CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 29, 2024	Mar. 31, 2023	Mar. 29, 2024	Mar. 31, 2023
Income Statement [Abstract]
Revenues	$ 4,269,093	$ 4,078,332	$ 8,428,318	$ 7,877,001
Direct cost of contracts	(3,364,478)	(3,188,038)	(6,673,165)	(6,171,994)
Gross profit	904,615	890,294	1,755,153	1,705,007
Selling, general and administrative expenses	(623,627)	(600,431)	(1,270,101)	(1,177,339)
Operating Profit	280,988	289,863	485,052	527,668
Other Income (Expense):
Interest income	9,405	7,630	17,639	10,637
Interest expense	(44,232)	(40,613)	(87,584)	(80,690)
Miscellaneous expense, net	(4,576)	(4,567)	(7,771)	(7,820)
Total other expense, net	(39,403)	(37,550)	(77,716)	(77,873)
Earnings from Continuing Operations Before Taxes	241,585	252,313	407,336	449,795
Income Tax expense from Continuing Operations	(67,283)	(19,060)	(51,005)	(69,163)
Net Earnings of the Group from Continuing Operations	174,302	233,253	356,331	380,632
Net Loss of the Group from Discontinued Operations	(768)	(75)	(1,342)	(783)
Net Earnings of the Group	173,534	233,178	354,989	379,849
Net Earnings Attributable to Noncontrolling Interests from Continuing Operations	(7,340)	(7,803)	(14,567)	(14,834)
Net Earnings Attributable to Redeemable Noncontrolling interests	(4,082)	(8,863)	(6,700)	(12,855)
Net Earnings Attributable to Jacobs from Continuing Operations	162,880	216,587	335,064	352,943
Net Earnings Attributable to Jacobs	$ 162,112	$ 216,512	$ 333,722	$ 352,160
Net Earnings Per Share:
Basic Net Earnings from Continuing Operations Per Share (in dollars per share)	$ 1.30	$ 1.71	$ 2.68	$ 2.78
Basic Net Loss from Discontinued Operations Per Share (in dollars per share)	(0.01)	0	(0.01)	(0.01)
Basic Earnings Per Share (in dollars per share)	1.29	1.71	2.66	2.78
Diluted Net Earnings from Continuing Operations Per Share (in dollars per share)	1.29	1.70	2.66	2.77
Diluted Net Loss from Discontinued Operations Per Share (in dollars per share)	(0.01)	0	(0.01)	(0.01)
Diluted Earnings Per Share (in dollars per share)	$ 1.28	$ 1.70	$ 2.65	$ 2.76