XML 234 R127.htm IDEA: XBRL DOCUMENT v3.21.2

Revenue Economic Development Incentives (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenues	$ 315	$ 318	$ 310
Unpaid economic incentives	$ (176)	$ (172)

X

- Definition

Economic incentives

+ References

No definition available.

+ Details

Name:	tve_Economicincentives
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Unpaid economic incentives

+ References

No definition available.

+ Details

Name:	tve_Unpaideconomicincentives
Namespace Prefix:	tve_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- References

No definition available.

+ Details

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