Kingston Fossil Plant Ash Spill	12 Months Ended
Kingston Fossil Plant Ash Spill	Sep. 30, 2011
Environmental Remediation Obligations [Abstract]
Kingston Fossil Plant Ash Spill	Kingston Fossil Plant Ash Spill The Event In December 2008, one of the dredge cells at Kingston failed, and approximately five million cubic yards of water and coal fly ash flowed out of the cell. TVA is continuing cleanup and recovery efforts in conjunction with federal and state agencies. TVA completed the removal of time-critical ash from the river during the third quarter of 2010, and removal of the remaining ash is considered to be non-time-critical. TVA estimates that the physical cleanup work (final removal) will be completed in the last quarter of 2014. A final assessment, a completion report, and approval by Tennessee and the EPA is expected to occur by the second quarter of 2015. Surveillance and monitoring of the site will continue, but this work is beyond the scope of the cleanup project. Claims and Litigation See Note 20 — Legal Proceedings — Legal Proceedings Related to the Kingston Ash Spill and — Civil Penalty and Natural Resource Damages for the Kingston Ash Spill. Financial Impact Because of the uncertainty at this time of the final costs to complete the work prescribed by the ash disposal plan, a range of reasonable estimates has been developed by cost category. Known amounts, most likely scenarios, or the low end of the range for each category have been accumulated and evaluated to determine the total estimate. The range of estimated costs varies from approximately $1.1 billion to approximately $1.2 billion. TVA recorded an estimate of $1.1 billion for the cost of cleanup related to this event. In August 2009, TVA began using regulatory accounting treatment to defer all actual costs already incurred and expected future costs related to the ash spill. The cost is being charged to expense as it is collected in rates over 15 years, beginning October 1, 2009. As the estimate changes, additional costs may be deferred and charged to expense prospectively as they are collected in future rates. As work continues to progress and more information is available, TVA will review its estimates and revise them as appropriate. TVA has accrued a portion of the estimated cost in current liabilities, with the remaining portion shown as a long-term liability on TVA’s balance sheets. Amounts spent since the event through September 30, 2011, totaled $749 million. The remaining estimated liability at September 30, 2011, was $376 million. TVA has not included the following categories of costs in the above estimate since it has been determined that these costs are currently either not probable or not reasonably estimable: penalties (other than the penalties set out in the June 2010 Tennessee Department of Environment and Conservation ("TDEC") order), regulatory directives, natural resources damages (other than payments required under a memorandum of agreement with TDEC and the Fish and Wildlife Service establishing a process and a method for resolving the natural resource damages claim), future lawsuits, future claims, long-term environmental impact costs, final long-term disposition of ash processing area, costs associated with new laws and regulations, or cost of remediating any ash which is commingled with radioactive material from non-TVA operations, to the extent it would have to be managed as low-level radioactive waste. There are certain other costs that will be incurred that have not been included in the estimate as they are appropriately accounted for in other areas of the financial statements. Associated capital asset purchases are recorded in property, plant, and equipment. Ash handling and disposition costs from current plant operations are recorded in operating expenses. A portion of the pond and dredge cell closure costs is also not included in the estimate as it is included in the non-nuclear ARO liability. Insurance TVA had property and excess liability insurance programs in place at the time of the Kingston ash spill. TVA pursued claims under both the property and excess liability programs and has settled all of its property insurance claims and some of its excess liability insurance claims. Through September 30, 2011, TVA received proceeds of $40 million. TVA continues to provide information about the nature and extent of TVA’s claims under the policies to the remaining excess liability insurance companies. It is unclear at this time whether the parties will be able to resolve the outstanding claims without resorting to the policies’ dispute resolution procedures. Any amounts received related to insurance settlements are being recorded as reductions to the regulatory asset and will reduce amounts collected in future rates.

The entire disclosure for environmental loss contingencies, such as presence of hazardous waste, relevant information from reports issued by regulators, and estimated costs to achieve compliance with regulatory requirements. This element may be used for all of an entity's disclosures about environmental loss contingencies.