Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Consolidated Statements of Operations
Revenue	$ 3,408,357	$ 3,189,679	$ 9,987,085	$ 9,671,026
Cost of revenue	3,206,823	3,004,600	9,405,922	9,151,334
Gross profit	201,534	185,079	581,163	519,692
Equity in earnings of joint ventures	8,270	8,573	23,628	32,006
General and administrative expenses	(36,340)	(54,482)	(110,707)	(139,133)
Restructuring costs	(12,971)	(20,300)	(34,755)	(96,438)
Income from operations	160,493	118,870	459,329	316,127
Other income	4,482	3,119	11,812	9,557
Interest expense	(149,038)	(34,925)	(212,489)	(112,413)
Income from continuing operations before taxes	15,937	87,064	258,652	213,271
Income tax (benefit) expense for continuing operations	(17,938)	(7,184)	42,811	30,326
Net income from continuing operations	33,875	94,248	215,841	182,945
Net loss from discontinued operations	(15,502)	(126)	(119,168)	(112,695)
Net income	18,373	94,122	96,673	70,250
Net income attributable to noncontrolling interests from continuing operations	(5,901)	(3,138)	(16,160)	(12,428)
Net income attributable to noncontrolling interests from discontinued operations	(941)	(1,645)	(3,495)	(14,005)
Net income attributable to noncontrolling interests	(6,842)	(4,783)	(19,655)	(26,433)
Net income attributable to AECOM from continuing operations	27,974	91,110	199,681	170,517
Net loss attributable to AECOM from discontinued operations	(16,443)	(1,771)	(122,663)	(126,700)
Net income attributable to AECOM	$ 11,531	$ 89,339	$ 77,018	$ 43,817
Net income (loss) attributable to AECOM per share:
Basic continuing operations per share	$ 0.19	$ 0.57	$ 1.35	$ 1.07
Basic discontinued operations per share	(0.11)	(0.01)	(0.83)	(0.79)
Basic earnings per share	0.08	0.56	0.52	0.28
Diluted continuing operations per share	0.19	0.56	1.32	1.06
Diluted discontinued operations per share	(0.11)	(0.01)	(0.81)	(0.79)
Diluted earnings per share	$ 0.08	$ 0.55	$ 0.51	$ 0.27
Weighted average shares outstanding:
Basic	146,109	160,119	148,434	158,667
Diluted	148,859	161,835	150,707	161,070

Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

No definition available.

Name:	acm_NetIncomeLossAttributableToRedeemableNoncontrollingInterestFromContinuingOperations
Namespace Prefix:	acm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate cost of goods produced and sold and services rendered during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=75031198&loc=d3e14064-108612

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(g)(1)(ii))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2)
-URI http://asc.fasb.org/extlink&oid=120395209&loc=SL114868664-224227

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571