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Restructuring and Other Charges - Schedule of Restructuring and Other Activities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 01, 2022	Jul. 02, 2021	Jul. 01, 2022	Jul. 02, 2021
Restructuring Reserve [Roll Forward]
Beginning balance			$ 14,031
Net(Credits) Charges			19,604
Payments and other			(25,297)
Ending balance	$ 8,338		8,338
Restructuring Cost and Reserve [Line Items]
Other net charges			162,500
People & Places Solutions
Restructuring Reserve [Roll Forward]
Real estate impairment and other transformation activities			71,200
Restructuring Cost and Reserve [Line Items]
Real estate impairment and other transformation activities			71,200
CH2M HILL Companies, Ltd.
Restructuring Reserve [Roll Forward]
Net(Credits) Charges	$ 4,577	$ 13,768	182,100	$ 92,509
Real estate impairment and other transformation activities			77,000
Restructuring Cost and Reserve [Line Items]
Loss related to settlement			91,300
Real estate impairment and other transformation activities			$ 77,000