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Amount of realized and unrealized gain (loss) on investment.

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Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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The net result for the period of deducting operating expenses from operating revenues.

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Carrying amount as of the balance sheet date of known and reasonably estimable amounts of recoveries from third-parties pertaining to an entity's environmental remediation obligations. An entity's balance sheet may include several assets that relate to an environmental remediation obligation. Among them are the following: a. Receivables from other potentially responsible parties that are not providing initial funding; b. anticipated recoveries from insurers; and c. anticipated recoveries from prior owners as a result of indemnification agreements.

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Segment Information - Schedule of Total Revenues, Segment Operating Profit and Total Asset for Reporting Segment (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Oct. 01, 2021	Oct. 02, 2020
Segment Reporting Information [Line Items]
Total Segment Operating Profit		$ 917,850	$ 688,089	$ 535,973
Restructuring, Transaction and Other Charges		(197,884)	(350,394)	(327,413)
Total Other (Expense) Income, net		(41,503)	7,513	(94,770)
Earnings from Continuing Operations Before Taxes		876,347	695,602	441,203
Gain (loss) on litigation settlement		19,500
Loss related to litigation settlement		(19,500)
Intangibles amortization		198,600	149,800	90,600
Recorded third-party environmental recoveries receivable	$ 27,000	27,000
Impairment of real estate		71,000	2,400	161,400
Cost incurred in investment			297,800
Gain related to cost-method Investments		13,900
Gain on termination of lease		8,700
Impairment of equity method investment				(162,000)
JKC Australia L N G Pty Limited \| Settled Litigation
Segment Reporting Information [Line Items]
Gain (loss) on litigation settlement		(91,300)
Loss related to litigation settlement		91,300
AWE ML
Segment Reporting Information [Line Items]
Gain on termination of lease		8,700
Impairment of equity method investment			(38,500)
C3.ai. Inc.
Segment Reporting Information [Line Items]
Fair value adjustments			(49,600)
ECR Business
Segment Reporting Information [Line Items]
Fair value adjustments			34,700	(74,300)
CH2M HILL Companies, Ltd.
Segment Reporting Information [Line Items]
Impairment of real estate	$ 78,300		2,400	161,400
Gain on termination of lease		(8,700)
Impairment of equity method investment		(91,300)
Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit		1,480,174	1,378,612	1,112,777
Corporate Non Segment
Segment Reporting Information [Line Items]
Other Corporate Expenses		(364,440)	(340,129)	(249,391)
Critical Mission Solutions \| Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit		424,385	447,161	372,070
People & Places Solutions \| Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit		823,564	780,380	740,707
PA Consulting \| Operating Segments
Segment Reporting Information [Line Items]
Total Segment Operating Profit		$ 232,225	$ 151,071	$ 0