Name:	acm_DebtInstrumentAdditionalPercentageOfIncreaseInAnnualInterestRateForEachSubsequentNinetyDayPeriodDuringWhichDefaultContinues
Namespace Prefix:	acm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of increase in annual interest rate when the debt is in default.

No definition available.

Name:	acm_DebtInstrumentPercentageOfIncreaseInInterestRateWhenDebtIsInDefault
Namespace Prefix:	acm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage price of original principal amount of debt, excluding required premium, at which debt can be redeemed by the issuer.

No definition available.

Name:	acm_DebtInstrumentRedemptionPricePercentageExcludingRequiredPremium
Namespace Prefix:	acm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the maximum additional interest rate per year when the debt is in default.

No definition available.

Name:	acm_MaximumAdditionalInterestRatePerYearWhenDebtIsInDefault
Namespace Prefix:	acm_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the maximum duration within which the registration statement relating to the registered exchange offer is required to be declared effective.

No definition available.

Name:	acm_MaximumDurationWithinWhichRegistrationStatementRelatingToRegisteredExchangeOffIsRequiredToBeDeclaredEffective
Namespace Prefix:	acm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the maximum duration within which the shelf registration statement relating to the resale of the Notes is required to be declared effective.

No definition available.

Name:	acm_MaximumDurationWithinWhichShelfRegistrationStatementRelatingToResaleOfNotesIsRequiredToBeDeclaredEffective
Namespace Prefix:	acm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the minimum period that the exchange offer is required to be kept open after the date notice of the exchange offer is mailed to the holders of the Notes.

No definition available.

Name:	acm_MaximumPeriodThatExchangeOfferIsRequiredToBeKeptOpenAfterDateNoticeOfExchangeOfferIsMailedToHoldersOfNotes
Namespace Prefix:	acm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the period during which additional percentage of increase in annual interest rate continues when the debt is in default.

No definition available.

Name:	acm_PeriodDuringWhichAdditionalPercentageOfIncreaseInAnnualInterestRateContinuesWhenDebtIsInDefault
Namespace Prefix:	acm_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 55

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Contractual interest rate for funds borrowed, under the debt agreement.

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(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

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.

No definition available.

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

End date of debt instrument redemption period, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 470

-Section 50

-Paragraph 3

-Subparagraph e

-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Name:	us-gaap_DebtInstrumentRedemptionPeriodEndDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

Start date of debt instrument redemption period, in CCYY-MM-DD format.

Name:	us-gaap_DebtInstrumentRedemptionPeriodStartDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

Name:	us-gaap_DebtInstrumentRedemptionPricePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of principal amount of debt redeemed.

No definition available.

Name:	us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.75Due2022AndSeniorNotes5.875Due2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.75Due2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.875Due2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: