CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Sep. 27, 2024	Sep. 29, 2023	Sep. 30, 2022
Income Statement [Abstract]
Revenues	$ 11,500,941	$ 10,851,420	$ 9,783,074
Direct cost of contracts	(8,668,185)	(8,140,560)	(7,203,115)
Gross profit	2,832,756	2,710,860	2,579,959
Selling, general and administrative expenses	(2,140,320)	(2,034,376)	(2,040,075)
Operating Profit	692,436	676,484	539,884
Other Income (Expense):
Interest income	34,454	24,975	4,301
Interest expense	(169,058)	(168,085)	(100,187)
Miscellaneous income (expense), net	219,454	(12,399)	33,499
Total other income (expense), net	84,850	(155,509)	(62,387)
Earnings from Continuing Operations Before Taxes	777,286	520,975	477,497
Income Tax Expense for Continuing Operations	(131,493)	(101,336)	(66,328)
Net Earnings of the Group from Continuing Operations	645,793	419,639	411,169
Net Earnings of the Group from Discontinued Operations, net of tax	206,850	300,017	304,243
Net Earnings of the Group	852,643	719,656	715,412
Net Earnings Attributable to Noncontrolling Interests from Continuing Operations	(17,990)	(18,900)	(22,420)
Net Earnings Attributable to Redeemable Noncontrolling Interests	(14,999)	(21,614)	(34,585)
Net Earnings Attributable to Jacobs from Continuing Operations	612,804	379,125	354,164
Net Earnings Attributable to Noncontrolling Interests from Discontinued Operations	(13,561)	(13,365)	(14,368)
Net Earnings Attributable to Jacobs from Discontinued Operations	193,289	286,652	289,875
Net Earnings Attributable to Jacobs	$ 806,093	$ 665,777	$ 644,039
Net Earnings Per Share:
Basic Net Earnings from Continuing Operations Per Share (in dollars per share)	$ 4.81	$ 3.06	$ 2.75
Basic Net Earnings from Discontinued Operations Per Share (in dollars per share)	1.54	2.26	2.25
Basic Earnings Per Share (in dollars per share)	6.35	5.32	5.01
Diluted Net Earnings from Continuing Operations Per Share (in dollars per share)	4.79	3.05	2.74
Diluted Net Earnings from Discontinued Operations Per Share (in dollars per share)	1.54	2.25	2.24
Diluted Earnings Per Share (in dollars per share)	$ 6.32	$ 5.30	$ 4.98