XML 96 R72.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Risk Management Activities and Derivative Transactions Derivatives Under FTP (Details) - USD ($) $ in Millions | Dec. 31, 2024 | Sep. 30, 2024
--- | --- | ---
Derivative |  |
Forward Contract Derivative Asset, at Fair Value | $ 9 | $ 11
Fair value | 32 | 64
Commodity Contract under FHP |  |
Derivative |  |
Fair value | (75) | (161)
Fair Value, Inputs, Level 2 |  |
Derivative |  |
Forward Contract Derivative Asset, at Fair Value | $ 9 | $ 11

X
- Definition Fair value as of the balance sheet date of forward contract derivative assets. + References No definition available. + Details
Name: | tve_ForwardContractDerivativeAssetatFairValue
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 825 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 10 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482907/825-10-50-10 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 815 -SubTopic 40 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480237/815-40-50-5 + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=tve_CommodityContractUnderFHPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |