XML 96 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Allowance for Uncollectible Accounts (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Sep. 30, 2018 | Sep. 30, 2017
Allowance for Uncollectible Accounts |  |
Revenue Capitalized During Pre-Commercial Operations | $ 11 | $ 22
Period of time for customers to fulfill payment arrangements | 90 days |
Allowance for uncollectible accounts - receivables | $ 0 | 1
Loans receivable | 123 | 107
Allowance for uncollectible accounts - loans |  | 1
Fuel Cost Capitalized During Pre-Commercial Operations | $ 19 | $ 14

X
- References No definition available. + Details
Name: | srt_ValuationAndQualifyingAccountsDisclosureLineItems
Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fuel costs incurred during pre-commercial generation capitalized to project costs. + References No definition available. + Details
Name: | tve_FuelCostCapitalizedDuringPreCommercialOperations
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition Period of time for customers to fulfill payment arrangements + References No definition available. + Details
Name: | tve_Periodoftimeforcustomerstofulfillpaymentarrangements
Namespace Prefix: | tve_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimates of revenue realized from pre-commercial generation based on the guidance provided by FERC regulations. The calculated revenue is capitalized to offset project costs and is included in revenue as a contra-revenue amount + References No definition available. + Details
Name: | tve_RevenueCapitalizedDuringPreCommercialOperations
Namespace Prefix: | tve_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | duration

X
- Definition A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition A valuation allowance relating to a written agreement to receive money (at a specified future date(s) more than one year from the reporting date, consisting of principal as well as any accrued interest) for the portion that is expected to be uncollectible. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5074-111524 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.4) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AllowanceForNotesAndLoansReceivableNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Net amount of the investment in a contractual right to receive money on demand or on fixed or determinable dates that is recognized as an asset in the creditor's statement of financial position. Examples include, but are not limited to, credit card receivables, notes receivable and receivables relating to lessor's rights to payments from leases other than operating leases that have been recorded as assets. Excludes trade accounts receivable with contractual maturity of one year or less and arose from the sale of goods or services. + References 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 210.5-02.3) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_NotesReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant