Discontinued Operations- Schedule of Earnings (Loss) From Discontinued Operations, Net of tax (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 27, 2024	Dec. 29, 2023
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Net (Loss) Earnings of the Group from Discontinued Operations	$ (1,001)	$ 46,639
Net Earnings Attributable to Noncontrolling Interests from Discontinued Operations	0	(3,375)
Net (loss) earnings attributable to Jacobs from discontinued operations	(1,001)	43,264
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff \| SpinCo Business
Disposal Group, Including Discontinued Operation, Income Statement Disclosures [Abstract]
Revenues	64	1,348,998
Direct cost of contracts	(60)	(1,163,190)
Gross profit	4	185,808
Selling, general and administrative expense	(1,348)	(123,745)
Operating (Loss) Profit	(1,344)	62,063
Other income, net	0	482
(Loss) Earnings Before Taxes from Discontinued Operations	(1,344)	62,545
Income Tax Benefit (Expense)	343	(15,332)
Net (Loss) Earnings of the Group from Discontinued Operations	(1,001)	47,213
Net Earnings Attributable to Noncontrolling Interests from Discontinued Operations	0	(3,375)
Net (loss) earnings attributable to Jacobs from discontinued operations	$ (1,001)	$ 43,838

Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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