The Number of years of capital commitments.

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Surety bonds issued primarily to support the Company's project execution and insurance program commitments.

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The amount of recovery from the refinery owner.

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Amount of damages paid to the plaintiff in the legal matter.

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Commitments and Contingencies (Details) - USD ($) $ in Millions		1 Months Ended		3 Months Ended	72 Months Ended
	Dec. 06, 2019	Dec. 31, 2019	Dec. 31, 2014	Dec. 31, 2019	Sep. 30, 2019	Dec. 12, 2019	Apr. 30, 2019	Mar. 31, 2019
AECOM USA, Inc.
Commitments and Contingencies
Consent order						$ 0.1
Department of Energy Deactivation, Demolition, And Removal Project \| Department of Energy \| Maximum
Commitments and Contingencies
Cost-reimbursement at risk		$ 106.0		$ 106.0
Department of Energy Deactivation, Demolition, And Removal Project \| AECOM E&C and DOE \| Minimum
Commitments and Contingencies
Cost-reimbursement at risk		106.0		106.0
Department of Energy Deactivation, Demolition, And Removal Project \| AECOM E&C and DOE \| Maximum
Commitments and Contingencies
Cost-reimbursement at risk		146.0		146.0
Department of Energy Deactivation, Demolition, And Removal Project \| AECOM E&C
Commitments and Contingencies
Claim to DOE, including additional fees	$ 60.4		$ 103.0
Possible costs which may exceed contracted amounts			$ 100.0
Department of Energy Deactivation, Demolition, And Removal Project \| AECOM E&C \| Minimum
Commitments and Contingencies
Cost-reimbursement at risk		146.0		146.0
Claim to DOE, including additional fees					$ 148.5
Department of Energy Deactivation, Demolition, And Removal Project \| AECOM E&C \| Maximum
Commitments and Contingencies
Claim to DOE, including additional fees					$ 329.4
Refinery Turnaround Project
Commitments and Contingencies
Damages paid, value		93.0
Refinery Turnaround Project \| AECOM E&C
Commitments and Contingencies
Damages claimed, value				144.0
Recoverable from refinery owner				90.0
Loss contingency, receivable amount							$ 132.0	$ 79.0
AECOM-Canyon Equity Fund, L.P
Commitments and Contingencies
Capital commitments				$ 35.0
Term of capital commitments				10 years
Standby letter of credit
Commitments and Contingencies
Contingency liability		$ 499.3		$ 499.3
Surety Bond
Commitments and Contingencies
Surety bonds issued				$ 4,800.0