	$ 25
Preference stock, Authorized	50,000,000	50,000,000
Preference stock, Outstanding	1,800,000	1,800,000
Dividend Rate	6.125%	6.125%
Georgia Power [Member] | Noncumulative Preferred Stock, $100 par value
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Preference stock, Authorized	15,000,000	15,000,000
Preference stock, Outstanding	2,250,000	2,250,000
Dividend Rate	6.50%	6.50%
Georgia Power [Member] | 2011
Fixed stated interest rate of debt obligation	5.125%	5.125%
Georgia Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Five [Member]
Fixed stated interest rate of debt obligation	3.00%	3.00%
Georgia Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Six [Member]
Fixed stated interest rate of debt obligation	5.70%	5.70%
Georgia Power [Member] | Maturity of Long Term Senior Notes and Debt Two Thousand Eighteen to Two Thousand Forty Eight [Member]
Interest Rates, Minimum	2.85%	2.85%
Interest Rates, Maximum	8.20%	8.20%
Georgia Power [Member] | Variable rate, Due 2016
Fixed stated interest rate of debt obligation	0.17%
Georgia Power [Member] | 2022 - 2049
Interest Rates, Minimum	0.80%	0.80%
Interest Rates, Maximum	5.75%	5.75%
Georgia Power [Member] | Variable rate, due 2013
Interest Rates, Minimum	0.58%
Interest Rates, Maximum	0.63%
Georgia Power [Member] | Variable rate, Due 2012
Interest Rates, Minimum	0.85%
Interest Rates, Maximum	0.95%
Georgia Power [Member] | Variable rate, Due 2018-2052
Interest Rates, Minimum	0.12%
Interest Rates, Maximum	0.24%
Georgia Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Interest Rates, Minimum	1.30%	1.30%
Interest Rates, Maximum	6.00%	6.00%
Georgia Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Four [Member]
Interest Rates, Minimum	0.625%	0.625%
Interest Rates, Maximum	5.25%	5.25%
Gulf Power [Member]
Preference stock, Authorized	20,000,000	20,000,000
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares outstanding	4,542,717	4,142,717
Annual interest requirement	55.1
Annual dividend requirement	6.2
Gulf Power [Member] | Preference Stock , $100 par or stated value
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Preference stock, Authorized	10,000,000	10,000,000
Preference stock, Outstanding	1,000,000	1,000,000
Gulf Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Five [Member]
Fixed stated interest rate of debt obligation	5.30%	5.30%
Gulf Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Six [Member]
Fixed stated interest rate of debt obligation	5.90%	5.90%
Gulf Power [Member] | 2020-2051
Interest Rates, Minimum	3.10%	3.10%
Interest Rates, Maximum	5.75%	5.75%
Gulf Power [Member] | 2022 - 2049
Interest Rates, Minimum	0.55%	0.55%
Interest Rates, Maximum	6.00%	6.00%
Gulf Power [Member] | Variable Rate, Due 2022-2039
Interest Rates, Minimum	0.13%
Interest Rates, Maximum	0.17%
Gulf Power [Member] | 6.0% preference stock | Preference Stock , $100 par or stated value
Fixed stated interest rate of debt obligation	6.00%	6.00%
Gulf Power [Member] | 6.45% preference stock | Preference Stock , $100 par or stated value
Fixed stated interest rate of debt obligation	6.45%	6.45%
Gulf Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Fixed stated interest rate of debt obligation	4.35%	4.35%
Gulf Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Three [Member]
Fixed stated interest rate of debt obligation	4.90%	4.90%
Mississippi Power [Member]
Fixed stated interest rate of debt obligation	9.967%
Preferred Stock, Par or Stated Value Per Share	$ 100	$ 100
Redeemable Cumulative preferred stock, Authorized	1,244,139	1,244,139
Redeemable Cumulative preferred stock, Outstanding	334,210	334,210
Common stock, shares authorized	1,130,000	1,130,000
Common stock, shares outstanding	1,121,000	1,121,000
Annual interest requirement	71.3
Annual dividend requirement	$ 1.7
Dividend Rate, Minimum	4.40%	4.40%
Dividend Rate, Maximum	5.25%	5.25%
Mississippi Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Five [Member]
Fixed stated interest rate of debt obligation	2.35%	2.35%
Mississippi Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Six [Member]
Fixed stated interest rate of debt obligation	5.60%	5.60%
Mississippi Power [Member] | Maturity of Long Term Senior Notes and Debt Two Thousand Nineteen to Two Thousand Forty Two [Member]
Interest Rates, Minimum	2.25%	2.25%
Interest Rates, Maximum	5.63%	5.63%
Mississippi Power [Member] | 2028
Fixed stated interest rate of debt obligation	5.15%	5.15%
Mississippi Power [Member] | Variable Rate, Due 2020-2028
Interest Rates, Minimum	0.12%
Interest Rates, Maximum	0.14%
Mississippi Power [Member] | Maturity of Taxable Revenue Bonds Period One [Member]
Fixed stated interest rate of debt obligation	7.13%	7.13%
Mississippi Power [Member] | Variable rate, due 2013
Interest Rates, Minimum	0.63%
Interest Rates, Maximum	1.21%
Mississippi Power [Member] | Variable rate, Due 2012
Interest Rates, Minimum		0.60%
Interest Rates, Maximum		0.85%
Mississippi Power [Member] | Maturity of Long Term Senior Notes and Debt in Year Two [Member]
Fixed stated interest rate of debt obligation	6.00%	6.00%