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Sale of Energy, Chemicals and Resources ("ECR") Business - Narrative (Details) - USD ($) $ in Thousands, shares in Millions		3 Months Ended	12 Months Ended
	Apr. 26, 2019	Apr. 02, 2021	Sep. 30, 2022	Oct. 01, 2021	Oct. 02, 2020	Sep. 27, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
(Gain) loss on investment in equity securities			$ (13,862)	$ (71,325)	$ 103,623
Worley Stock
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Equity instrument consideration, shares	58.2
(Gain) loss on investment in equity securities				(40,700)	(103,600)
Worley Stock \| Restricted Stock
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Dividend income				19,100	16,900
ECR Business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration transferred	$ 3,400,000
Business combination consideration paid in cash	2,800,000
ECR Business \| Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on sale of businesses	$ 1,100,000	$ 15,600		$ 15,600	$ 110,200	$ 935,100
Proceeds from Legal Settlements		$ 36,400