XML 77 R65.htm IDEA: XBRL DOCUMENT
v3.24.1.u1

Employee Benefits (Details) - USD ($) $ in Millions | 3 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2023 | Mar. 31, 2024 | Oct. 01, 2023
Retirement Benefits [Abstract] |  |  |
Government assistance noncurrent liability |  |  | $ 21
Government assistance decrease in liability | $ 10 |  |
Government assistance current liability |  | $ 11 |

X
- Definition Government Assistance, Liability, Current + References No definition available. + Details
Name: | ttek_GovernmentAssistanceLiabilityCurrent
Namespace Prefix: | ttek_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Government Assistance, Liability, Decrease + References No definition available. + Details
Name: | ttek_GovernmentAssistanceLiabilityDecrease
Namespace Prefix: | ttek_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Government Assistance, Liability, Noncurrent + References No definition available. + Details
Name: | ttek_GovernmentAssistanceLiabilityNoncurrent
Namespace Prefix: | ttek_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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