XML 137 R58.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Energy Prepayment Obligations and Discounts on Sales (Details) (USD $) | 12 Months Ended | 24 Months Ended |  | 12 Months Ended | 120 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2014 | Sep. 30, 2013 | Sep. 30, 2012 | Sep. 30, 2004 | Sep. 30, 2004 | Sep. 30, 2014 DEU [Member] | Sep. 30, 2014 MLGW | Sep. 30, 2013 MLGW | Sep. 30, 2012 MLGW | Sep. 30, 2014 MLGW | Sep. 30, 2014 Total | Sep. 30, 2013 Total | Sep. 30, 2012 Total
Energy Prepayment Obligations and Discounts on Sales |  |  |  |  |  |  |  |  |  |  |  |  |
Incremental amount of discounted energy units | $ 1,000,000 |  |  |  |  |  |  |  |  |  |  |  |
Discount per kilowatt-hour | 0.025 |  |  |  |  |  |  |  |  |  |  |  |
Discounted energy units contract period 1 | 5 years |  |  |  |  |  |  |  |  |  |  |  |
Discounted energy units contract period 2 | 10 years |  |  |  |  |  |  |  |  |  |  |  |
Discounted energy units contract period 3 | 15 years |  |  |  |  |  |  |  |  |  |  |  |
Discounted energy units contract period 4 | 20 years |  |  |  |  |  |  |  |  |  |  |  |
Total sales through DEU program since inception |  |  |  |  | 55,000,000 |  |  |  |  |  |  |  |
Deferred Revenue |  |  |  |  |  | 0 |  |  |  |  |  |  |
Deferred revenue, revenue recognized | 1,000,000 | 2,000,000 | 5,000,000 |  |  |  | 100,000,000 | 100,000,000 | 100,000,000 | 1,100,000,000 |  |  |
Discounts reducing electricity sales |  |  |  |  |  |  |  |  |  |  | 46,000,000 | 47,000,000 | 47,000,000
MLGW prepayment |  |  |  | 1,500,000,000 |  |  |  |  |  |  |  |  |
MLGW prepayment period |  |  |  | 180 months |  |  |  |  |  |  |  |  |
Deferred revenue expected recognition each year |  |  |  |  |  |  | $ 100,000,000 |  |  |  |  |  |

X
- Definition Discounted energy units contract period 1 + References No definition available. + Details
Name: | tve_Discountedenergyunitscontractperiod1
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discounted energy units contract period 2 + References No definition available. + Details
Name: | tve_Discountedenergyunitscontractperiod2
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discounted energy units contract period 3 + References No definition available. + Details
Name: | tve_Discountedenergyunitscontractperiod3
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Discounted energy units contract period 4 + References No definition available. + Details
Name: | tve_Discountedenergyunitscontractperiod4
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The discount per kilowatt-hour on a specified quantity of firm power over a period of years. + References No definition available. + Details
Name: | tve_DiscountPerKilowattHour
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The incremental amount that the discounted energy units are available in. + References No definition available. + Details
Name: | tve_IncrementalAmountOfDiscountedEnergyUnits
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Prepayment period + References No definition available. + Details
Name: | tve_PrepaymentPeriod
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Total sales through DEU program since inception of the program. + References No definition available. + Details
Name: | tve_TotalSalesThroughDeuProgramSinceInception
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of deferred revenue as of balance sheet date. Deferred revenue represents collections of cash or other assets related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section A Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.A.4(a).Q1 Response) -URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780 + Details
Name: | us-gaap_DeferredRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of previously reported deferred or unearned revenue that was recognized as revenue during the period. Deferred revenue is a liability related to a revenue producing activity for which revenue has not yet been recognized. Generally, an entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 13.A.4(a).Q1) -URI http://asc.fasb.org/extlink&oid=27012821&loc=d3e214044-122780 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 13 -Section A + Details
Name: | us-gaap_DeferredRevenueRevenueRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_EntityWideInformationRevenueFromExternalCustomerLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase (decrease) during the reporting period, excluding the portion taken into income, in the liability reflecting revenue yet to be earned for which cash or other forms of consideration was received or recorded as a receivable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
Name: | us-gaap_IncreaseDecreaseInDeferredRevenue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of consideration recognized during the period for the milestone or milestones. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 605 -SubTopic 28 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=19771982&loc=SL6892177-166501 + Details
Name: | us-gaap_RevenueRecognitionMilestoneMethodRevenueRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Aggregate cash discounts given by the entity for services rendered to customers for early payments of accounts due. For example, selling terms of "2/10, net 30" entitle a customer to a 2% discount for prompt payment within 10 days, otherwise full payment is expected in 30 days. Discounts are a deduction from gross revenue in arriving at net revenue. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(a)) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 + Details
Name: | us-gaap_SalesDiscountsServices
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration