AECOM (ACM) 10-K 17 Nov 14 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
In Billions, except Share data, unless otherwise specified	Sep. 30, 2014	Nov. 05, 2014	Mar. 28, 2014
Document and Entity Information	'	'	'
Entity Registrant Name	'AECOM TECHNOLOGY CORP	'	'
Entity Central Index Key	'0000868857	'	'
Document Type	'10-K	'	'
Document Period End Date	30-Sep-14	'	'
Amendment Flag	'false	'	'
Current Fiscal Year End Date	'--09-30	'	'
Entity Well-known Seasoned Issuer	'Yes	'	'
Entity Voluntary Filers	'No	'	'
Entity Current Reporting Status	'Yes	'	'
Entity Filer Category	'Large Accelerated Filer	'	'
Entity Public Float	'	'	$1.80
Entity Common Stock, Shares Outstanding	'	153,821,746	'
Document Fiscal Year Focus	'2014	'	'
Document Fiscal Period Focus	'FY	'	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2014	Sep. 30, 2013
In Thousands, unless otherwise specified
CURRENT ASSETS:	'	'
Cash and cash equivalents	$521,784	$450,328
Cash in consolidated joint ventures	52,404	150,349
Total cash and cash equivalents	574,188	600,677
Accounts receivable-net	2,654,976	2,342,262
Prepaid expenses and other current assets	177,536	168,714
Income taxes receivable	1,541	'
Deferred tax assets-net	25,872	19,949
TOTAL CURRENT ASSETS	3,434,113	3,131,602
PROPERTY AND EQUIPMENT-NET	281,979	270,672
DEFERRED TAX ASSETS-NET	118,038	143,478
INVESTMENTS IN UNCONSOLIDATED JOINT VENTURES	142,901	106,422
GOODWILL	1,937,338	1,811,754
INTANGIBLE ASSETS-NET	90,238	83,149
OTHER NON-CURRENT ASSETS	118,770	118,546
TOTAL ASSETS	6,123,377	5,665,623
CURRENT LIABILITIES:	'	'
Short-term debt	23,915	29,578
Accounts payable	1,047,155	725,389
Accrued expenses and other current liabilities	964,627	915,282
Income taxes payable	'	6,127
Billings in excess of costs on uncompleted contracts	379,574	322,486
Current portion of long-term debt	40,498	54,687
TOTAL CURRENT LIABILITIES	2,455,769	2,053,549
OTHER LONG-TERM LIABILITIES	455,563	448,920
LONG-TERM DEBT	939,565	1,089,060
TOTAL LIABILITIES	3,850,897	3,591,529
COMMITMENTS AND CONTINGENCIES (Note 20)	'	'
AECOM STOCKHOLDERS' EQUITY:	'	'
Common stock-authorized, 300,000,000 shares of $0.01 par value as of September 30, 2014 and 2013; issued and outstanding 96,715,797 and 96,016,358 shares as of September 30, 2014 and 2013, respectively	967	960
Additional paid-in capital	1,864,971	1,809,627
Accumulated other comprehensive loss	-356,602	-261,299
Retained earnings	677,181	472,155
TOTAL AECOM STOCKHOLDERS' EQUITY	2,186,517	2,021,443
Noncontrolling interests	85,963	52,651
TOTAL STOCKHOLDERS' EQUITY	2,272,480	2,074,094
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$6,123,377	$5,665,623

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2014	Sep. 30, 2013
Statement of Financial Position [Abstract]	'	'
Common stock, authorized shares	300,000,000	300,000,000
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, issued shares	96,715,797	96,016,358
Common stock, outstanding shares	96,715,797	96,016,358

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Statement [Abstract]	'	'	'	'	'	'	'	'	'	'	'
Revenue	$2,562,500	$1,968,200	$1,872,200	$1,953,900	$2,079,100	$2,067,500	$1,989,600	$2,017,300	$8,356,783	$8,153,495	$8,218,180
Cost of revenue.	2,433,400	1,859,700	1,784,800	1,875,700	1,938,900	1,935,700	1,889,700	1,939,200	7,953,607	7,703,507	7,796,321
Gross profit	129,100	108,500	87,400	78,200	140,200	131,800	99,900	78,100	403,176	449,988	421,859
Equity in earnings of joint ventures	8,400	6,000	7,400	36,100	6,400	4,100	7,900	5,900	57,924	24,319	48,650
General and administrative expenses	-15,500	-15,100	-26,400	-23,900	-23,900	-24,000	-27,300	-22,100	-80,908	-97,318	-80,903
Acquisition and integration expense	19,500	7,800	'	'	'	'	'	'	-27,310	'	'
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	-336,000
Income from operations	102,500	91,600	68,400	90,400	122,700	111,900	80,500	61,900	352,882	376,989	53,606
Other income	1,900	1,000	-200	'	1,500	1,200	100	700	2,748	3,522	10,603
Interest expense	-10,100	-9,800	-10,500	-10,400	-10,200	-11,700	-11,900	-10,900	-40,842	-44,737	-46,726
Income before income tax expense	94,300	82,800	57,700	80,000	114,000	101,400	68,700	51,700	314,788	335,774	17,483
Income tax expense	29,600	13,700	15,200	23,500	35,800	30,100	14,000	12,700	82,024	92,578	74,416
Net income (loss)	64,700	69,100	42,500	56,500	78,200	71,300	54,700	39,000	232,764	243,196	-56,933
Noncontrolling interests in income of consolidated subsidiaries, net of tax	-600	100	-2,300	-100	-1,700	-500	-900	-900	-2,910	-3,953	-1,634
Net income (loss) attributable to AECOM	$64,100	$69,200	$40,200	$56,400	$76,500	$70,800	$53,800	$38,100	$229,854	$239,243	($58,567)
Net income (loss) attributable to AECOM per share:	'	'	'	'	'	'	'	'	'	'	'
Basic (in dollars per share)	$0.65	$0.71	$0.41	$0.59	$0.78	$0.71	$0.54	$0.36	$2.36	$2.38	($0.52)
Diluted (in dollars per share)	$0.64	$0.70	$0.41	$0.58	$0.77	$0.70	$0.53	$0.36	$2.33	$2.35	($0.52)
Weighted average shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic (in shares)	98,100	97,500	97,000	96,300	98,000	99,300	100,400	104,800	97,226	100,618	111,875
Diluted (in shares)	99,700	99,000	98,300	97,600	99,700	100,800	101,800	105,500	98,657	101,942	111,875

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]	'	'	'
Net income (loss)	$232,764	$243,196	($56,933)
Other comprehensive income (loss), net of tax:	'	'	'
Net unrealized gain (loss) on derivatives, net of tax	315	1,568	-3,716
Foreign currency translation adjustments	-72,715	-70,441	53,895
Pension adjustments, net of tax	-24,161	-14,582	-41,778
Other comprehensive income (loss), net of tax	-96,561	-83,455	8,401
Comprehensive income (loss), net of tax	136,203	159,741	-48,532
Noncontrolling interests in comprehensive income of consolidated subsidiaries, net of tax	-1,652	-2,624	-1,634
Comprehensive income (loss) attributable to AECOM, net of tax	$134,551	$157,117	($50,166)

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Parent [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Total
In Thousands, unless otherwise specified
BALANCE at Sep. 30, 2011	$2,339,711	$1,132	$1,699,207	($187,574)	$826,946	$55,426	$2,395,137
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'
Net income (loss)	-58,567	'	'	'	-58,567	1,634	-56,933
Other comprehensive income (loss)	8,401	'	'	8,401	'	'	8,401
Issuance of stock	18,631	9	18,622	'	'	'	18,631
Repurchases of stock	-169,454	-83	-7,081	'	-162,290	'	-169,454
Proceeds from exercise of options	4,541	4	4,537	'	'	'	4,541
Tax benefit from exercise of stock options	-350	'	-350	'	'	'	-350
Stock based compensation	26,551	8	26,543	'	'	'	26,551
Other transactions with noncontrolling interests	'	'	'	'	'	-753	-753
Distributions to noncontrolling interests	'	'	'	'	'	-1,283	-1,283
BALANCE at Sep. 30, 2012	2,169,464	1,070	1,741,478	-179,173	606,089	55,024	2,224,488
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'
Net income (loss)	239,243	'	'	'	239,243	3,953	243,196
Other comprehensive income (loss)	-82,126	'	'	-82,126	'	-1,329	-83,455
Issuance of stock	28,351	11	28,340	'	'	'	28,351
Repurchases of stock	-381,704	-147	-8,380	'	-373,177	'	-381,704
Proceeds from exercise of options	14,365	8	14,357	'	'	'	14,365
Tax benefit from exercise of stock options	1,239	'	1,239	'	'	'	1,239
Stock based compensation	32,611	18	32,593	'	'	'	32,611
Other transactions with noncontrolling interests	'	'	'	'	'	13,488	13,488
Contributions from noncontrolling interests	'	'	'	'	'	1,421	1,421
Distributions to noncontrolling interests	'	'	'	'	'	-19,906	-19,906
BALANCE at Sep. 30, 2013	2,021,443	960	1,809,627	-261,299	472,155	52,651	2,074,094
Increase (Decrease) in Stockholders' Equity	'	'	'	'	'	'	'
Net income (loss)	229,854	'	'	'	229,854	2,910	232,764
Other comprehensive income (loss)	-95,303	'	'	-95,303	'	-1,258	-96,561
Issuance of stock	13,886	4	13,882	'	'	'	13,886
Repurchases of stock	-31,620	-14	-6,778	'	-24,828	'	-31,620
Proceeds from exercise of options	13,417	6	13,411	'	'	'	13,417
Tax benefit from exercise of stock options	402	'	402	'	'	'	402
Stock based compensation	34,438	11	34,427	'	'	'	34,438
Other transactions with noncontrolling interests	'	'	'	'	'	61,913	61,913
Distributions to noncontrolling interests	'	'	'	'	'	-30,253	-30,253
BALANCE at Sep. 30, 2014	$2,186,517	$967	$1,864,971	($356,602)	$677,181	$85,963	$2,272,480

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:	'	'	'
Net income (loss)	$232,764	$243,196	($56,933)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'	'
Depreciation and amortization	95,394	94,406	102,974
Equity in earnings of unconsolidated joint ventures	-57,924	-24,319	-48,650
Distribution of earnings from unconsolidated joint ventures	23,839	31,159	26,401
Non-cash stock compensation	34,438	32,611	26,551
Excess tax benefit from share-based payment	-748	-1,754	-1,254
Foreign currency translation	-20,794	-16,061	9,735
Deferred income tax expense (benefit)	27,155	-7,210	-20,303
Goodwill impairment	'	'	336,000
Other	1,460	1,821	-5,286
Changes in operating assets and liabilities, net of effects of acquisitions:	'	'	'
Accounts receivable	-14,405	92,152	-21,544
Prepaid expenses and other assets	-31,103	-21,836	11,363
Accounts payable	91,955	-47,019	80,999
Accrued expenses and other current liabilities	3,283	71,125	14,682
Billings in excess of costs on uncompleted contracts	3,095	-12,945	-5,376
Other long-term liabilities	-23,702	-19,027	-28,180
Income taxes payable	-4,082	-7,701	12,173
Net cash provided by operating activities	360,625	408,598	433,352
CASH FLOWS FROM INVESTING ACTIVITIES:	'	'	'
Payments for business acquisitions, net of cash acquired	-53,099	-42,005	-12,571
Cash acquired from consolidation of joint venture	18,955	'	'
Proceeds from disposal of businesses and property	3,646	2,724	2,647
Net investment in unconsolidated joint ventures	-52,173	-23,822	-2,846
Sales (purchases) of investments	2,727	-24,270	1,871
Payments for capital expenditures	-62,852	-52,117	-62,874
Net cash used in investing activities	-142,796	-139,490	-73,773
CASH FLOWS FROM FINANCING ACTIVITIES:	'	'	'
Proceeds from borrowings under credit agreements	1,810,318	2,280,080	1,454,861
Repayments of borrowings under credit agreements	-1,998,882	-2,156,399	-1,550,996
Cash paid for debt issuance costs	-8,067	-1,616	'
Proceeds from issuance of common stock	13,886	14,029	13,760
Proceeds from exercise of stock options	13,417	14,365	4,541
Payments to repurchase common stock under the Repurchase Program	-34,924	-388,101	-159,751
Excess tax benefit from share-based payment	748	1,754	1,254
Net distributions to noncontrolling interests	-30,253	-18,485	-1,283
Net cash used in financing activities	-233,757	-254,373	-237,614
EFFECT OF EXCHANGE RATE CHANGES ON CASH	-10,561	-7,834	14,871
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	-26,489	6,901	136,836
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	600,677	593,776	456,940
CASH AND CASH EQUIVALENTS AT END OF YEAR	574,188	600,677	593,776
SUPPLEMENTAL CASH FLOW INFORMATION:	'	'	'
Equity issued for acquisitions (non-cash)	'	14,322	857
Equity issued to settle liabilities (non-cash)	'	'	4,016
Interest paid	43,362	37,342	39,044
Income taxes paid, net of refunds received	$68,797	$115,508	$38,482

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Sep. 30, 2014
Significant Accounting Policies	'
Significant Accounting Policies	'
	1. Significant Accounting Policies
	Organization—AECOM Technology Corporation and its consolidated subsidiaries (the Company) provide professional technical and management support services for commercial and government clients around the world. These services encompass a variety of technical disciplines, including consulting, planning, architectural and engineering design, and program and construction management for a broad range of projects. These services are applied to a number of areas and industries, including transportation infrastructure; research, testing and defense facilities; water, wastewater and other environmental programs; land development; security and communication systems; institutional, mining, industrial and commercial and energy-related facilities. The Company also provides operations and maintenance services to governmental agencies throughout the U.S. and abroad.
	Fiscal Year—The Company reports results of operations based on 52 or 53-week periods ending on the Friday nearest September 30. For clarity of presentation, all periods are presented as if the year ended on September 30. Fiscal years 2014, 2013 and 2012 contained 53, 52 and 52 weeks, respectively, and ended on October 3, September 27, and September 28, respectively.
	Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the United States (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The more significant estimates affecting amounts reported in the consolidated financial statements relate to revenues under long-term contracts and self-insurance accruals. Actual results could differ from those estimates.
	Principles of Consolidation and Presentation—The consolidated financial statements include the accounts of all majority-owned subsidiaries and material joint ventures in which the Company is the primary beneficiary. All inter-company accounts have been eliminated in consolidation. Also see Note 7 regarding joint ventures and variable interest entities.
	Revenue Recognition—The Company generally utilizes a cost-to-cost approach in applying the percentage-of-completion method of revenue recognition. Under this approach, revenue is earned in proportion to total costs incurred, divided by total costs expected to be incurred. Recognition of revenue and profit is dependent upon a number of factors, including the accuracy of a variety of estimates made at the balance sheet date, engineering progress, materials quantities, the achievement of milestones, penalty provisions, labor productivity and cost estimates made at the balance sheet date. Due to uncertainties inherent in the estimation process, actual completion costs may vary from estimates. If estimated total costs on contracts indicate a loss, the Company recognizes that estimated loss in the period the estimated loss first becomes known.
	In the course of providing its services, the Company routinely subcontracts for services and incurs other direct costs on behalf of its clients. These costs are passed through to clients and, in accordance with industry practice and GAAP, are included in the Company's revenue and cost of revenue. Because subcontractor services and other direct costs can change significantly from project to project and period to period, changes in revenue may not be indicative of business trends. These other direct costs for the years ended September 30, 2014, 2013 and 2012 were $3.5 billion, $3.2 billion and $3.0 billion, respectively.
	Cost-Plus Contracts.    The Company enters into two major types of cost-plus contracts:
	Cost-Plus Fixed Fee.    Under cost-plus fixed fee contracts, the Company charges clients for its costs, including both direct and indirect costs, plus a fixed negotiated fee. The total estimated cost plus the fixed negotiated fee represents the total contract value. The Company recognizes revenue based on the actual labor and other direct costs incurred, plus the portion of the fixed fee it has earned to date.
	Cost-Plus Fixed Rate.    Under the Company's cost-plus fixed rate contracts, the Company charges clients for its direct and indirect costs based upon a negotiated rate. The Company recognizes revenue based on the actual total costs it has expended and the applicable fixed rate.
	Certain cost-plus contracts provide for award fees or a penalty based on performance criteria in lieu of a fixed fee or fixed rate. Other contracts include a base fee component plus a performance-based award fee. In addition, the Company may share award fees with subcontractors. The Company records accruals for fee-sharing as fees are earned. The Company generally recognizes revenue to the extent of costs actually incurred plus a proportionate amount of the fee expected to be earned. The Company takes the award fee or penalty on contracts into consideration when estimating revenue and profit rates, and it records revenue related to the award fees when there is sufficient information to assess anticipated contract performance. On contracts that represent higher than normal risk or technical difficulty, the Company may defer all award fees until an award fee letter is received. Once an award fee letter is received, the estimated or accrued fees are adjusted to the actual award amount.
	Certain cost-plus contracts provide for incentive fees based on performance against contractual milestones. The amount of the incentive fees varies, depending on whether the Company achieves above, at, or below target results. The Company originally recognizes revenue on these contracts based upon expected results. These estimates are revised when necessary based upon additional information that becomes available as the contract progresses.
	Time-and-Materials Contracts.
	Time-and-Materials.    Under time-and-materials contracts, the Company negotiates hourly billing rates and charges its clients based on the actual time that it expends on a project. In addition, clients reimburse the Company for its actual out-of-pocket costs of materials and other direct incidental expenditures that it incurs in connection with its performance under the contract. Profit margins on time-and-materials contracts fluctuate based on actual labor and overhead costs that it directly charges or allocates to contracts compared to negotiated billing rates. Many of the Company's time-and-materials contracts are subject to maximum contract values and, accordingly, revenue relating to these contracts is recognized as if these contracts were a fixed-price contract.
	Fixed-Price Contracts.
	Fixed-Price.    Fixed-price contracting is the predominant contracting method outside of the United States. There are typically two types of fixed-price contracts. The first and more common type, lump-sum, involves performing all of the work under the contract for a specified lump-sum fee. Lump-sum contracts are typically subject to price adjustments if the scope of the project changes or unforeseen conditions arise. The second type, fixed-unit price, involves performing an estimated number of units of work at an agreed price per unit, with the total payment under the contract determined by the actual number of units delivered. The Company recognizes revenue on fixed-price contracts using the percentage-of-completion method described above. Prior to completion, recognized profit margins on any fixed-price contract depend on the accuracy of the Company's estimates and will increase to the extent that its actual costs are below the estimated amounts. Conversely, if the Company's costs exceed these estimates, its profit margins will decrease and the Company may realize a loss on a project. The Company recognizes anticipated losses on contracts in the period in which they become evident.
	Service-Related Contracts.
	Service-Related.    Service-related contracts, including operations and maintenance services and a variety of technical assistance services, are accounted for over the period of performance, in proportion to the costs of performance.
	Contract Claims—Claims are amounts in excess of the agreed contract price (or amounts not included in the original contract price) that the Company seeks to collect from customers or others for delays, errors in specifications and designs, contract terminations, change orders in dispute or unapproved as to both scope and price or other causes of unanticipated additional costs. The Company records contract revenue related to claims only if it is probable that the claim will result in additional contract revenue and if the amount can be reliably estimated. In such cases, the Company records revenue only to the extent that contract costs relating to the claim have been incurred. As of September 30, 2014 and 2013, the Company had no significant net receivables related to contract claims.
	Government Contract Matters—The Company's federal government and certain state and local agency contracts are subject to, among other regulations, regulations issued under the Federal Acquisition Regulations (FAR). These regulations can limit the recovery of certain specified indirect costs on contracts and subjects the Company to ongoing multiple audits by government agencies such as the Defense Contract Audit Agency (DCAA). In addition, most of the Company's federal and state and local contracts are subject to termination at the discretion of the client.
	Audits by the DCAA and other agencies consist of reviews of the Company's overhead rates, operating systems and cost proposals to ensure that the Company accounted for such costs in accordance with the Cost Accounting Standards of the FAR (CAS). If the DCAA determines the Company has not accounted for such costs consistent with CAS, the DCAA may disallow these costs. There can be no assurance that audits by the DCAA or other governmental agencies will not result in material cost disallowances in the future.
	Cash and Cash Equivalents—The Company's cash equivalents include highly liquid investments which have an initial maturity of three months or less.
	Allowance for Doubtful Accounts—The Company records its accounts receivable net of an allowance for doubtful accounts. This allowance for doubtful accounts is estimated based on management's evaluation of the contracts involved and the financial condition of its clients. The factors the Company considers in its contract evaluations include, but are not limited to:
	•	Client type—federal or state and local government or commercial client;
	•	Historical contract performance;
	•		Historical collection and delinquency trends;
	•		Client credit worthiness; and
	•		General economic conditions.
	Derivative Financial Instruments—The Company accounts for its derivative instruments as either assets or liabilities and carries them at fair value.
	For derivative instruments that hedge the exposure to variability in expected future cash flows that are designated as cash flow hedges, the effective portion of the gain or loss on the derivative instrument is reported as a component of accumulated other comprehensive income in stockholders' equity and reclassified into income in the same period or periods during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument, if any, is recognized in current income. To receive hedge accounting treatment, cash flow hedges must be highly effective in offsetting changes to expected future cash flows on hedged transactions.
	The net gain or loss on the effective portion of a derivative instrument that is designated as an economic hedge of the foreign currency translation exposure generated by the re-measurement of certain assets and liabilities denominated in a non-functional currency in a foreign operation is reported in the same manner as a foreign currency translation adjustment. Accordingly, any gains or losses related to these derivative instruments are recognized in current income.
	Derivatives that do not qualify as hedges are adjusted to fair value through current income.
	Fair Value of Financial Instruments—The Company determines the fair values of its financial instruments, including short-term investments, debt instruments and derivative instruments, and pension and post-retirement plan assets based on inputs or assumptions that market participants would use in pricing an asset or a liability. The Company categorizes its instruments using a valuation hierarchy for disclosure of the inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; Level 3 inputs are unobservable inputs based on the Company's assumptions used to measure assets and liabilities at fair value. The classification of a financial asset or liability within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short maturities of these instruments. The carrying amount of the revolving credit facility approximates fair value because the interest rates are based upon variable reference rates. See also Notes 9 and 11.
	The Company's fair value measurement methods may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Although the Company believes its valuation methods are appropriate and consistent with those used by other market participants, the use of different methodologies or assumptions to determine fair value could result in a different fair value measurement at the reporting date.
	Property and Equipment—Property and equipment are recorded at cost and are depreciated over their estimated useful lives using the straight-line method. Expenditures for maintenance and repairs are expensed as incurred. Typically, estimated useful lives range from three to ten years for equipment, furniture and fixtures. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the remaining terms of the underlying lease agreement.
	Long-lived Assets—Long-lived assets to be held and used are reviewed for impairment whenever events or circumstances indicate that the assets may be impaired. For assets to be held and used, impairment losses are recognized based upon the excess of the asset's carrying amount over the fair value of the asset. For long-lived assets to be disposed, impairment losses are recognized at the lower of the carrying amount or fair value less cost to sell.
	Goodwill and Acquired Intangible Assets—Goodwill represents the excess of amounts paid over the fair value of net assets acquired from an acquisition. In order to determine the amount of goodwill resulting from an acquisition, the Company performs an assessment to determine the value of the acquired company's tangible and identifiable intangible assets and liabilities. In its assessment, the Company determines whether identifiable intangible assets exist, which typically include backlog and customer relationships. Intangible assets are amortized over the period in which the contractual or economic benefits of the intangible assets are expected to be realized.
	The Company tests goodwill for impairment annually for each reporting unit in the fourth quarter of the fiscal year, and between annual tests if events occur or circumstances change which suggest that goodwill should be evaluated. Such events or circumstances include significant changes in legal factors and business climate, recent losses at a reporting unit, and industry trends, among other factors. A reporting unit is defined as an operating segment or one level below an operating segment. The Company's impairment tests are performed at the operating segment level as they represent the Company's reporting units.
	The impairment test is a two-step process. During the first step, the Company estimates the fair value of the reporting unit using income and market approaches, and compares that amount to the carrying value of that reporting unit. In the event the fair value of the reporting unit is determined to be less than the carrying value, a second step is required. The second step requires the Company to perform a hypothetical purchase allocation for that reporting unit and to compare the resulting current implied fair value of the goodwill to the current carrying value of the goodwill for that reporting unit. In the event that the current implied fair value of the goodwill is less than the carrying value, an impairment charge is recognized. See also Note 4.
	Pension Plans—The Company has certain defined benefit pension plans. The Company calculates the market-related value of assets, which is used to determine the return-on-assets component of annual pension expense and the cumulative net unrecognized gain or loss subject to amortization. This calculation reflects the Company's anticipated long-term rate of return and amortization of the difference between the actual return (including capital, dividends, and interest) and the expected return over a five-year period. Cumulative net unrecognized gains or losses that exceed 10% of the greater of the projected benefit obligation or the market related value of plan assets are subject to amortization.
	Insurance Reserves—The Company maintains insurance for certain insurable business risks. Insurance coverage contains various retention and deductible amounts for which the Company accrues a liability based upon reported claims and an actuarially determined estimated liability for certain claims incurred but not reported. It is the Company's policy not to accrue for any potential legal expense to be incurred in defending the Company's position. The Company believes that its accruals for estimated liabilities associated with professional and other liabilities are sufficient and any excess liability beyond the accrual is not expected to have a material adverse effect on the Company's results of operations or financial position.
	Foreign Currency Translation—The Company's functional currency is the U.S. dollar. Results of operations for foreign entities are translated to U.S. dollars using the average exchange rates during the period. Assets and liabilities for foreign entities are translated using the exchange rates in effect as of the date of the balance sheet. Resulting translation adjustments are recorded as a foreign currency translation adjustment into other accumulated comprehensive income/(loss) in stockholders' equity.
	The Company uses foreign currency forward contracts from time to time to mitigate foreign currency risk. The Company limits exposure to foreign currency fluctuations in most of its contracts through provisions that require client payments in currencies corresponding to the currency in which costs are incurred. As a result of this natural hedge, the Company generally does not need to hedge foreign currency cash flows for contract work performed. The functional currency of all significant foreign operations is the respective local currency.
	Noncontrolling interests— Noncontrolling interests represent the equity investments of the minority owners in our joint ventures and other subsidiary entities that we consolidate in our financial statements.
	Income Taxes—The Company files a consolidated federal income tax return and combined / consolidated state tax returns and separate company state tax returns. The Company accounts for certain income and expense items differently for financial reporting and income tax purposes. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities, applying enacted statutory tax rates in effect for the year in which the differences are expected to reverse. In determining the need for a valuation allowance, management reviews both positive and negative evidence, including the nature, frequency, and severity of cumulative financial reporting losses in recent years, the future reversal of existing temporary differences, predictability of future taxable income exclusive of reversing temporary differences of the character necessary to realize the asset, relevant carry forward periods, taxable income in carry-back years if carry-back is permitted under tax law, and prudent and feasible tax planning strategies that would be implemented, if necessary, to protect against the loss of the deferred tax asset. Based upon management's assessment of all available evidence, the Company has concluded that it is more likely than not that the deferred tax assets, net of valuation allowance, will be realized.
	In July 2013, the FASB issued new accounting guidance that requires the presentation of unrecognized tax benefits as a reduction of the deferred tax assets, when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. This new guidance was effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. This guidance is effective for the Company's fiscal year beginning October 1, 2014 and it is not expected to have a material impact on the Company's consolidated financial statements.
	Acquisition and Integration Expenses—Acquisition and integration expenses are comprised of transaction costs, professional fees, and personnel costs, including due diligence and integration activities, primarily related to the acquisition of URS Corporation (Note 24).

New_Accounting_Pronouncements_

New Accounting Pronouncements and Changes in Accounting	12 Months Ended
	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting	'
New Accounting Pronouncements and Changes in Accounting	'
	2. New Accounting Pronouncements and Changes in Accounting
	In February 2013, the Financial Accounting Standards Board (FASB) issued new accounting guidance to update the presentation of reclassifications from comprehensive income to net income in consolidated financial statements. Under this new guidance, an entity is required to present information about the amounts reclassified out of accumulated other comprehensive income either by the respective line items of net income or by cross-reference to other required disclosures. The new guidance does not change the requirements for reporting net income or other comprehensive income in financial statements. This guidance was effective for the Company's fiscal year beginning October 1, 2013 and did not have a material impact on the Company's consolidated financial statements.
	In February 2013, the FASB issued new accounting guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for which the total amount of the obligation (within the scope of this guidance) is fixed at the reporting date. Examples of obligations within the scope of this guidance include debt arrangements, other contractual obligations, and settled litigation and judicial rulings. This new guidance was effective for annual reporting periods beginning after December 15, 2013 and subsequent interim periods. This guidance is effective for the Company's fiscal year beginning October 1, 2014 and it is not expected to have a material impact on the Company's consolidated financial statements.
	In July 2013, the FASB issued new accounting guidance that requires the presentation of unrecognized tax benefits as a reduction of the deferred tax assets, when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. This new guidance was effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. This guidance is effective for the Company's fiscal year beginning October 1, 2014 and it is not expected to have a material impact on the Company's consolidated financial statements.
	In May 2014, the FASB issued new accounting guidance which amended the existing accounting standards for revenue recognition. The new accounting guidance establishes principles for recognizing revenue upon the transfer of promised goods or services to customers, in an amount that reflects the expected consideration received in exchange for those goods or services. This guidance is effective for the Company's fiscal year beginning October 1, 2017. Early adoption is not permitted. The amendments may be applied retrospectively to each prior period presented or retrospectively with the cumulative effect recognized as of the date of initial application. The Company has not selected a transition method and is currently in the process of evaluating the impact of adoption of the new accounting guidance on its consolidated financial statements.

Stock_Repurchase_Program

Stock Repurchase Program	12 Months Ended
	Sep. 30, 2014
Stock Repurchase Program	'
Stock Repurchase Program	'
	3. Stock Repurchase Program
	The Company's Board of Directors has authorized the repurchase of up to $1.0 billion in Company stock. Share repurchases can be made through open market purchases or other methods, including pursuant to a Rule 10b5-1 plan. From the inception of the stock repurchase program, the Company has purchased a total of 27.4 million shares at an average price of $24.10 per share, for a total cost of $660.1 million as of September 30, 2014.

Business_Acquisitions_Goodwill

Business Acquisitions, Goodwill and Intangible Assets	12 Months Ended
	Sep. 30, 2014
Business Acquisitions, Goodwill, and Intangible Assets	'
Business Acquisitions, Goodwill, and Intangible Assets	'
	4. Business Acquisitions, Goodwill, and Intangible Assets
	The Company completed two, two and one business acquisitions during the years ended September 30, 2014, 2013 and 2012, respectively. Business acquisitions completed during the years ended September 30, 2014, 2013 and 2012 did not meet the quantitative thresholds to require pro forma disclosures of operating results, either individually or in the aggregate, based on the Company's consolidated assets, investments and net income. The Company also obtained control of an unconsolidated joint venture that resulted in its consolidation during the year ended September 30, 2014, as further discussed in Note 7.
	Business acquisitions during the year ended September 30, 2014 included Hunt Construction Group, a United States-based commercial construction management firm which serves clients in both the public and private sectors, and Spain-based ACE International Consultants S.L., a leading consulting firm specializing in economic and social development cooperation and private sector development.
	Business acquisitions during the year ended September 30, 2013 included South Africa-based BKS Group and Asia-based KPK Quantity Surveyors.
	During the year ended September 30, 2012, the Company acquired an environmental engineering firm in Asia.
	The aggregate value of all consideration for acquisitions consummated during the years ended September 30, 2014, 2013 and 2012 were $88.5 million, $82.0 million and $15.4 million, respectively. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed, as of the acquisition dates, from acquisitions consummated during the fiscal years presented:
			Fiscal Year Ended
			September 30,			September 30,			September 30,
			2014			2013			2012
			(in millions)
	Cash acquired		$	17.1		$	20.1		$	1.9
	Other current assets			256.2			41.5			7.8
	Goodwill			72.7			72.6			10.5
	Intangible assets			11.9			9.4			1.5
	Other non-current assets			16.5			8.6			3.3
	Current liabilities			(274.1	)		(54.9	)		(8.8	)
	Non-current liabilities			(11.8	)		(15.3	)		(0.8	)
	Net assets acquired		$	88.5		$	82		$	15.4
	Acquired intangible assets above includes the following:
			Fiscal Year Ended
			September 30,			September 30,			September 30,
			2014			2013			2012
			(in millions)
	Backlog		$	5.8		$	4.2		$	0.7
	Customer relationships			4.6			5.2			0.8
	Trademark / tradename			1.5			—			—
	Total intangible assets		$	11.9		$	9.4		$	1.5
	Consideration for acquisitions above includes the following:
			Fiscal Year Ended
			September 30,			September 30,			September 30,
			2014			2013			2012
			(in millions)
	Cash paid		$	70.2		$	62.1		$	14.5
	Promissory notes			18.3			5.6			—
	Equity issued			—			14.3			0.9
	Total consideration		$	88.5		$	82.0		$	15.4
	All of the above acquisitions were accounted for under the purchase method of accounting. As such, the purchase consideration of each acquired company was allocated to acquired tangible and intangible assets and liabilities based upon their fair values. The final purchase price allocation has not been completed for acquisitions made during the year ended September 30, 2014. The excess of the purchase consideration over the fair value of the net tangible and identifiable intangible assets acquired was recorded as goodwill. The determination of fair values of assets and liabilities acquired requires the Company to make estimates and use valuation techniques when market value is not readily available.  The results of operations of each company acquired have been included in the Company's financial statements from the date of acquisition. Transaction costs associated with business acquisitions are expensed as they are incurred.
	At the time of acquisition, the Company preliminarily estimates the amount of the identifiable intangible assets acquired based upon historical valuations of similar acquisitions and the facts and circumstances available at the time. The Company determines the final value of the identifiable intangible assets as soon as information is available, but not more than 12 months from the date of acquisition. Post-acquisition adjustments primarily relate to project related liabilities.
	During the fourth quarter of its fiscal year, the Company conducts its annual goodwill impairment test. The impairment evaluation process includes, among other things, making assumptions about variables such as revenue growth rates, profitability, discount rates, and industry market multiples, which are subject to a high degree of judgment.
	As a result of the first step of the fiscal 2012 impairment analysis, the Company identified adverse market conditions and business trends within the Europe, Middle East, and Africa (EMEA) and MSS reporting units, which led the Company to determine that goodwill was impaired. Adverse market conditions included prolonged and sustained deterioration of European macroeconomic conditions in EMEA and decreased U.S. government military activities and unsuccessful contract pursuits in MSS. The reporting units' goodwill impairments largely relate to the following acquired businesses:
	•	MSS—McNeil Technologies, Inc.
	•	EMEA—Davis Langdon Europe and Middle East
	Significant changes to the assumptions used in the September 30, 2012 as compared to the September 30, 2011 analysis were financial forecasts and market multiples. While both the MSS and the EMEA reporting units have historically generated positive cash flows, and are expected to continue to generate positive cash flows, the fair value of future cash flows of the Company's EMEA and MSS reporting units decreased. Additionally, the market multiples for the two reporting units decreased. The market multiples used were as follows:
			September 30,
			2012			2011
	Market multiple of revenue:
	EMEA			0.35			0.5
	MSS			0.35			0.5
	The second step of the analysis was performed to measure the impairment as the excess of the goodwill carrying value over its implied fair value. This analysis resulted in an impairment of $336.0 million, or $317.2 million, net of tax. The goodwill carrying values of the EMEA and MSS reporting units before and after the goodwill impairment expense were as follows:
			September 30, 2012
			EMEA			MSS
	Carrying value before impairment		$	345.5		$	347.8
	Goodwill impairment			(155.0	)		(181.0	)
	Carrying value after impairment		$	190.5		$	166.8
	The changes in the carrying value of goodwill by reportable segment for the fiscal years ended September 30, 2014 and 2013 were as follows:
			Fiscal Year 2014
			September 30,			Post-			Foreign			Acquired		September 30,
			2013			Acquisition			Exchange					2014
						Adjustments			Impact
			(in millions)
	Professional Technical Services		$	1,645.00		$	5		$	(31.3	)	$	151.8	$	1,770.50
	Management Support Services			166.8			—			—			—		166.8
	Total		$	1,811.80		$	5		$	(31.3	)	$	151.8	$	1,937.30
		Fiscal Year 2013
		September 30,			Post-			Foreign			Acquired		September 30,
		2012			Acquisition			Exchange					2013
					Adjustments			Impact
		(in millions)
Professional Technical Services		$	1,608.60		$	—		$	(36.2	)	$	72.6	$	1,645.00
Management Support Services			166.8			—			—			—		166.8
Total		$	1,775.40		$	—		$	(36.2	)	$	72.6	$	1,811.80
Included in the acquired goodwill above for the year ended September 30, 2014 is $79.1 million of recorded goodwill as a result of the consolidation of an unconsolidated joint venture, as further discussed in Note 7.
The gross amounts and accumulated amortization of the Company's acquired identifiable intangible assets with finite useful lives as of September 30, 2014 and 2013, included in intangible assets—net, in the accompanying consolidated balance sheets, were as follows:
		September 30, 2014									September 30, 2013
		Gross			Accumulated			Intangible			Gross		Accumulated			Intangible		Amortization
		Amount			Amortization			Assets, Net			Amount		Amortization			Assets, Net		Period
																		(years)
		(in millions)
Backlog		$	110		$	(97.4	)		12.6		$	94.9	$	(89.4	)	$	5.5	1 - 5
Customer relationships			161.6			(85.4	)		76.2			147.1		(69.5	)		77.6	10
Trademark / tradename			9.3			(7.9	)		1.4			7.8		(7.8	)		—	2
Total		$	280.9		$	(190.7	)	$	90.2		$	249.8	$	(166.7	)	$	83.1
Amortization expense of acquired intangible assets included within cost of revenue was $24.0 million and $21.2 million for the years ended September 30, 2014 and 2013, respectively. The following table presents estimated amortization expense of existing intangible assets for the succeeding years:
Fiscal Year		(in millions)
2015		$	26.5
2016			17.5
2017			13.2
2018			9.9
2019			9.0
Thereafter			14.1
Total		$	90.2

Accounts_ReceivableNet

Accounts Receivable-Net	12 Months Ended
	Sep. 30, 2014
Accounts Receivable-Net	'
Accounts Receivable-Net	'
	5. Accounts Receivable—Net
	Net accounts receivable consisted of the following:
		Fiscal Year Ended
		September 30,			September 30,
		2014			2013
		(in millions)
	Billed	$	1,248.40		$	1,177.60
	Unbilled		1,214.80			1,076.80
	Contract retentions		263.9			174.3
	Total accounts receivable—gross		2,727.10			2,428.70
	Allowance for doubtful accounts		(72.1	)		(86.4	)
	Total accounts receivable—net	$	2,655.00		$	2,342.30
	Billed accounts receivable represent amounts billed to clients that have yet to be collected. Unbilled accounts receivable represents the contract revenue recognized but not yet billed pursuant to contract terms or accounts billed after the period end. Substantially all unbilled receivables as of September 30, 2014 and 2013 are expected to be billed and collected within twelve months. Contract retentions represent amounts invoiced to clients where payments have been withheld pending the completion of certain milestones, other contractual conditions or upon the completion of the project. These retention agreements vary from project to project and could be outstanding for several months or years.
	Allowances for doubtful accounts have been determined through specific identification of amounts considered to be uncollectible and potential write-offs, plus a non-specific allowance for other amounts for which some potential loss has been determined to be probable based on current and past experience.
	Other than the U.S. government, no single client accounted for more than 10% of the Company's outstanding receivables at September 30, 2014 and 2013.
	The Company sold trade receivables to financial institutions, of which $111.9 million and $100.2 million were outstanding as of September 30, 2014 and 2013, respectively. The Company does not retain financial or legal obligations for these receivables that would result in material losses. The Company's ongoing involvement is limited to the remittance of customer payments to the financial institutions with respect to the sold trade receivables.

Property_and_Equipment

Property and Equipment	12 Months Ended
	Sep. 30, 2014
Property and Equipment.	'
Property and Equipment	'
	6. Property and Equipment
	Property and equipment, at cost, consists of the following:
		Fiscal Year Ended
		September 30,			September 30,			Useful Lives
		2014			2013			(years)
		(in millions)
	Building and land	$	11.5		$	4.4		27
	Leasehold improvements		299.7			289.9		2 - 12
	Computer systems and equipment		302.6			257		3 - 10
	Furniture and fixtures		101.5			106.4		5 - 10
	Automobiles		6.8			5.4		3 - 10
	Total		722.1			663.1
	Accumulated depreciation and amortization		(440.1	)		(392.4	)
	Property and equipment, net	$	282		$	270.7
	Depreciation expense for the fiscal years ended September 30, 2014, 2013 and 2012 were $69.1 million, $70.7 million and $77.1 million, respectively. Included in depreciation expense is amortization of capitalized software costs in the years ended September 30, 2014, 2013 and 2012 of $7.3 million, $6.4 million and $6.2 million, respectively. Unamortized capitalized software costs at September 30, 2014, 2013 and 2012 were $39.9 million, $29.6 million and $24.1 million, respectively.
	Depreciation is calculated using primarily the straight-line method over the estimated useful lives of the assets, or in the case of leasehold improvements and capitalized leases, the lesser of the remaining term of the lease or its estimated useful life.

Joint_Ventures_and_Variable_In

Joint Ventures and Variable Interest Entities	12 Months Ended
	Sep. 30, 2014
Joint Ventures and Variable Interest Entities	'
Joint Ventures and Variable Interest Entities	'
	7. Joint Ventures and Variable Interest Entities
	The Company's joint ventures provide architecture, engineering, program management, construction management and operations and maintenance services. Joint ventures, the combination of two or more partners, are generally formed for a specific project. Management of the joint venture is typically controlled by a joint venture executive committee, comprised of representatives from the joint venture partners. The joint venture executive committee normally provides management oversight and controls decisions which could have a significant impact on the joint venture.
	Some of the Company's joint ventures have no employees and minimal operating expenses. For these joint ventures, the Company's employees perform work for the joint venture, which is then billed to a third-party customer by the joint venture. These joint ventures function as pass through entities to bill the third-party customer. For consolidated joint ventures of this type, the Company records the entire amount of the services performed and the costs associated with these services, including the services provided by the other joint venture partners, in the Company's result of operations. For certain of these joint ventures where a fee is added by an unconsolidated joint venture to client billings, the Company's portion of that fee is recorded in equity in earnings of joint ventures.
	The Company also has joint ventures that have their own employees and operating expenses, and to which the Company generally makes a capital contribution. The Company accounts for these joint ventures either as consolidated entities or equity method investments based on the criteria further discussed below.
	The Company follows guidance issued by the FASB on the consolidation of variable interest entities (VIEs) that requires companies to utilize a qualitative approach to determine whether it is the primary beneficiary of a VIE. The process for identifying the primary beneficiary of a VIE requires consideration of the factors that indicate a party has the power to direct the activities that most significantly impact the joint ventures' economic performance, including powers granted to the joint venture's program manager, powers contained in the joint venture governing board and, to a certain extent, a company's economic interest in the joint venture. The Company analyzes its joint ventures and classifies them as either:
	•	a VIE that must be consolidated because the Company is the primary beneficiary or the joint venture is not a VIE and the Company holds the majority voting interest with no significant participative rights available to the other partners; or
	•	a VIE that does not require consolidation and is treated as an equity method investment because the Company is not the primary beneficiary or the joint venture is not a VIE and the Company does not hold the majority voting interest.
	As part of the above analysis, if it is determined that the Company has the power to direct the activities that most significantly impact the joint venture's economic performance, the Company considers whether or not it has the obligation to absorb losses or rights to receive benefits of the VIE that could potentially be significant to the VIE.
	Contractually required support provided to the Company's joint ventures is discussed in Note 20.
	Summary of unaudited financial information of the consolidated joint ventures is as follows:
			September 30,		September 30,
			2014		2013
			(in millions)
	Current assets		$	314.1	$	185.7
	Non-current assets			106.2		—
	Total assets		$	420.3	$	185.7
	Current liabilities		$	229.1	$	38.9
	Non-current liabilities			—		—
	Total liabilities			229.1		38.9
	Total AECOM equity			116.6		106.8
	Noncontrolling interests			74.6		40.0
	Total owners' equity			191.2		146.8
	Total liabilities and owners' equity		$	420.3	$	185.7
	Total revenue of the consolidated joint ventures was $614.5 million, $490.9 million and $468.6 million for the years ended September 30, 2014, 2013 and 2012, respectively. The assets of the Company's consolidated joint ventures are restricted for use only by the particular joint venture and are not available for the general operations of the Company.
	Summary of unaudited financial information of the unconsolidated joint ventures is as follows:
			September 30,		September 30,
			2014		2013
			(in millions)
	Current assets		$	539.6	$	525.5
	Non-current assets			273.7		98.7
	Total assets		$	813.3	$	624.2
	Current liabilities		$	397.9	$	384.1
	Non-current liabilities			91.0		17.5
	Total liabilities			488.9		401.6
	Joint venturers' equity			324.4		222.6
	Total liabilities and joint venturers' equity		$	813.3	$	624.2
	AECOM's investment in joint ventures		$	142.9	$	106.4
	Total revenue of the unconsolidated joint ventures was $2.0 billion, $2.1 billion and $2.0 billion for the years ended September 30, 2014, 2013 and 2012, respectively. Total operating income of the unconsolidated joint ventures were $57.7 million, $70.1 million and $127.5 million for the years ended September 30, 2014, 2013 and 2012, respectively.
	Summary of AECOM's equity in earnings of unconsolidated joint ventures is as follows:
			Fiscal Year Ended
			September 30,		September 30,		September 30,
			2014		2013		2012
			(in millions)
	Pass through joint ventures		$	10.2	$	6.4	$	5.2
	Other joint ventures			47.7		17.9		43.4
	Total		$	57.9	$	24.3	$	48.6
	Included in equity in earnings above is a $37.4 million gain recognized upon change in control ($23.4 million, net of tax) of an unconsolidated joint venture in the year ended September 30, 2014. The Company obtained control of the joint venture through modifications to the joint venture's operating agreement, which required the Company to consolidate the joint venture. The acquisition date fair value of the previously held equity interest was $58.0 million, excluding the control premium. The measurement of the fair value of the equity interest immediately before obtaining control of the joint venture resulted in the pre-tax gain of $37.4 million. The Company utilized income and market approaches, in addition to obtaining an independent third party valuation, in determining the joint venture's fair value, which includes making assumptions about variables such as revenue growth rates, profitability, discount rates, and industry market multiples. These assumptions are subject to a high degree of judgment. Total assets and liabilities of this entity included in the accompanying consolidated balance sheet at the acquisition date were $207.8 million and $48.1 million, respectively. This acquisition did not meet the quantitative thresholds to require pro forma disclosures of operating results based on the Company's consolidated assets, investments and net income. This joint venture performs engineering and program management services in the Middle East and is included in the Company's PTS segment.

Pension_Plans

Pension Plans	12 Months Ended
	Sep. 30, 2014
Pension Plans	'
Pension Plans	'
	8. Pension Plans
	In the U.S., the Company sponsors a Defined Benefit Pension Plan (the Pension Plan) which covers substantially all permanent employees hired as of March 1, 1998, subject to eligibility and vesting requirements, and required contributions from participating employees through March 31, 1998. Benefits under this plan generally are based on the employee's years of creditable service and compensation. Effective April 1, 2004, the Company set a maximum on the amount of compensation used to determine pension benefits based on the highest calendar year of compensation earned in the 10 completed calendar years from 1994 through 2003, or the relevant IRS annual compensation limit, whichever is lower. Outside the U.S., the Company sponsors various pension plans, which are appropriate to the country in which the Company operates, some of which are government mandated.
	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,						September 30,						September 30,
		2014						2013						2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Change in benefit obligation:
	Benefit obligation at beginning of year	$	180.3		$	622.1		$	192.9		$	574		$	171		$	504.3
	Service cost		—			0.7			—			0.9			—			1.1
	Participant contributions		0.4			0.2			0.4			0.3			0.6			0.3
	Interest cost		7.8			27.9			6.6			23.8			7.7			25.6
	Benefits paid		(12.8	)		(23.3	)		(11.0	)		(18.8	)		(10.0	)		(25.7	)
	Actuarial (gain) loss		23.2			62.3			(8.6	)		49			23.6			50.3
	Plan settlements		—			(2.0	)		—			(5.7	)		—			(2.4	)
	Net transfer in/(out)/acquisitions		18.1			—			—			—			—			—
	Foreign currency translation (gain) loss		—			(11.3	)		—			(1.4	)		—			20.5
	Benefit obligation at end of year	$	217		$	676.6		$	180.3		$	622.1		$	192.9		$	574
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		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	$	119.8		$	489.9		$	112.3		$	462.4		$	91.5		$	417.3
	Actual return on plan assets		14.2			60.4			11.3			37.4			17			39
	Employer contributions		4.9			16.4			6.8			16.2			13.2			17.2
	Participant contributions		0.4			0.2			0.4			0.3			0.6			0.3
	Benefits paid		(12.8	)		(23.3	)		(11.0	)		(18.8	)		(10.0	)		(25.7	)
	Plan settlements		—			(2.0	)		—			(5.7	)		—			(2.4	)
	Net transfer in/(out)/acquisitions		13.2			—			—			—			—			—
	Foreign currency translation (loss) gain		—			(9.0	)		—			(1.9	)		—			16.7
	Fair value of plan assets at end of year	$	139.7		$	532.6		$	119.8		$	489.9		$	112.3		$	462.4
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Reconciliation of funded status:
	Funded status at end of year	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
	Contribution made after measurement date		N/A			N/A			N/A			N/A			N/A			N/A
	Net amount recognized at end of year	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
	The following table sets forth the amounts recognized in the consolidated balance sheets as of September 30, 2014, 2013 and 2012:
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		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	$	—		$	1.1		$	—		$	0.6		$	—		$	—
	Accrued expenses and other current liabilities		(1.7	)		—			(1.4	)		—			(1.7	)		—
	Other long-term liabilities		(75.6	)		(145.1	)		(59.1	)		(132.8	)		(78.9	)		(111.6	)
	Net amount recognized in the balance sheet	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
	The following table details the reconciliation of amounts in the consolidated statements of stockholders' equity for the fiscal years ended September 30, 2014, 2013 and 2012:
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		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 credit	$	—		$	5.8		$	—		$	6		$	—		$	6.2
	Net (loss)		(113.0	)		(190.1	)		(99.4	)		(170.7	)		(115.1	)		(143.2	)
	Total recognized in accumulated other comprehensive (loss)	$	(113.0	)	$	(184.3	)	$	(99.4	)	$	(164.7	)	$	(115.1	)	$	(137.0	)
	The following table details the components of net periodic benefit cost for the plans in fiscal 2014, 2013 and 2012:
		Fiscal Year Ended
	September 30,						September 30,						September 30,
	2014						2013						2012
	U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
	(in millions)
Components of net periodic (benefit) cost:
Service costs	$	—		$	0.7		$	—		$	1		$	—		$	1.1
Interest cost on projected benefit obligation		7.8			27.9			6.6			23.8			7.7			25.6
Expected return on plan assets		(8.6	)		(26.1	)		(8.5	)		(22.7	)		(8.4	)		(25.3	)
Amortization of prior service costs		—			(0.2	)		—			(0.2	)		—			(0.2	)
Amortization of net loss		4			4.9			4.3			4			3.1			2.3
Settlement loss recognized		—			0.4			—			2.6			—			0.5
Net periodic (benefit) cost	$	3.2		$	7.6		$	2.4		$	8.5		$	2.4		$	4
The amount, net of applicable deferred income taxes, included in other comprehensive income arising from a change in net prior service cost and net gain/loss was $7.6 million, $2.6 million and $9.0 million in the years ended September 30, 2014, 2013 and 2012, respectively.
Amounts included in accumulated other comprehensive loss as of September 30, 2014 that are expected to be recognized as components of net periodic benefit cost during fiscal 2015 are (in millions):
	U.S.			Int'l
Amortization of prior service cost	$	—		$	0.2
Amortization of net actuarial losses		(4.3	)		(6.2	)
Total	$	(4.3	)	$	(6.0	)
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,						September 30,						September 30,
	2014						2013						2012
	U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
	(in millions)
Projected benefit obligation	$	217.0		$	658.5		$	180.3		$	601.7		$	192.9		$	574.0
Accumulated benefit obligation		217.0			656.3			180.3			599.8			192.9			570.6
Fair value of plan assets		139.7			513.4			119.8			469.0			112.3			462.4
Funding requirements for each plan are determined based on the local laws of the country where such plan resides. In certain countries, the funding requirements are mandatory while in other countries, they are discretionary. The Company currently intends to contribute $17.0 million to the international plans in fiscal 2015. The Company does not have a required minimum contribution for the U.S. plans; however, the Company may make discretionary contributions. The Company currently intends to contribute $5.4 million to U.S. plans in fiscal 2015.
The table below provides the expected future benefit payments, in millions:
Year Ending September 30,	U.S.			Int'l
2015	$	12.2		$	26.5
2016		14.9			21.9
2017		13.4			26.3
2018		12.9			29.1
2019		13.4			25.8
2020 - 2024		68.3			153.3
Total	$	135.1		$	282.9
The underlying assumptions for the pension plans are as follows:
	Fiscal Year Ended
	September 30,						September 30,						September 30,
	2014						2013						2012
	U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
Weighted-average assumptions to determine benefit obligation:
Discount rate		4.00	%		3.94	%		4.40	%		4.44	%		3.50	%		4.39	%
Salary increase rate		N/A			2.38	%		N/A			2.58	%		N/A			2.36	%
Weighted-average assumptions to determine net periodic benefit cost:
Discount rate		4.40	%		4.44	%		3.50	%		4.39	%		4.65	%		5.12	%
Salary increase rate		N/A			2.58	%		N/A			2.36	%		N/A			2.65	%
Expected long-term rate of return on plan assets		7.50	%		5.40	%		7.50	%		5.11	%		7.50	%		5.65	%
Pension costs are determined using the assumptions as of the beginning of the plan year, October 1. The funded status is determined using the assumptions as of the end of the plan year.
The following table summarizes the Company's target allocation for 2014 and pension plan asset allocation, both U.S. and international, as of September 30, 2014 and 2013:
							Percentage of Plan Assets
	Target						as of September 30,
	Allocations						2014						2013
	U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
Asset Category
Equities		45	%		1	%		58	%		28	%		49	%		28	%
Debt		42			47			31			33			34			37
Cash		3			1			1			3			1			4
Property and other		10			51			10			36			16			31
Total		100	%		100	%		100	%		100	%		100	%		100	%
The Company's policy is to minimize the risk of large losses through diversification in a portfolio of stocks, bonds, and cash equivalents, as appropriate, which may reflect varying rates of return. The percentage of assets allocated to cash is to assure liquidity to meet benefit disbursements and general operating expenses.
To develop the expected long-term rate of return on assets assumption, the Company considered the historical returns and the future expectations for returns for each asset class, as well as the target asset allocation of the pension portfolio and the diversification of the portfolio. This resulted in the selection of a 7.5% and 5.4% weighted-average long-term rate of return on assets assumption for the fiscal year ended September 30, 2014 for U.S. and non-U.S. plans, respectively.
As of September 30, 2014, the fair values of the Company's post- retirement benefit plan assets by major asset categories were as follows:
				Fair Value Measurement as of
				September 30, 2014
	Total			Quoted			Significant			Significant
	Carrying			Prices in			Other			Unobservable
	Value as of			Active			Observable			Inputs
	September 30,			Markets			Inputs			(Level 3)
	2014			(Level 1)			(Level 2)
	(in millions)
Cash and cash equivalents	$	7.9		$	3.4		$	4.5		$	—
Investment funds
Diversified funds		159.3			—			159.3			—
Equity funds		220.3			—			220.3			—
Fixed income funds		219.3			—			219.3			—
Hedge funds		27.9			—			14.2			13.7
Assets held by insurance company		37.6			—			37.6			—
Total	$	672.3		$	3.4		$	655.2		$	13.7
As of September 30, 2013, the fair values of the Company's post- retirement benefit plan assets by major asset categories are as follows:
				Fair Value Measurement as of September 30, 2013
	Total			Quoted			Significant			Significant
	Carrying			Prices in			Other			Unobservable
	Value as of			Active			Observable			Inputs
	September 30,			Markets			Inputs			(Level 3)
	2013			(Level 1)			(Level 2)
	(in millions)
Cash and cash equivalents	$	11.0		$	11.0		$	—		$	—
Investment funds
Diversified funds		108.6			—			108.6			—
Equity funds		192.4			—			192.4			—
Fixed income funds		220.6			—			220.6			—
Hedge funds		25.0			—			12.4			12.6
Assets held by insurance company		46.1			—			46.1			—
Real estate		6.0			—			6.0			—
Total	$	609.7		$	11.0		$	586.1		$	12.6
Changes for the year ended September 30, 2014, in the fair value of the Company's recurring post-retirement plan Level 3 assets are as follows:
	September 30,			Actual return			Actual return			Purchases,			Transfer			Change			September 30,
	2013			on plan assets,			on plan assets,			sales and			into /			due to			2014
	Beginning			relating to			relating to			settlements			(out of)			exchange			Ending
	balance			assets still held			assets sold						Level 3			rate			balance
				at reporting			during the									changes
				date			period
	(in millions)
Investment funds
Hedge funds	$	12.6		$	1.1		$	—		$	—		$	—		$	—		$	13.7
Total	$	12.6		$	1.1		$	—		$	—		$	—		$	—		$	13.7
Changes for the year ended September 30, 2013, in the fair value of the Company's recurring post-retirement plan Level 3 assets are as follows:
	September 30,			Actual return			Actual return			Purchases,			Transfer			Change			September 30,
	2012			on plan assets,			on plan assets,			sales			into /			due to			2013
	Beginning			relating to			relating to			and			(out of)			exchange			Ending
	balance			assets still held			assets sold			settlements			Level 3			rate			balance
				at reporting			during the									changes
				date			period
	(in millions)
Investment funds
Hedge funds	$	10.6		$	2.0		$	—		$	—		$	—		$	—		$	12.6
Total	$	10.6		$	2.0		$	—		$	—		$	—		$	—		$	12.6
Cash equivalents are mostly comprised of short-term money-market instruments and are valued at cost, which approximates fair value.
For equity investment funds not traded on an active exchange, or if the closing price is not available, the trustee obtains indicative quotes from a pricing vendor, broker, or investment manager. These funds are categorized as Level 2 if the custodian obtains corroborated quotes from a pricing vendor or categorized as Level 3 if the custodian obtains uncorroborated quotes from a broker or investment manager.
Fixed income investment funds categorized as Level 2 are valued by the trustee using pricing models that use verifiable observable market data (e.g., interest rates and yield curves observable at commonly quoted intervals), bids provided by brokers or dealers, or quoted prices of securities with similar characteristics.
Hedge funds categorized as Level 3 are valued based on valuation models that include significant unobservable inputs and cannot be corroborated using verifiable observable market data. Hedge funds are valued by independent administrators. Depending on the nature of the assets, the general partners or independent administrators use both the income and market approaches in their models. The market approach consists of analyzing market transactions for comparable assets while the income approach uses earnings or the net present value of estimated future cash flows adjusted for liquidity and other risk factors. As of September 30, 2014, there were no material changes to the valuation techniques.

