XML 194 R87.htm IDEA: XBRL DOCUMENT v3.21.2

Risk Management Activities and Derivative Transactions Risk Management Activities and Derivative Transactions - Counterparty Credit Risk (Details) $ in Millions	12 Months Ended
	Sep. 30, 2021 USD ($) megawatts Customers	Sep. 30, 2020 USD ($)
Derivative
Receivables from power sales | $	$ 1,480	$ 1,401
Credit of Customers
Derivative
Number of customers that represent the percent of sales | Customers	2
Long-term Contract for Purchase of Electric Power [Domain]
Derivative
Megawatts | megawatts	440

X

- Definition

Megawatts of summer net capability

+ References

No definition available.

+ Details

Name:	tve_Megawatts
Namespace Prefix:	tve_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of customers that represent the percent of sales

+ References

No definition available.

+ Details

Name:	tve_Numberofcustomersthatrepresentthepercentofsales
Namespace Prefix:	tve_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4531-111522

+ Details

Name:	us-gaap_AccountsReceivableGrossCurrent
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_DerivativeInstrumentRiskAxis=tve_CreditOfCustomersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_LongTermContractForPurchaseOfElectricPowerDomain
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: