Name:	tve_Commoditycontractderivativeliabilitiesfairvaluedisclosure
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This item represents the amount of the total realized and unrealized gains or losses for the period which are deferred as regulatory assets and liabilities; the fair value of which assets or liabilities was or is measured on a recurring basis using significant unobservable inputs (Level 3).

No definition available.

Name:	tve_FairValueAssetsOrLiabilitiesMeasuredOnRecurringBasisGainLossDeferredAsRegulatoryAssetsOrLiabilities
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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

The fair value measurement of tons per year used to determine fair value

No definition available.

Name:	tve_FairValueMeasurementsTonsPerYear
Namespace Prefix:	tve_
Data Type:	num:weightItemType
Balance Type:	na
Period Type:	instant

The price per ton used for the determination of fair value.

No definition available.

Name:	tve_PricePerTon
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
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- References

No definition available.

Name:	us-gaap_AssetsAbstract
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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.

No definition available.

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems
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Fair value of financial instrument classified as derivative asset (liability) after deduction of derivative liability (asset), measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19279-110258

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The fair value as of the balance sheet date of firm holdings in physical commodity contracts (for example, agricultural products, metals and energy). Includes both pledged (to counterparties as collateral for financing transactions) and unpledged holdings.

No definition available.

Name:	us-gaap_FinancialInstrumentsOwnedPhysicalCommoditiesAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

Name:	us-gaap_LiabilitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	srt_RangeAxis=srt_MinimumMember
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Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
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Name:	tve_FairValueByClassAxis=us-gaap_CommodityContractMember
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