Name:	acm_DebtInstrumentAdditionalPercentageOfIncreaseInAnnualInterestRateForEachSubsequentNinetyDayPeriodDuringWhichDefaultContinues
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Data Type:	num:percentItemType
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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
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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.

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Namespace Prefix:	acm_
Data Type:	xbrli:durationItemType
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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
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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

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

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
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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

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

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

Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.875Due2024Member
Namespace Prefix:
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Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
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Balance Type:
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Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.75Due2022AndSeniorNotes5.875Due2024Member
Namespace Prefix:
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Name:	us-gaap_DebtInstrumentAxis=acm_SeniorNotes5.75Due2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
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