Debt

Debt	12 Months Ended
	Sep. 30, 2014
Debt	'
Debt	'
	9. Debt
	Debt consisted of the following:
		September 30,			September 30,
		2014			2013
		(in millions)
	Unsecured term credit agreement	$	712.5		$	750
	Unsecured senior notes		263.9			260.2
	Unsecured revolving credit facility		—			114.7
	Other debt		27.6			48.4
	Total debt		1,004.00			1,173.30
	Less: Current portion of debt and short-term borrowings		(64.4	)		(84.3	)
	Long-term debt, less current portion	$	939.6		$	1,089.00
	The following table presents, in millions, scheduled maturities of our debt as of September 30, 2014:
	Fiscal Year
	2015	$	64.4
	2016		38.0
	2017		37.7
	2018		600.0
	2019		—
	Thereafter		263.9
	Total	$	1,004.0
	Unsecured Term Credit Agreement
	In June 2013, the Company entered into a Second Amended and Restated Credit Agreement (Term Credit Agreement) with Bank of America, N.A., as administrative agent and a lender, and the other lenders party thereto. Pursuant to the Term Credit Agreement, the Company borrowed $750 million and may borrow up to an additional $100 million subject to certain conditions, including Company and lender approval. The Company used approximately $675 million of the proceeds from the loans to repay indebtedness under our prior term loan facility. The loans under the Term Credit Agreement bear interest, at our option, at either the Base Rate (as defined in the Term Credit Agreement) plus an applicable margin or the Eurodollar Rate (as defined in the Term Credit Agreement) plus an applicable margin. The applicable margin for the Base Rate loans is a range of 0.125% to 1.250% and the applicable margin for Eurodollar Rate loans is a range of 1.125% to 2.250%, both based on our debt-to-earnings leverage ratio at the end of each fiscal quarter. For the years ended September 30, 2014 and 2013, the average interest rate of the Company's term loan facility was 1.66% and 1.98%, respectively. Payments of the initial principal amount outstanding under the Term Credit Agreement are required on an annual basis and began on June 30, 2014 with the final principal balance of $600 million due on June 7, 2018. The Company may, at its option, prepay the loans at any time, without penalty. The Company's obligations under the Term Credit Agreement are guaranteed by certain of our subsidiaries pursuant to one or more subsidiary guarantees.
	Unsecured Senior Notes
	In July 2010, the Company issued $300 million of notes to private institutional investors. The notes consisted of $175.0 million of 5.43% Senior Notes, Series A, due July 2020 and $125.0 million of 1.00% Senior Discount Notes, Series B, due July 2022 for net proceeds of $249.8 million. The outstanding accreted balance of Series B Notes, which have an effective interest rate of 5.62%, was $88.9 million and $85.2 million at September 30, 2014 and 2013, respectively. The fair value of the Company's unsecured senior notes was approximately $287.4 million and $269.4 million at September 30, 2014 and 2013, respectively. The Company calculated the fair values based on model-derived valuations using market observable inputs, which are Level 2 inputs under the accounting guidance. The Company's obligations under the notes are guaranteed by certain of its subsidiaries pursuant to one or more subsidiary guarantees. The Company has the option to prepay the notes at any time at their called principal amount, together with any accrued and unpaid interest, plus a make-whole premium.
	Unsecured Revolving Credit Facility
	In January 2014, the Company entered into a Fourth Amended and Restated Credit Agreement (Revolving Credit Agreement), which provides for a borrowing capacity of $1.05 billion. The Revolving Credit Agreement expires on January 29, 2019, and prior to this expiration date, principal amounts outstanding under the Revolving Credit Agreement may be repaid and reborrowed at the Company's option without prepayment or penalty, subject to certain conditions including the absence of any event of default. The Company may request an increase in capacity of up to a total of $1.25 billion, subject to certain conditions including the absence of any event of default. The loans under the Revolving Credit Agreement may be borrowed in dollars or in certain foreign currencies and bear interest, at our option, at either the Base Rate (as defined in the Revolving Credit Agreement) plus an applicable margin or the Eurocurrency Rate (as defined in the Revolving Credit Agreement) plus an applicable margin. The applicable margin for the Base Rate loans is a range of 0.125% to 1.250% and the applicable margin for the Eurocurrency Rate loans is a range of 1.125% to 2.250%, both based on the Company's debt-to-earnings leverage ratio at the end of each fiscal quarter. In addition to these borrowing rates, there is a commitment fee which ranges from 0.125% to 0.350% on any unused commitment. At September 30, 2014 and 2013, $0.0 million and $114.7 million, respectively, were outstanding under the Company's revolving credit facility. At September 30, 2014 and 2013, outstanding standby letters of credit totaled $12.1 million and $35.5 million, respectively, under the Company's revolving credit facility. As of September 30, 2014, the Company had $1,037.9 million available under our Revolving Credit Agreement.
	Covenants and Restrictions
	Under the Company's debt agreements relating to its unsecured revolving credit facility, unsecured term credit agreement, and unsecured senior notes, the Company is subject to a maximum consolidated leverage ratio at the end of each fiscal quarter. This ratio is calculated by dividing consolidated funded debt (including financial letters of credit and other adjustments per its debt agreements) by consolidated earnings before interest, taxes, depreciation, and amortization (EBITDA). Subject to certain differences among our debt agreements, EBITDA is defined as consolidated net income attributable to AECOM plus interest, depreciation and amortization expense, amounts set aside for taxes and other non-cash items (including a calculated annualized EBITDA from our acquisitions). As of September 30, 2014, the Company's most restrictive consolidated leverage ratio under its debt agreements was 2.55, which did not exceed the Company's maximum consolidated leverage ratio permitted under its debt agreements of 3.0.
	Our Revolving Credit Agreement and Term Credit Agreement also contain certain covenants that limit our ability to, among other things, (i) merge with other entities, (ii) enter into a transaction resulting in a change of control, (iii) create new liens, (iv) sell assets outside of the ordinary course of business, (v) enter into transactions with affiliates, (vi) substantially change the general nature of the Company and its subsidiaries taken as a whole, and (vii) incur indebtedness and contingent obligations.
	Additionally, the Company's unsecured senior notes contain covenants that limit (i) certain types of indebtedness, which include indebtedness incurred by subsidiaries and indebtedness secured by a lien, (ii) merging with other entities, (iii) entering into a transaction resulting in a change of control, (iv) creating new liens, (v) selling assets outside of the ordinary course of business, (vi) entering into transactions with affiliates, and (vii) substantially changing the general nature of our Company and our subsidiaries taken as a whole. The unsecured senior notes also contain a financial covenant that requires us to maintain a net worth above a calculated threshold. The threshold is calculated as $1.2 billion plus 40% of the consolidated net income for each fiscal quarter commencing with the fiscal quarter ending June 30, 2010. In the calculation of this threshold, the Company cannot include a consolidated net loss that may occur in any fiscal quarter. The Company's net worth for this financial covenant is defined as total AECOM stockholders' equity, which is consolidated stockholders' equity, including any redeemable common stock and stock units and the liquidation preference of any preferred stock. As of September 30, 2014, this amount was $2.2 billion, which exceeds the calculated threshold of $1.7 billion.
	Should the Company fail to comply with these covenants, all or a portion of its borrowings under the unsecured senior notes and unsecured term credit agreements could become immediately payable and its unsecured revolving credit facility could be terminated. At September 30, 2014 and 2013, the Company was in compliance with all such covenants.
	The Company's average effective interest rate on total borrowings, including the effects of the interest rate swap agreements, during the year ended September 30, 2014, 2013 and 2012 was 2.8%, 3.0% and 3.1%, respectively.
	Other Debt
	Other debt consists primarily of bank overdrafts, obligations under capital leases, and other unsecured credit facilities. In addition to the unsecured revolving credit facility discussed above, the Company also has other unsecured credit facilities primarily used for standby letters of credit issued for payment of performance guarantees. At September 30, 2014 and 2013, these outstanding standby letters of credit totaled $301.0 million and $236.4 million, respectively. As of September 30, 2014 and 2013, the Company had $327.4 million and $331.8 million, respectively, available under these unsecured credit facilities.

