XML 55 R38.htm IDEA: XBRL DOCUMENT v3.25.3

Pension Benefit Obligations (Tables)

12 Months Ended

Sep. 30, 2025

Retirement Benefits [Abstract]

Schedule of Reconciliations of Changes In the U.S. and International Plans' Benefit Obligations

The following tables provide reconciliations of the changes in the U.S. and international plans’ benefit obligations, reconciliations of the changes in the fair value of assets for the last three years ended September 30, and reconciliations of the funded status as of September 30 of each year.

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Change in benefit obligation:
Benefit obligation at beginning of year			$	186.9					$	860.4					$	181.2					$	756.2					$	198.1					$	791.2
Service cost			—						0.2						—						0.2						—						0.3
Participant contributions			0.1						0.2						0.1						0.3						0.1						0.2
Interest cost			7.9						40.1						9.7						43.7						9.8						47.7
Benefits and expenses paid			(17.1)						(46.2)						(17.6)						(47.7)						(17.2)						(42.2)
Actuarial loss (gain)			(0.2)						(69.8)						13.5						37.0						(8.8)						(112.5)
Plan settlements			(0.7)						—						—						(3.2)						(1.5)						(1.5)
Transfers in			—						—						—						—						0.7						—
Foreign currency translation loss			—						4.4						—						73.9						—						73.0
Benefit obligation at end of year			$	176.9					$	789.3					$	186.9					$	860.4					$	181.2					$	756.2

Schedule of Reconciliations of Changes In Fair Value of Assets

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Change in plan assets
Fair value of plan assets at beginning of year			$	109.0					$	804.3					$	98.8					$	673.3					$	101.4					$	683.5
Actual return on plan assets			3.0						(15.1)						15.8						89.0						7.8						(54.2)
Employer contributions			10.6						23.7						11.9						25.1						8.2						24.8
Participant contributions			0.1						0.2						0.1						0.3						0.1						0.2
Benefits and expenses paid			(17.1)						(46.2)						(17.6)						(47.7)						(17.2)						(42.2)
Plan settlements			(0.7)						—						—						(3.2)						(1.5)						(1.5)
Foreign currency translation gain			—						5.0						—						67.5						—						62.7
Fair value of plan assets at end of year			$	104.9					$	771.9					$	109.0					$	804.3					$	98.8					$	673.3

Schedule of Reconciliations of Funded Status

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Reconciliation of funded status:
Funded status at end of year			$	(72.0)					$	(17.4)					$	(77.9)					$	(56.1)					$	(82.4)					$	(82.9)
Contribution made after measurement date			N/A						N/A						N/A						N/A						N/A						N/A
Net amount recognized at end of year			$	(72.0)					$	(17.4)					$	(77.9)					$	(56.1)					$	(82.4)					$	(82.9)

Schedule of Amounts Recognized In the Consolidated Balance Sheets

The following table sets forth the amounts recognized in the consolidated balance sheets as of September 30, 2025, 2024 and 2023:

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Amounts recognized in the consolidated balance sheets:
Other non-current assets			$	—					$	52.3					$	—					$	46.6					$	—					$	38.7
Accrued expenses and other current liabilities			(8.5)						—						(8.3)						—						(8.4)						—
Pension benefit obligations			(63.5)						(69.7)						(69.6)						(102.7)						(74.0)						(121.6)
Net amount recognized in the balance sheet			$	(72.0)					$	(17.4)					$	(77.9)					$	(56.1)					$	(82.4)					$	(82.9)

Schedule of Reconciliation of Amounts In the Consolidated Statements of Stockholder's Equity

The following table details the reconciliation of amounts in the consolidated statements of stockholders’ equity for the fiscal years ended September 30, 2025, 2024 and 2023:

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Reconciliation of amounts in consolidated statements of stockholders’ equity:
Prior service cost			$	(0.1)					$	(1.2)					$	(0.1)					$	(1.3)					$	(0.1)					$	(1.2)
Net loss			(75.4)						(235.5)						(77.6)						(234.9)						(77.5)						(207.1)
Total recognized in accumulated other comprehensive loss			$	(75.5)					$	(236.7)					$	(77.7)					$	(236.2)					$	(77.6)					$	(208.3)

Schedule of Components of Net Periodic Cost

The following table details the components of net periodic benefit cost for the Company’s pension plans for fiscal years ended September 30, 2025, 2024 and 2023:

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Components of net periodic benefit cost:
Service costs			$	—					$	0.2					$	—					$	0.2					$	—					$	0.3
Interest cost on projected benefit obligation			7.9						40.1						9.7						43.7						9.8						47.7
Expected return on plan assets			(4.8)						(52.2)						(5.5)						(57.4)						(5.8)						(60.8)
Amortization of prior service costs			—						0.1						—						0.1						—						0.1
Amortization of net loss (gain)			3.7						(1.3)						3.1						(2.3)						3.5						(0.6)
Settlement loss (gain) recognized			0.1						—						—						0.1						(0.1)						0.2
Net periodic benefit cost (credit)			$	6.9					$	(13.1)					$	7.3					$	(15.6)					$	7.4					$	(13.1)

Schedule of Amounts Included In Accumulated Other Comprehensive Loss Expected to Be Recognized as Components of Net Periodic Benefit Cost

Amounts included in accumulated other comprehensive loss as of September 30, 2025 that are expected to be recognized as components of net periodic benefit cost during fiscal 2026 are (in millions):

			U.S.						Int’l
Amortization of prior service cost			$	—					$	(0.1)
Amortization of net actuarial (losses) gain			(3.8)						0.6
Total			$	(3.8)					$	0.5

Schedule of Additional Year-End Information for Pension Plans With Accumulated Benefit Obligations In Excess of Plan Assets

The table below provides additional year-end information for pension plans with accumulated benefit obligations in excess of plan assets.

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Projected benefit obligation			$	165.8					$	395.6					$	175.1					$	649.8					$	168.8					$	628.1
Accumulated benefit obligation			$	165.8					$	395.6					$	175.1					$	649.8					$	168.8					$	628.1
Fair value of plan assets			$	104.9					$	325.9					$	109.0					$	547.1					$	98.8					$	506.5

Schedule of Expected Future Benefit Payments

The table below provides the expected future benefit payments, in millions:

Year Ending September 30,						U.S.						Int’l
2026						$	26.8					$	52.2
2027						18.3						51.3
2028						17.6						52.9
2029						16.6						54.8
2030						15.7						56.0
2031-2035						66.0						297.5
Total						$	161.0					$	564.7

Schedule of Underlying Assumptions for Pension Plans

The underlying assumptions for the pension plans are as follows:

			Fiscal Year Ended
			September 30, 2025												September 30, 2024												September 30, 2023
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
			(in millions)
Weighted-average assumptions to determine benefit obligation:
Discount rate			5.01		%				5.83		%				4.73		%				5.04		%				5.76		%				5.65		%
Salary increase rate			N/A						2.81		%				N/A						2.91		%				N/A						3.06		%
Weighted-average assumptions to determine net periodic benefit cost:
Discount rate			4.73		%				5.04		%				5.76		%				5.65		%				5.40		%				5.27		%
Salary increase rate			N/A						2.91		%				N/A						3.06		%				N/A						3.48		%
Expected long-term rate of return on plan assets			6.25		%				5.51		%				6.90		%				5.74		%				7.00		%				6.04		%

Schedule of Target Allocation and Pension Plan Asset Allocation and Fair Values of Pension Plan Assets By Major Asset Categories

The following table summarizes the Company’s target allocation for 2025 and pension plan asset allocation, both U.S. and International, as of September 30, 2025 and 2024:

															Percentage of Plan Assets as of September 30,
			Target Allocations												2025												2024
			U.S.						Int’l						U.S.						Int’l						U.S.						Int’l
Asset Category:
Equities			18		%				25		%				19		%				24		%				24		%				25		%
Debt			78						65						74						64						67						64
Cash			—						3						2						2						4						2
Diversified and other			4						7						5						10						5						9
Total			100		%				100		%				100		%				100		%				100		%				100		%

As of September 30, 2025, the fair values of the Company’s pension plan assets by major asset categories were as follows:

									Fair Value Measurement as of September 30, 2025
			Total Carrying Value as of September 30, 2025						Quoted Prices in Active Markets (Level 1)						Significant Other Observable Inputs (Level 2)						Significant Unobservable Inputs (Level 3)						Investments measured at NAV
			(in millions)
Cash and cash equivalents			$	20.5					$	20.5					$	—					$	—					$	—
Debt securities			361.4						361.4						—						—						—
Investment funds:
Diversified and equity funds			272.5						71.5						14.1						—						186.9
Fixed income funds			220.5						22.7						4.4						—						193.4
Absolute return fund			5.1						—						—						—						5.1
Derivative instruments and other			(3.2)						9.9						(13.1)						—						—
Total			$	876.8					$	486.0					$	5.4					$	—					$	385.4

