XML 202 R114.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Commitments and Contingencies - Contingencies (Details) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2022 USD ($) Insurance_layers reactors Units Procedures | Sep. 30, 2021 USD ($) | Sep. 30, 2020 USD ($)
Contingencies |  |  |  |
Loss Contingency, Damages Sought, Value |  | $ 30 |  |
Nuclear liability insurance |  | 450 |  |
Assessment from licensees for each licensed reactor |  | $ 138 |  |
Number of licensed reactors in US | reactors |  | 96 |  |
Nuclear accident assessment limitation per year per unit |  | $ 20 |  |
Number of licensed nuclear units | Units |  | 7 |  |
Maximum assessment per nuclear incident |  | $ 963 |  |
Total amount of protection available |  | $ 13,700 |  |
Number of layers until the U.S. Congress is required to take action | Insurance_layers |  | 2 |  |
Amount of insurance available for loss at any one site |  | $ 2,100 |  |
Maximum amount of retrospective premiums |  | 115 |  |
Maximum idemnity if a covered accident tasks or keeps a nuclear unit offline |  | 490 |  |
Maximum amount of retrospective premiums |  | 44 |  |
Estimated future decommissioning cost | [1] | $ 7,162 | $ 7,002 | $ 6,785
Number of procedures for determining estimates for the costs of nuclear decommissioning | Procedures |  | 2 |  |
Amount spent to reduce emissions since 1970 |  | $ 6,800 |  |
Amount spent to reduce emissions |  | 16 | 17 | 19
Possible additional future costs for compliance with Clean Air Act requirements |  | 128 |  |
Possible additional future costs for compliance with CCR requirements |  | 900 |  |
Possible additional future costs for compliance with Clean Water requirements. |  | 111 |  |
Estimated liability for cleanup and similar environmental work on a non-discounted basis |  | 17 | 18 |
Amount of insurance available for loss at any one site, max |  | 2,800 |  |
Nuclear |  |  |  |
Contingencies |  |  |  |
Estimated future decommissioning cost |  | 3,643 | 3,428 | 3,278
Non-nuclear |  |  |  |
Contingencies |  |  |  |
Estimated future decommissioning cost |  | $ 3,519 | $ 3,574 | $ 3,507
[1] | (1) Includes $275 million a nd $266 million at September 30, 2022 and 2021, respectively, in Current liabilities. (2) Settlements include the change in asset retirement obligation project accruals included in Accounts payable and accrued liabilities of $20 million.

X
- Definition The amount of property, decommissioning, and decontamination insurance available for loss at any one site to cover the cost of stabilizing or shutting down a reactor after an accident. + References No definition available. + Details
Name: | tve_AmountOfInsuranceAvailableForLossAtAnyOneSite
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of insurance available for loss at any one site, max + References No definition available. + Details
Name: | tve_AmountOfInsuranceAvailableForLossAtAnyOneSiteMax
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The amount spent to reduce emissions at power plants. + References No definition available. + Details
Name: | tve_AmountSpentToReduceEmissions
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount spent since 1970 to reduce emissions at power plants. + References No definition available. + Details
Name: | tve_AmountSpentToReduceEmissionsSince1970
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition An assessment from licensees for each licensed nuclear reactor in the United States to fund the second layer, the Secondary Financial Program. + References No definition available. + Details
Name: | tve_AssessmentFromLicenseesForEachLicensedReactor
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Maximum assessment per nuclear incident. + References No definition available. + Details
Name: | tve_MaximumAssessmentPerNuclearIncident
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The maximum idemnity per unit if an accident covered by the policy tasks or keeps a nuclear unit offline. + References No definition available. + Details
Name: | tve_MaximumIdemnityIfCoveredAccidentTasksOrKeepsNuclearUnitOffline
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The maximum amount of retrospective premiums that may be required for property, decommissioning, and decontamination insurance. + References No definition available. + Details
Name: | tve_Maximumamountofretrospectivepremiums
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The per year per unit limitation of the assessment for any nuclear accident + References No definition available. + Details
Name: | tve_NuclearAccidentAssessmentLimitationPerYearPerUnit
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition For the first layer of protection all NRC nuclear plant licensees purchase nuclear insurance from American Nuclear Insurers for each nuclear plant with an operating license. + References No definition available. + Details
Name: | tve_NuclearLiabilityInsurance
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of licensed nuclear units owned. + References No definition available. + Details
Name: | tve_NumberOfLicensedNuclearUnits
Namespace Prefix: | tve_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of procedures for determining estimates for the costs of nuclear decommissioning + References No definition available. + Details
Name: | tve_NumberOfProceduresForDeterminingEstimatesForCostsOfNuclearDecommissioning
Namespace Prefix: | tve_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of licensed reactors in US. + References No definition available. + Details
Name: | tve_NumberoflicensedreactorsinUS
Namespace Prefix: | tve_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The possible additional future costs for compliance with Clean Air Act requirements. + References No definition available. + Details
Name: | tve_PossibleAdditionalFutureCostsForComplianceWithCleanAirActRequirements
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The possible additional future costs for compliance with CCR requirements + References No definition available. + Details
Name: | tve_PossibleadditionalfuturecostsforcompliancewithCCRrequirements
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The possible additional future costs for compliance with Clean Water requirements. + References No definition available. + Details
Name: | tve_PossibleadditionalfuturecostsforcompliancewithCleanWaterrequirements.
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The maximum amount of retrospective premiums that could be required for accidental outage insurance. + References No definition available. + Details
Name: | tve_RetrospectivePremiums
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The total amount of protection available to compensate for losses arising from a nuclear event in the United States. + References No definition available. + Details
Name: | tve_TotalAmountOfProtectionAvailable
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition The U.S. Congress is required to take action to provide additional funds to cover the additional losses if these layes are exhausted. + References No definition available. + Details
Name: | tve_USCongressIsRequiredToTakeActionIfTheseLayesAreExhausted
Namespace Prefix: | tve_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Undiscounted amount of the accrual for environmental loss contingencies. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 7 -URI https://asc.fasb.org/extlink&oid=6393242&loc=d3e13207-110859 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 5.Y.Q1) -URI https://asc.fasb.org/extlink&oid=27011672&loc=d3e149879-122751 + Details
Name: | us-gaap_AccrualForEnvironmentalLossContingenciesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 25 -Paragraph 4 -URI https://asc.fasb.org/extlink&oid=116646717&loc=d3e6290-110844 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI https://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The value (monetary amount) of the award the plaintiff seeks in the legal matter. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 9 -Subparagraph (a) -URI https://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349 + Details
Name: | us-gaap_LossContingencyDamagesSoughtValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | tve_ReconciliationOfAssetRetirementObligationLiabilityAxis=tve_NuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | tve_ReconciliationOfAssetRetirementObligationLiabilityAxis=tve_NonNuclearMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |