XML 80 R64.htm IDEA: XBRL DOCUMENT v3.2.0.727

Risk Management Activities and Derivative Transactions Derivatives Under FTP (Details) $ in Millions		9 Months Ended
		Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)
Derivative
FTP transaction limit		$ 130
Maximum hedge volume		75.00%
Market value limitation of outstanding construction materials hedging transactions		$ 100
Portfolio value at risk limit for foreign currency transactions		$ 5
Swap contracts
Derivative
Remaining terms		3 years
Natural Gas Swap
Derivative
Fair value	[1]	$ (125)	$ (103)
Notional amount	[1]	63,835,000	102,227,500
Coal Contract Derivatives
Derivative
Fair value		$ 0	$ 0
Futures Contracts
Derivative
Fair value		0
Options Contract
Derivative
Fair value		$ 0
[1] Fair value amounts presented are based on the net commodity position with the counterparty. Notional amounts disclosed represent the net absolute value of contractual amounts.

X

- Definition

Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher SEC



-Name Regulation S-X (SX)



-Number 210



-Article 12



-Section 13



-Sentence Column B

+ Details

Name:	invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix:	invest_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant

X

- Definition

FTP transaction limit

+ References

No definition available.

+ Details

Name:	tve_FtpTransactionLimit
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The market value limitation of outstanding hedging transactions involving construction materials.

+ References

No definition available.

+ Details

Name:	tve_MarketValueLimitationOfOutstandingConstructionMaterialsHedgingTransactions
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

The maximum hedge volume for construction material transactions.

+ References

No definition available.

+ Details

Name:	tve_MaximumHedgeVolume
Namespace Prefix:	tve_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The portfolio value at risk limit for foreign currency transactions.

+ References

No definition available.

+ Details

Name:	tve_PortfolioValueAtRiskLimitForForeignCurrencyTransactions
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Remaining terms

+ References

No definition available.

+ Details

Name:	tve_Remainingterms
Namespace Prefix:	tve_
Data Type:	us-types:durationStringItemType
Balance Type:	na
Period Type:	duration

X

- 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 815



-SubTopic 10



-Section 45



-Paragraph 6



-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958



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 10



-Subparagraph (a)



-URI http://asc.fasb.org/extlink&oid=49121117&loc=d3e13433-108611



Reference 4: 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=49121117&loc=d3e13495-108611

+ Details

Name:	us-gaap_DerivativeFairValueOfDerivativeNet
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

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_DerivativeByNatureAxis=us-gaap_SwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	tve_DerivativesUnderFinancialTradingProgramAxis=tve_NaturalGasSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	tve_DerivativesUnderFinancialTradingProgramAxis=us-gaap_CoalContractMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	tve_DerivativesUnderFinancialTradingProgramAxis=us-gaap_FutureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	tve_DerivativesUnderFinancialTradingProgramAxis=us-gaap_OptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: