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Minimum investment period of private partnership investments.

No definition available.

Name:	tve_Minimuminvestmentperiod
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The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning nuclear facilities.

No definition available.

Name:	tve_NuclearDecommissioningFundInvestmentsFairValue
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

Number of readily available quoted exchange prices for the investments

No definition available.

Name:	tve_NumberOfReadilyAvailableQuotedExchangePricesForInvestments
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Period of time where the investor contributes capital to an investment in a private partnership - maximum

No definition available.

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Period of time where the investor contributes capital to an investment in a private partnership - minimum

No definition available.

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Fair value portion of arrangements with third parties, including, but not limited to, operating lease arrangement and arrangement in which the entity has agreed to expend funds to procure goods or services, or has agreed to commit resources to supply goods or services.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(25))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 410
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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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.

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The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.12)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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Period Type:	instant

Amount of unrealized gain (loss) on investment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

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Name:	us-gaap_InvestmentTypeAxis=tve_ArtMember
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Name:	us-gaap_InvestmentTypeAxis=tve_NdtMember
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