CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 28, 2025	Mar. 29, 2024	Mar. 28, 2025	Mar. 29, 2024
Income Statement [Abstract]
Revenues	$ 2,910,415	$ 2,847,179	$ 5,843,371	$ 5,657,406
Direct cost of contracts	(2,172,070)	(2,135,217)	(4,383,759)	(4,280,715)
Gross profit	738,345	711,962	1,459,612	1,376,691
Selling, general and administrative expenses	(529,697)	(528,718)	(1,042,546)	(1,051,448)
Operating Profit	208,648	183,244	417,066	325,243
Other Income (Expense):
Interest income	9,525	8,702	19,181	16,221
Interest expense	(38,580)	(44,232)	(73,399)	(87,583)
Loss on extinguishment of debt	(20,510)	0	(20,510)	0
Miscellaneous expense	(103,260)	(3,705)	(233,367)	(6,668)
Total other expense, net	(152,825)	(39,235)	(308,095)	(78,030)
Earnings from Continuing Operations Before Taxes	55,823	144,009	108,971	247,213
Income Tax Expense from Continuing Operations	(50,576)	(43,364)	(107,725)	(11,754)
Net Earnings of the Group from Continuing Operations	5,247	100,645	1,246	235,459
Net (Loss) Earnings of the Group from Discontinued Operations, net of tax	(5,550)	72,889	(6,551)	119,530
Net (Loss) Earnings of the Group	(303)	173,534	(5,305)	354,989
Net Loss (Earnings) Attributable to Noncontrolling Interests from Continuing Operations	11,731	(4,327)	5,651	(8,179)
Net Earnings Attributable to Redeemable Noncontrolling interests	(5,816)	(4,082)	(12,863)	(6,700)
Net Earnings (Loss) Attributable to Jacobs from Continuing Operations	11,162	92,236	(5,966)	220,580
Net Earnings Attributable to Noncontrolling Interests from Discontinued Operations	0	(3,013)	0	(6,388)
Net (Loss) Earnings Attributable to Jacobs from Discontinued Operations	(5,550)	69,876	(6,551)	113,142
Net Earnings (Loss) Attributable to Jacobs	$ 5,612	$ 162,112	$ (12,517)	$ 333,722
Net Earnings Per Share:
Basic Net Earnings from Continuing Operations Per Share (in dollars per share)	$ 0.10	$ 0.73	$ 0	$ 1.77
Basic Net (Loss) Earnings from Discontinued Operations Per Share (in dollars per share)	(0.05)	0.56	(0.05)	0.90
Basic Earnings (Loss) Per Share (in dollars per share)	0.06	1.29	(0.05)	2.66
Diluted Net Earnings from Continuing Operations Per Share (in dollars per share)	0.10	0.73	0	1.76
Diluted Net (Loss) Earnings from Discontinued Operations Per Share (in dollars per share)	(0.05)	0.55	(0.05)	0.89
Diluted Earnings (Loss) Per Share (in dollars per share)	$ 0.06	$ 1.28	$ (0.05)	$ 2.65