Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

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Period Type:	duration

Restructuring and Other Charges - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Oct. 02, 2020	Sep. 27, 2019	Sep. 28, 2018
Restructuring Cost and Reserve [Line Items]
Gain (loss) on sale of business and investments	$ 110,236	$ 935,110	$ 0
Restructuring charges	324,183
CH2M HILL Companies, Ltd.
Restructuring Cost and Reserve [Line Items]
Restructuring charges	324,183	$ 311,332	$ 190,806
Other \| Other Expense \| CH2M HILL Companies, Ltd.
Restructuring Cost and Reserve [Line Items]
Gain (loss) related to settlement	2,100
Write off of Deferred Tax Asset \| CH2M HILL Companies, Ltd.
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 10,000