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v3.20.4

Plant Closures (Details) - USD ($) | 3 Months Ended | 21 Months Ended
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2020
Property, Plant and Equipment [Line Items] |  |  |
Accelerated depreciation | $ 33,000,000 | $ 225,000,000 | $ 986,000,000

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- Definition Accelerated depreciation + References No definition available. + Details
Name: | tve_AcceleratedDepreciation
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration