XML 67 R46.htm IDEA: XBRL DOCUMENT
v3.24.3

Significant Accounting Policies - Fiscal Year (Details) | 12 Months Ended
--- | ---
Sep. 30, 2024 | Sep. 30, 2023 | Sep. 30, 2022
Significant Accounting Policies |  |  |
Length of fiscal year | 364 days | 364 days | 364 days
Minimum |  |  |
Significant Accounting Policies |  |  |
Length of fiscal year | 364 days |  |
Maximum |  |  |
Significant Accounting Policies |  |  |
Length of fiscal year | 371 days |  |

X
- 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
Name: | acm_SignificantAccountingPoliciesLineItems
Namespace Prefix: | acm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Duration of a fiscal period, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Includes, but not limited to, weeks in a year or quarter. + References No definition available. + Details
Name: | us-gaap_FiscalPeriodDuration
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |