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v2.4.1.9

Risk Management Activities and Derivative Transactions Derivatives Under FTP (Details) (USD $) | 6 Months Ended |
--- | --- | ---
Mar. 31, 2015 | Sep. 30, 2014
Derivative |  |
FTP transaction limit | 130,000,000 tve_FtpTransactionLimit |
Maximum hedge volume | 75.00%tve_MaximumHedgeVolume |
Market value limitation of outstanding construction materials hedging transactions | 100,000,000 tve_MarketValueLimitationOfOutstandingConstructionMaterialsHedgingTransactions |
Portfolio value at risk limit for foreign currency transactions | 5,000,000 tve_PortfolioValueAtRiskLimitForForeignCurrencyTransactions |
Swap contracts |  |
Derivative |  |
Remaining terms | 3 years |
Coal Contract Derivatives |  |
Derivative |  |
Fair value | 0 us-gaap_DerivativeFairValueOfDerivativeNet / tve_DerivativesUnderFinancialTradingProgramAxis = us-gaap_CoalContractMember | 0 us-gaap_DerivativeFairValueOfDerivativeNet / tve_DerivativesUnderFinancialTradingProgramAxis = us-gaap_CoalContractMember
Futures Contracts |  |
Derivative |  |
Fair value | 0 us-gaap_DerivativeFairValueOfDerivativeNet / tve_DerivativesUnderFinancialTradingProgramAxis = us-gaap_FutureMember |
Options Contract |  |
Derivative |  |
Fair value | 0 us-gaap_DerivativeFairValueOfDerivativeNet / tve_DerivativesUnderFinancialTradingProgramAxis = us-gaap_OptionMember |

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- Definition FTP transaction limit + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition The market value limitation of outstanding hedging transactions involving construction materials. + References No definition available. + Details
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Data Type: | xbrli:monetaryItemType
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- Definition The maximum hedge volume for construction material transactions. + References No definition available. + Details
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Balance Type: | na
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- Definition The portfolio value at risk limit for foreign currency transactions. + References No definition available. + Details
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- Definition Remaining terms + References No definition available. + Details
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- 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/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13495-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 + Details
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- Details
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- Details
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- Details
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- Details
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- Details
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Namespace Prefix: |
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Period Type: |