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Legal Proceedings and Commitments and Contingencies (Details) - USD ($) $ in Millions	1 Months Ended
	Jan. 31, 2020	Sep. 27, 2024	Sep. 29, 2023
Loss Contingencies [Line Items]
Estimate of possible loss		$ 138	$ 138
Other long-term liabilities		$ 125	$ 125
AECOM Energy & Construction Inc.
Loss Contingencies [Line Items]
Percentage of claim recovery and costs assumed	10.00%
Percentage of claim recovery and costs retained by seller	90.00%

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