Leaseback Obligations	12 Months Ended
Sep. 30, 2011
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Leaseback Obligations	Leaseback Obligations Prior to 2004, TVA received approximately $945 million in proceeds by entering into leaseback transactions for 24 new peaking combustion turbine units. TVA also received approximately $389 million in proceeds by entering into a leaseback transaction for qualified technological equipment and software in 2003. Due to TVA’s continuing involvement in the operation and maintenance of the leased units and equipment and its control over the distribution of power produced by the combustion turbine facilities during the leaseback term, TVA accounted for the lease proceeds of $1.3 billion as financing obligations. The outstanding leaseback obligations on TVA's balance sheets were approximately $885 million at September 30, 2011, and $940 million at September 30, 2010. Seven States Power Corporation ("Seven States"), through its subsidiary, Seven States Southaven, LLC ("SSSL"), exercised Seven States’s option to purchase from TVA an undivided 90-percent interest in a combined cycle combustion turbine facility in Southaven, Mississippi. As part of interim joint-ownership arrangements, Seven States has the right at any time, and for any reason, until the earlier of the date long-term operational and power sales arrangements are in place or April 23, 2013, to require TVA to buy back Seven States’s interest in the facility. TVA will buy back Seven States's interest if long-term operational and power sales arrangements for the facility among TVA, Seven States, and SSSL, or alternative arrangements, are not in place by April 23, 2013. TVA’s buy-back obligation will terminate if such long-term arrangements are in place by that date. In the event of a buy-back, TVA will re-acquire Seven States's interest in the facility and the related assets. The carrying amount of the Southaven obligation on TVA's balance sheets was approximately $397 million at September 30, 2011, and $413 million at September 30, 2010. On August 8, 2011, a nationally recognized credit rating agency lowered the long-term rating of TVA's rated Bonds from AAA to AA+. This downgrade constituted an event of default under the Amended and Restated Credit Agreement between Seven States and its lenders. Upon the occurrence of such an event of default, Seven States's lenders may either impose a higher default interest rate on the loan or exercise an option to require TVA to re-acquire its interest in the Southaven facility and the related assets. On November 1, 2011, Seven States and its lenders, with the consent of TVA, executed an Amendment to the Amended and Restated Credit Agreement. In this amendment, Seven States's lenders agreed to waive this event of default and thus waive their lenders' right to force TVA to re-acquire Seven States's interest in the Southaven facility and the related assets or to force Seven States to pay the default interest rate for this event of default. Also, the amendment ties the interest rate on Seven States's credit facilities to TVA's credit rating. Seven States will pay interest on the loan at either 1) LIBOR plus 62.5 basis points if TVA's corporate credit rating is AAA (or its equivalent) by all nationally recognized credit rating agencies, or 2) LIBOR plus 87.5 basis points if TVA's corporate credit rating is AA+ (or its equivalent) by one or more nationally recognized credit rating agencies and AAA (or its equivalent) by the other nationally recognized credit agencies. The amendment also states that any future downgrade of TVA's credit rating to below AA+ (or its equivalent) by any nationally recognized credit rating agency would constitute an event of default by Seven States. Because the monthly rent that TVA pays to Seven States for Southaven passes through to TVA the cost of Seven States's loan, TVA's rent payments will increase under this amendment by the amount that Seven States's interest payments on the loan increases, but because of the waiver, the event of default had no other effect on the terms of TVA's lease with Seven States. TVA will continue to present both current and long-term portions of its leaseback obligation to Seven States. At September 30, 2011 and 2010, the total balances of the Leaseback obligations were $1.3 billion and $1.4 billion, respectively.

Leaseback Obligations

Prior to 2004, TVA received approximately $945 million in proceeds by entering into leaseback transactions for 24 new peaking combustion turbine units. TVA also received approximately $389 million in proceeds by entering into a leaseback transaction for qualified technological equipment and software in 2003. Due to TVA’s continuing involvement in the operation and maintenance of the leased units and equipment and its control over the distribution of power produced by the combustion turbine facilities during the leaseback term, TVA accounted for the lease proceeds of $1.3 billion as financing obligations. The outstanding leaseback obligations on TVA's balance sheets were approximately $885 million at September 30, 2011, and $940 million at September 30, 2010.

Seven States Power Corporation ("Seven States"), through its subsidiary, Seven States Southaven, LLC ("SSSL"), exercised Seven States’s option to purchase from TVA an undivided 90-percent interest in a combined cycle combustion turbine facility in Southaven, Mississippi. As part of interim joint-ownership arrangements, Seven States has the right at any time, and for any reason, until the earlier of the date long-term operational and power sales arrangements are in place or April 23, 2013, to require TVA to buy back Seven States’s interest in the facility. TVA will buy back Seven States's interest if long-term operational and power sales arrangements for the facility among TVA, Seven States, and SSSL, or alternative arrangements, are not in place by April 23, 2013. TVA’s buy-back obligation will terminate if such long-term arrangements are in place by that date. In the event of a buy-back, TVA will re-acquire Seven States's interest in the facility and the related assets. The carrying amount of the Southaven obligation on TVA's balance sheets was approximately $397 million at September 30, 2011, and $413 million at September 30, 2010.

On August 8, 2011, a nationally recognized credit rating agency lowered the long-term rating of TVA's rated Bonds from AAA to AA+. This downgrade constituted an event of default under the Amended and Restated Credit Agreement between Seven States and its lenders. Upon the occurrence of such an event of default, Seven States's lenders may either impose a higher default interest rate on the loan or exercise an option to require TVA to re-acquire its interest in the Southaven facility and the related assets.

On November 1, 2011, Seven States and its lenders, with the consent of TVA, executed an Amendment to the Amended and Restated Credit Agreement. In this amendment, Seven States's lenders agreed to waive this event of default and thus waive their lenders' right to force TVA to re-acquire Seven States's interest in the Southaven facility and the related assets or to force Seven States to pay the default interest rate for this event of default. Also, the amendment ties the interest rate on Seven States's credit facilities to TVA's credit rating. Seven States will pay interest on the loan at either 1) LIBOR plus 62.5 basis points if TVA's corporate credit rating is AAA (or its equivalent) by all nationally recognized credit rating agencies, or 2) LIBOR plus 87.5 basis points if TVA's corporate credit rating is AA+ (or its equivalent) by one or more nationally recognized credit rating agencies and AAA (or its equivalent) by the other nationally recognized credit agencies. The amendment also states that any future downgrade of TVA's credit rating to below AA+ (or its equivalent) by any nationally recognized credit rating agency would constitute an event of default by Seven States. Because the monthly rent that TVA pays to Seven States for Southaven passes through to TVA the cost of Seven States's loan, TVA's rent payments will increase under this amendment by the amount that Seven States's interest payments on the loan increases, but because of the waiver, the event of default had no other effect on the terms of TVA's lease with Seven States. TVA will continue to present both current and long-term portions of its leaseback obligation to Seven States.

At September 30, 2011 and 2010, the total balances of the Leaseback obligations were $1.3 billion and $1.4 billion, respectively.