This element represents loss contingency amount estimated recovery from third party

No definition available.

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

- Definition

Represents the estimated minimum cost to complete the project and promised amenities.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Represents the information pertaining to number of initial public offering investors.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of securities acquired by investors

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
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-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
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-Paragraph 20
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 16
-Article 9

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
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-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
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+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

The estimated maximum amount of possible loss from the contingency.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The estimated minimum amount of possible loss from the contingency.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of cash paid for the settlement of litigation or for other legal issues during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

+ Details

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- Definition

The cash inflow associated with the amount received from entity's first offering of stock to the public.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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Commitments and Contingencies (Details) CAD in Millions, AUD in Millions, $ in Millions			1 Months Ended		6 Months Ended	12 Months Ended
	Jul. 10, 2015 USD ($)	Jun. 17, 2014 AUD	Dec. 31, 2014 USD ($)	Jan. 31, 2010 CAD	Mar. 31, 2016 USD ($) item	Sep. 30, 2006 AUD
Commitments and Contingencies
Securities acquired by investors \| AUD		AUD 155
Standby Letters of Credit
Commitments and Contingencies
Contingency liability of general and professional liability insurance programs and for payment and performance guarantees					$ 484.3
DOE Deactivation Demolition And Removal Project \| URS Corporation \| Washington Group International
Commitments and Contingencies
Projects costs, maximum					146.0
DOE Deactivation Demolition And Removal Project \| Department of Energy
Commitments and Contingencies
Projects costs, minimum					106.0
DOE Deactivation Demolition And Removal Project \| Department of Energy \| URS Corporation \| Washington Group International
Commitments and Contingencies
Projects costs, minimum					106.0
Projects costs, maximum					$ 146.0
Amount recovery ( including additional Fees)			$ 103.0
Minimum cost to complete the project and promised amenities			$ 100.0
Canadian Pipeline Contract \| URS Corporation \| Flint Energy Services Ltd
Commitments and Contingencies
Damages claimed by applicants \| CAD				CAD 45
AECOM Australia
Commitments and Contingencies
Payments for Legal Settlements	$ 205.0
Proceeds from initial public offering (IPO) \| AUD						AUD 700
Bank loan \| AUD						AUD 1,400
Number of initial public offering investors \| item					770