XML 100 R76.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Risk Management Activities and Derivative Transactions Counterparty Credit Risk (Details) $ in Millions | 3 Months Ended |
--- | --- | ---
Dec. 31, 2024 USD ($) Customers | Dec. 31, 2023 | Sep. 30, 2024 USD ($)
Derivative |  |  |
Accounts Receivable, before Allowance for Credit Loss, Current | $ | $ 1,569 |  | $ 1,683
Two Largest Customer Percentage of Total Operating Revenue | 1600.00% | 1600.00% |
Moody's, A1 Rating [Member] |  |  |
Derivative |  |  |
Natural Gas Banking Counterparties Credit Rating | A1 |  |
Moody's, B1 Rating [Member] |  |  |
Derivative |  |  |
Natural Gas Banking Counterparties Credit Rating | B1 |  |
Moody's, A2 Rating |  |  |
Derivative |  |  |
Banking Counterparties Credit Rating | A2 |  |
Credit of Customers |  |  |
Derivative |  |  |
Number of customers that represent the percent of sales | 2 |  |
Number of customers that represent the percent of sales | 2 |  |

X
- Definition Banking Counterparties Credit Rating + References No definition available. + Details
Name: | tve_BankingCounterpartiesCreditRating
Namespace Prefix: | tve_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Natural Gas Banking Counterparties Credit Rating + References No definition available. + Details
Name: | tve_NaturalGasBankingCounterpartiesCreditRating
Namespace Prefix: | tve_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of customers that represent the percent of sales + References No definition available. + Details
Name: | tve_Numberofcustomersthatrepresentthepercentofsales
Namespace Prefix: | tve_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition This concept explains the total percentage of operating revenue provided by the two largest customers. + References No definition available. + Details
Name: | tve_TwoLargestCustomerPercentageOfTotalOperatingRevenue
Namespace Prefix: | tve_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 310 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481990/310-10-45-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)(a)(1)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org/1943274/2147483467/210-10-45-1 + Details
Name: | us-gaap_AccountsReceivableGrossCurrent
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: | srt_CreditRatingMoodysAxis=srt_MoodysA1RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysB1RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CreditRatingMoodysAxis=srt_MoodysA2RatingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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