CONSOLIDATED STATEMENTS OF CAPITALIZATION (Parenthetical)	Dec. 31, 2011
Long-term debt:
Notes payable, Interest Rate, Percentage (as a percent)	1.53%
Federal Financing Bank | Mortgage notes payable to the Federal Financing Bank at interest rates varying from 2.70% to 8.43% (average rate of 5.01% at December 31, 2011) due in quarterly installments through 2043
Long-term debt:
Debt Instrument, Interest Rate Minimum (as a percent)	2.70%
Debt Instrument, Interest Rate Maximum (as a percent)	8.43%
Debt Instrument, Interest Rate Average (as a percent)	5.01%
National Rural Utilities Cooperative Finance Corporation | Mortgage notes payable to National Rural Utilities Cooperative Finance Corporation at interest rates varying from 3.00% to 4.90% (average rate of 4.07% at December 31, 2011) due in quarterly installments through 2020
Long-term debt:
Debt Instrument, Interest Rate Minimum (as a percent)	3.00%
Debt Instrument, Interest Rate Maximum (as a percent)	4.90%
Debt Instrument, Interest Rate Average (as a percent)	4.07%
Public | Mortgage bonds payable: Series 2006 Term Bonds, 5.534%, due 2031 through 2035
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	5.534%
Public | Mortgage bonds payable: Series 2007 Term Bonds, 6.191%, due 2024 through 2031
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	6.191%
Public | Mortgage bonds payable: Series 2009A Term Bonds, 6.10%, due 2019
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	6.10%
Public | Mortgage bonds payable: Series 2009B Term Bonds, 5.95%, due 2039
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	5.95%
Public | Mortgage bonds payable: Series 2009 Clean renewable energy bond, 1.81%, due 2024
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	1.81%
Public | Mortgage bonds payable: Series 2010A Term bonds, 5.375% due 2040
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	5.375%
Public | Mortagage bonds payable: Series 2011A Term bonds, 5.25% due 2050
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	5.25%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 1992A Monroe, Serial bonds, 6.80%, due through 2012
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	6.80%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2003A Burke, Heard, Monroe and 2003B Burke Auction rate bonds, 0.44%, due 2024
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	0.44%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2004 Burke and Monroe Auction rate bonds, 0.41%, due 2020
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	0.41%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2005 Burke and Monroe Auction rate bonds, 0.44%, due 2040
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	0.44%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2008A through C Burke Fixed rate bonds, 5.30% to 5.70%, due 2032 through 2043
Long-term debt:
Debt Instrument, Interest Rate Minimum (as a percent)	5.30%
Debt Instrument, Interest Rate Maximum (as a percent)	5.70%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2008E Burke Fixed rate bonds, 7.00%, due 2020 through 2023
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	7.00%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2008G Burke Term rate bonds, 6.75% through March 31, 2012, due 2039
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	6.75%
Georgia Development Authorities | Mortgage notes issued in connection with the sale of pollution control revenue bonds: Series 2009A Heard and Monroe, and 2009B Monroe Weekly rate bonds, 0.07% to 0.08%, due 2030 through 2038
Long-term debt:
Debt Instrument, Interest Rate Minimum (as a percent)	0.07%
Debt Instrument, Interest Rate Maximum (as a percent)	0.08%
Georgia Development Authorities | Mortgage notes issued Series 2010A Burke and Monroe, and 2010B Burke Weekly rate bonds, 0.12%, due 2036 through 2037
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	0.12%
Georgia Development Authorities | Mortgage notes issued Series 2011A Burke and Monroe, and 2010B Burke Weekly rate bonds, 0.12%, due 2036 through 2037
Long-term debt:
Debt Instrument, Interest Rate, Stated Percentage (as a percent)	0.12%
CoBank | ACB notes payable: Transmission mortgage note payable: variable at an average rate of 2.19% through January 29, 2012, due in bimonthly installments through November 1, 2018
Long-term debt:
Debt Instrument, Interest Rate Average (as a percent)	2.19%
CoBank | ACB notes payable: Transmission mortgage note payable: variable at an average rate of 2.18% through January 29, 2012, due in bimonthly installments through September 1, 2019
Long-term debt:
Debt Instrument, Interest Rate Average (as a percent)	2.18%