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Plant Closures (Notes) | 12 Months Ended
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Sep. 30, 2019
Property, Plant and Equipment [Abstract] |
Plant Retirement and Abandonment, Policy [Policy Text Block] | 6. Plant Closures Background TVA must continuously evaluate all generating assets to ensure an optimum energy portfolio that provides safe, clean, and reliable power while maintaining flexibility and fiscal responsibility to the people of the Tennessee Valley. During its August 2018 meeting, the TVA Board approved a plan to perform assessments of Bull Run Fossil Plant ("Bull Run") and Paradise Fossil Plant ("Paradise"). These assessments included resiliency studies for fuel and transmission and financial considerations. TVA also prepared Environmental Assessments ("EAs") pursuant to the National Environmental Policy Act ("NEPA"). Results of these assessments were presented to the TVA Board at its February 2019 meeting, and the Board approved the retirement of Paradise Unit 3 by December 2020 and Bull Run by December 2023. Subsequent to the Board approval, TVA determined that Paradise would not be restarted after January 2020 due to the plant's material condition. Financial Impact As a result of TVA's decision to accelerate the retirements of Paradise and Bull Run, certain construction projects at these locations were identified as probable of abandonment or were no longer expected to be in service for greater than one year prior to the plants' retirement dates. The write-off of these projects resulted in $151 million of Operating and maintenance expense during the year ended September 30, 2019. TVA also recognized losses of $19 million in Operating and maintenance expense related to additional materials and supplies inventory reserves and write-offs identified at Paradise during the year ended September 30, 2019. TVA's policy is to adjust depreciation rates to reflect the most current assumptions, ensuring units will be fully depreciated by the applicable retirement dates. As a result of TVA's decision to accelerate the retirement of Paradise and Bull Run, TVA recognized an additional $566 million of accelerated depreciation for the year ended September 30, 2019.

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- Definition Disclosure of accounting policy for plant retirement and for abandonment (under construction or in use) in regulated industries when abandonment becomes probable. Any difference between the new asset and the asset cost is recognized as a loss in the income statement. May also indicate the discount rate used in the calculation of present value of recoverable abandoned assets. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section 35 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45591-110387 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section 35 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45573-110387 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 980 -SubTopic 360 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45555-110387 + Details
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