Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 26, 2020	Jun. 28, 2019	Jun. 26, 2020	Jun. 28, 2019
Statement of Comprehensive Income [Abstract]
Net Earnings of the Group	$ 254,050	$ 531,064	$ 431,517	$ 723,427
Other Comprehensive Income:
Foreign currency translation adjustment	76,288	76,206	12,010	55,157
(Loss) gain on cash flow hedges	(20,944)	(546)	(20,926)	1,592
Change in pension and retiree medical plan liabilities	3,405	27,370	15,872	(14,641)
Other comprehensive income before taxes	58,749	103,030	6,956	42,108
Income Tax (Expense) Benefit:
Foreign currency translation adjustment	(22,062)	0	(3,633)	0
Cash flow hedges	6,262	(35)	6,262	(568)
Change in pension and retiree medical plan liabilities	(8,324)	(6,322)	(4,465)	1,574
Income Tax (Expense) Benefit:	(24,124)	(6,357)	(1,836)	1,006
Net other comprehensive income	34,625	96,673	5,120	43,114
Net Comprehensive Income of the Group	288,675	627,737	436,637	766,541
Net (Earnings) Loss Attributable to Noncontrolling Interests	(9,121)	(6,622)	(21,662)	(17,773)
Net Comprehensive Income Attributable to Jacobs	$ 279,554	$ 621,115	$ 414,975	$ 748,768