As of September 30, 2024, the fair values of the Company’s pension plan assets by major asset categories were as follows:

									Fair Value Measurement as of September 30, 2024
			Total Carrying Value as of September 30, 2024						Quoted Prices in Active Markets (Level 1)						Significant Other Observable Inputs (Level 2)						Significant Unobservable Inputs (Level 3)						Investments measured at NAV
			(in millions)
Cash and cash equivalents			$	22.1					$	22.1					$	—					$	—					$	—
Debt securities			391.5						391.5						—						—						—
Investment funds:
Diversified and equity funds			286.7						48.5						13.5						—						224.7
Fixed income funds			213.9						17.3						4.1						—						192.5
Absolute return fund			5.9						—						—						—						5.9
Derivative instruments and other			(6.8)						8.2						(15.0)						—						—
Total			$	913.3					$	487.6					$	2.6					$	—					$	423.1

X

- Definition

Tabular disclosure of net gain (loss), prior service cost (credit), and transition assets (obligations) included in accumulated other comprehensive income associated with a defined benefit pension or other postretirement plan(s) because they have yet to be recognized as components of net periodic benefit cost.

+ References

No definition available.

+ Details

Name:	acm_ScheduleOfAmountsRecognizedInConsolidatedStatementsOfStockholdersEquityTableTextBlock
Namespace Prefix:	acm_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

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

X

- Definition

Tabular disclosure of benefit obligation and plan assets of defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

+ Details

Name:	us-gaap_ScheduleOfAccumulatedBenefitObligationsInExcessOfFairValueOfPlanAssetsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the major categories of plan assets of pension plans and/or other employee benefit plans. This information may include, but is not limited to, the target allocation of plan assets, the fair value of each major category of plan assets, and the level within the fair value hierarchy in which the fair value measurements fall.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (d)(5)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the amounts related to pension plans and/or other employee benefit plans in accumulated other comprehensive income (loss) expected to be recognized as components of net periodic benefit cost over the next fiscal year, including the net gain (loss), net prior service cost or credit, and net transition asset or obligation.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfAmountsInAccumulatedOtherComprehensiveIncomeLossToBeRecognizedOverNextFiscalYearTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the amounts that are recognized in the balance sheet (or statement of financial position) for pension plans and/or other employee benefit plans, showing separately the assets and current and noncurrent liabilities (if applicable) recognized.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (g)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-5

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of assumption used to determine benefit obligation and net periodic benefit cost of defined benefit plan. Includes, but is not limited to, discount rate, rate of compensation increase, expected long-term rate of return on plan assets and interest crediting rate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (j)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (k)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfAssumptionsUsedTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the reconciliation of beginning and ending balances of the fair value of plan assets of pension plans and/or other employee benefit plans showing separately, if applicable, the effects during the period attributable to each of the following: actual return on plan assets, foreign currency exchange rate changes, contributions by the employer, contributions by plan participants, benefits paid, business combinations, divestitures, and settlements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (b)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfChangesInFairValueOfPlanAssetsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the change in the benefit obligation of pension plans and/or other employee benefit plans from the beginning to the end of the period, showing separately, if applicable, the effects of the following: service cost, interest cost, contributions by plan participants, actuarial gains and losses, foreign currency exchange rate changes, benefits paid, plan amendments, business combinations, divestitures, curtailments, settlements, and special and contractual termination benefits.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (a)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfChangesInProjectedBenefitObligationsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of benefits expected to be paid by pension plans and/or other employee benefit plans in each of the next five fiscal years and in the aggregate for the five fiscal years thereafter.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-5

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (f)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (q)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-5

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 715
-SubTopic 20
-Subparagraph (h)
-Name Accounting Standards Codification
-Paragraph 1
-Section 50
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfNetBenefitCostsTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Tabular disclosure of net funded status of pension plans and/or other employee benefit plans.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-1

+ Details

Name:	us-gaap_ScheduleOfNetFundedStatusTableTextBlock
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:textBlockItemType
Balance Type:	na
Period Type:	duration