Commitments and Contingencies - Capital and Lease Commitments (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Estimate of authorized expenditures required to complete facilities and projects	$ 37

Amount of estimated expenditure to complete facilities and project.

No definition available.

Name:	ten_AmountOfEstimatedExpenditureToCompleteFacilitiesAndProject
Namespace Prefix:	ten_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration