XML 80 R55.htm IDEA: XBRL DOCUMENT
v3.25.2

Summary of Significant Accounting Policies Revenues (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024 | Sep. 30, 2024
Property, Plant and Equipment [Line Items] |  |  |  |  |
Pre-commercial Ops - capitalized revenue | $ 1 | $ 0 | $ 3 | $ (3) |
Accounts and Financing Receivable, Allowance for Credit Loss | 2 |  | 2 |  | $ 2
Paradise CT Units 5-7 |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Pre-commercial Ops - capitalized revenue |  |  |  | 3 |
Pre-commercial Ops - Capitalized Fuel |  |  |  | $ 3 |
Johnsonville Aeroderivative CT Units 25-28 |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |
Pre-commercial Ops - capitalized revenue | 1 |  | 3 |  |
Pre-commercial Ops - Capitalized Fuel | $ 2 |  | $ 6 |  |

X
- Definition Pre-commercial Ops - Capitalized Fuel + References No definition available. + Details
Name: | tve_PreCommercialOpsCapitalizedFuel
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Pre-commercial Ops - capitalized revenue + References No definition available. + Details
Name: | tve_PreCommercialOpsCapitalizedRevenue
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of allowance for credit loss of accounts and financing receivables. Includes, but is not limited to, notes and loan receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481962/310-10-50-4 + Details
Name: | us-gaap_AccountsAndFinancingReceivableAllowanceForCreditLoss
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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A + Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PublicUtilityAxis=tve_ParadiseCTUnits57Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PublicUtilityAxis=tve_JohnsonvilleAeroderivativeCTUnits2130Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |