CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2024	Sep. 29, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net Earnings of the Group	$ 852,643	$ 719,656	$ 715,412
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	266,421	148,971	(397,819)
Change in cash flow hedges	(84,193)	(20,500)	154,541
Change in pension plan liabilities	(50,404)	(16,389)	92,527
Other comprehensive income (loss) before taxes	131,824	112,082	(150,751)
Income Tax Benefit (Expense):
Foreign currency translation adjustment	0	1,132	19,019
Cash flow hedges	21,521	5,870	(43,595)
Change in pension plan liabilities	5,159	(1,908)	(5,361)
Income Tax Benefit (Expense):	26,680	5,094	(29,937)
Net other comprehensive income (loss)	158,504	117,176	(180,688)
Net Comprehensive Income of the Group	1,011,147	836,832	534,724
Net Earnings Attributable to Noncontrolling Interests	(31,551)	(32,265)	(36,788)
Net Earnings Attributable to Redeemable Noncontrolling Interests	(14,999)	(21,614)	(34,585)
Net Comprehensive Income Attributable to Jacobs	$ 964,597	$ 782,953	$ 463,351