Derivative_Financial_Instrumen

Derivative Financial Instruments	12 Months Ended
	Sep. 30, 2014
Derivative Financial Instruments	'
Derivative Financial Instruments	'
	10. Derivative Financial Instruments
	The Company uses certain interest rate derivative contracts to hedge interest rate exposures on the Company's variable rate debt. The Company enters into foreign currency derivative contracts with financial institutions to reduce the risk that its cash flows and earnings will be adversely affected by foreign currency exchange rate fluctuations. The Company's hedging program is not designated for trading or speculative purposes.
	The Company recognizes derivative instruments as either assets or liabilities on the accompanying consolidated balance sheets at fair value. The Company records changes in the fair value (i.e., gains or losses) of the derivatives that have been designated as accounting hedges in the accompanying consolidated statements of operations as cost of revenue, interest expense or to accumulated other comprehensive loss in the accompanying consolidated balance sheets.
	Cash Flow Hedges
	The Company uses interest rate swap agreements designated as cash flow hedges to fix the variable interest rates on portions of the Company's debt. The Company also uses foreign currency options designated as cash flow hedges to hedge forecasted revenue transactions denominated in currencies other than the U.S. dollar. The Company initially reports any gain on the effective portion of a cash flow hedge as a component of accumulated other comprehensive loss. Depending on the type of cash flow hedge, the gain is subsequently reclassified to either interest expense when the interest expense on the variable rate debt is recognized, or to cost of revenue when the hedged revenues are recorded. If the hedged transaction becomes probable of not occurring, any gain or loss related to interest rate swap agreements or foreign currency options would be recognized in other income (expense). Further, the Company excludes the change in the time value of the foreign currency options from the assessment of hedge effectiveness. The Company records the premium paid or time value of an option on the date of purchase as an asset. Thereafter, the Company recognizes any change to this time value in cost of revenue.
	The notional principal, fixed rates and related expiration dates of the Company's outstanding interest rate swap agreements were as follows:
			September 30, 2014
			Notional Amount			Fixed			Expiration
			(in millions)			Rate			Date
			$	300.0			1.63	%	Jun-18
				250.0			0.95	%	Sep-15
				200.0			0.68	%	Dec-14
			September 30, 2013
			Notional Amount			Fixed			Expiration
			(in millions)			Rate			Date
			$	250.0			0.95	%	Sep-15
				200.0			0.68	%	Dec-14
				150.0			0.55	%	Dec-13
	There were no foreign currency options to purchase British Pounds (GBP) with Brazilian Reals (BRL) at September 30, 2014. The notional principal of foreign currency options to purchase GBP with BRL was BRL 2.1 million (or approximately $0.9 million) at September 30, 2013.
	Foreign Currency Forward Contracts
	The Company uses foreign currency forward contracts, which are not designated as accounting hedges, to hedge intercompany transactions and other monetary assets or liabilities denominated in currencies other than the functional currency of a subsidiary. Gains and losses on these contracts are recognized in cost of revenue for those instruments related to the provision of their respective services or general and administrative expenses, along with the offsetting losses and gains of the related hedged items. The notional principal of foreign currency forward contracts to purchase U.S. dollars with foreign currencies was $69.5 million at September 30, 2014. The notional principal of foreign currency forward contracts to sell U.S. dollars for foreign currencies was $71.5 million at September 30, 2014. The notional principal of foreign currency forward contracts to purchase GBP with BRL was BRL 1.1 million (or approximately $0.4 million) at September 30, 2014. The notional principal of foreign currency forward contracts to purchase U.S. dollars with foreign currencies was $171.8 million at September 30, 2013. The notional principal of foreign currency forward contracts to sell U.S. dollars for foreign currencies was $174.2 million at September 30, 2013. The notional principal of foreign currency forward contracts to purchase GBP with BRL was BRL 4.0 million (or approximately $1.8 million) at September 30, 2013. The notional principal of foreign currency forward contracts to sell GBP for BRL was BRL 8.2 million (or approximately $3.6 million) at September 30, 2013.
	Other Derivatives
	Other derivatives that are not designated as hedging instruments consist of option contracts that the Company uses to hedge anticipated transactions in currencies other than the functional currency of a subsidiary. The Company recognizes gains and losses on these contracts as well as the offsetting losses and gains of the related hedged item costs in cost of revenue. The Company records the premium paid or time value of an option on the date of purchase as an asset. Thereafter, the Company recognizes any change to this time value in cost of revenue. There were no such option contracts were outstanding at September 30, 2014 and 2013.
	The fair values of our outstanding derivative instruments were as follows (in millions):
					Fair Value of
					Derivative
					Instruments
					as of
			Balance Sheet Location		Sep 30,			Sep 30,
					2014			2013
	Derivative assets
	Derivatives designated as hedging instruments:
	Foreign currency options		Prepaid expenses and other current assets		$	—		$	0.1
	Interest rate swap agreements		Other non-current asset			1.7			—
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		Prepaid expenses and other current assets			3.1			1.6
	Total				$	4.8		$	1.7
	Derivative liabilities
	Derivatives designated as hedging instruments:
	Interest rate swap agreements		Accrued expenses and other current liabilities		$	4.8		$	2.6
	Interest rate swap agreements		Other long-term liabilities			—			1.1
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		Accrued expenses and other current liabilities			3.7			1.5
	Total				$	8.5		$	5.2
	At September 30, 2014, the effective portion of the Company's interest rate swap agreements designated as cash flow hedges before tax effect was $3.0 million, of which $4.8 million is expected to be reclassified from accumulated other comprehensive loss to interest expense within the next 12 months. At September 30, 2014, the effective portion of the Company's foreign currency options designated as cash flow hedges before tax effect were immaterial.
	The effect of derivative instruments in cash flow hedging relationships on income and other comprehensive income is summarized below (in millions):
			Increase in Losses
			Recognized in Accumulated
			Other Comprehensive Loss
			on Derivatives Before Tax
			Effect (Effective Portion)
			Year Ended September 30,
			2014			2013			2012
	Derivatives in cash flow hedging relationship:
	Interest rate swap agreements		$	(2.4	)	$	(0.5	)	$	(8.4	)
					Losses Reclassified from
					Accumulated Other
					Comprehensive Loss into
					Income (Effective Portion)
					Year Ended September 30,
			Location		2014			2013			2012
	Derivatives in cash flow hedging relationship:
	Interest rate swap agreements		Interest expense		$	(2.9	)	$	(3.1	)	$	(2.2	)
Foreign currency options		Cost of revenue			(0.1	)		—			—
				Losses Recognized in
				Income on Derivatives
				(Amount Excluded from
				Effectiveness Testing and
				Ineffective Portion)(1)
				Year Ended September 30,
		Location		2014			2013			2012
Derivatives in cash flow hedging relationship:
Foreign currency options		Cost of revenue		$	—		$	(0.1	)	$	(0.1	)
-1	Losses related to the ineffective portion of the hedges were not material in all periods presented.
The gain recognized in accumulated other comprehensive loss from the Company's foreign currency options was immaterial for all years presented. The gain reclassified from accumulated other comprehensive loss into income from the foreign currency options was immaterial for all years presented. Additionally, there were no losses recognized in income due to amounts excluded from effectiveness testing from the Company's interest rate swap agreements.
The effect of derivative instruments not designated as hedging instruments on income is summarized below (in millions):
				Gains / (Losses) Recognized
				in Income on Derivatives
				(Amount Excluded from
				Effectiveness Testing and
				Ineffective Portion)(1)
				Year Ended September 30,
		Location		2014			2013			2012
Derivatives not designated as hedging instruments:
Foreign currency forward contracts		General and administrative expenses		$	(0.1	)	$	(4.7	)	$	4.2
Foreign currency forward contracts		Cost of revenue			—			—			0.1
Option contracts		Cost of revenue			—			(0.3	)		(0.1	)
				$	(0.1	)	$	(5.0	)	$	4.2
-1	Losses related to the ineffective portion of the hedges were not material in all periods presented.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Fair Value Measurements	'
	11. Fair Value Measurements
	Fair value is the price that would be received from selling an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. When determining fair value, the Company considers the principal or most advantageous market in which it would transact, and the Company considers assumptions that market participants would use when pricing the asset or liability. It measures certain financial and nonfinancial assets and liabilities at fair value on a recurring and nonrecurring basis.
	Nonfinancial assets and liabilities include items such as goodwill and long lived assets that are measured at fair value resulting from impairment, if deemed necessary. During the year ended September 30, 2012, the Company recognized an impairment of goodwill within both its PTS and MSS reportable segments. For further information regarding the impairment of goodwill refer to Note 4 herein.
	Fair Value Hierarchy
	The three levels of inputs may be used to measure fair value, as discussed in Note 1. There were no significant transfers between any of the levels of the fair value hierarchy during the years ended September 30, 2014 and 2013. The Company classifies its derivative financial instruments within Level 2 as the valuation inputs are based on quoted prices and market observable data of similar instruments.
	The following table summarizes the Company's non-pension financial assets and liabilities measured at fair value on a recurring basis (at least annually) in millions:
		September 30,		Quoted Prices in
		2014		Active Markets for
				Similar Assets
				(Level 2)
	Interest rate swap agreements	$	1.7	$	1.7
	Foreign currency forward contracts		3.1		3.1
	Total assets	$	4.8	$	4.8
	Interest rate swap agreements	$	4.8	$	4.8
	Foreign currency forward contracts		3.7		3.7
	Total liabilities	$	8.5	$	8.5
		September 30,		Quoted Prices in
		2013		Active Markets for
				Similar Assets
				(Level 2)
	Foreign currency options	$	0.1	$	0.1
	Foreign currency forward contracts		1.6		1.6
	Total assets	$	1.7	$	1.7
	Interest rate swap agreements	$	3.7	$	3.7
	Foreign currency forward contracts		1.5		1.5
	Total liabilities	$	5.2	$	5.2
	For additional information about the Company's derivative financial instruments refer to Note 10 herein.

Concentration_of_Credit_Risk

Concentration of Credit Risk	12 Months Ended
	Sep. 30, 2014
Concentration of Credit Risk	'
Concentration of Credit Risk	'
	12. Concentration of Credit Risk
	Financial instruments which potentially subject the Company to concentrations of credit risk consist principally of cash investments and trade receivables. The Company's cash balances and short-term investments are maintained in accounts held by major banks and financial institutions located primarily in the U.S., Canada, Europe, Australia, Middle East and Hong Kong. If the Company extends significant credit to clients in a specific geographic area or industry, the Company may experience disproportionately high levels of default if those clients are adversely affected by factors particular to their geographic area or industry. Concentrations of credit risk with respect to trade receivables are limited due to the large number of customers comprising the Company's customer base, including, in large part, governments, government agencies and quasi-government organizations, and their dispersion across many different industries and geographies. See Note 21 regarding the Company's foreign revenues. In order to mitigate credit risk, the Company continually reviews the credit worthiness of its major private clients.

Leases

Leases	12 Months Ended
	Sep. 30, 2014
Leases	'
Leases	'
	13. Leases
	The Company and its subsidiaries are lessees in non-cancelable leasing agreements for office buildings and equipment. The related payments are expensed on a straight-line basis over the lease term, including, as applicable, any free-rent period during which the Company has the right to use the asset. For leases with renewal options where the renewal is reasonably assured, the lease term, including the renewal period is used to determine the appropriate lease classification and to compute periodic rental expense. The following table presents, in millions, amounts payable under non-cancelable operating lease commitments during the following fiscal years:
	Year Ending September 30,
	2015	$	181.4
	2016		154.8
	2017		126.4
	2018		102.6
	2019		86.1
	Thereafter		234.7
	Total	$	886.0
	Rent expense for leases for the years ended September 30, 2014, 2013 and 2012 was approximately $210.4 million, $225.4 million and $237.4 million, respectively. When the Company is required to restore leased facilities to original condition, provisions are made over the period of the lease.

Other_Financial_Information

Other Financial Information	12 Months Ended
	Sep. 30, 2014
Other Financial Information	'
Other Financial Information	'
	14. Other Financial Information
	Accrued expenses and other current liabilities consist of the following:
		Fiscal Year Ended
		September 30,		September 30,
		2014		2013
		(in millions)
	Accrued salaries and benefits	$	400.6	$	410.6
	Accrued contract costs		446.4		404.2
	Other accrued expenses		117.6		100.5
		$	964.6	$	915.3
	Accrued contract costs above include balances related to professional liability accruals of $120.2 million and $121.3 million as of September 30, 2014 and 2013, respectively. The remaining accrued contract costs primarily relate to costs for services provided by subcontractors and other non-employees.
	Other long-term liabilities consist of the following:
		Fiscal Year Ended
		September 30,		September 30,
		2014		2013
		(in millions)
	Pension liabilities (Note 8)	$	221.3	$	192.7
	Reserve for uncertain tax positions (Note 18)		52.6		60.2
	Other		181.7		196.0
		$	455.6	$	448.9

Reclassification_out_of_Accumu

Reclassification out of Accumulated Other Comprehensive Loss	12 Months Ended
	Sep. 30, 2014
Reclassifications out of Accumulated Other Comprehensive Loss	'
Reclassifications out of Accumulated Other Comprehensive Loss	'
	15. Reclassifications out of Accumulated Other Comprehensive Loss
	The accumulated balances and reporting period activities for the years ended September 30, 2014, 2013 and 2012 related to reclassifications out of accumulated other comprehensive loss are summarized as follows (in millions):
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2011		$	(136.5	)	$	(51.1	)	$	—		$	(187.6	)
	Other comprehensive income before reclassification			(44.7	)		53.8			(5.0	)		4.1
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			3			—			—			3
	Cash flow hedge losses, net of tax			—			—			1.3			1.3
	Balances at September 30, 2012		$	(178.2	)	$	2.7		$	(3.7	)	$	(179.2	)
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2012		$	(178.2	)	$	2.7		$	(3.7	)	$	(179.2	)
	Other comprehensive income before reclassification			(19.9	)		(69.1	)		(0.2	)		(89.2	)
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			5.3			—			—			5.3
	Cash flow hedge losses, net of tax			—			—			1.8			1.8
	Balances at September 30, 2013		$	(192.8	)	$	(66.4	)	$	(2.1	)	$	(261.3	)
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2013		$	(192.8	)	$	(66.4	)	$	(2.1	)	$	(261.3	)
	Other comprehensive income before reclassification			(30.3	)		(71.4	)		(1.4	)		(103.1	)
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			6.1			—			—			6.1
	Cash flow hedge losses, net of tax			—			—			1.7			1.7
	Balances at September 30, 2014		$	(217.0	)	$	(137.8	)	$	(1.8	)	$	(356.6	)
			Year Ended			Year Ended			Year Ended
			September 30,			September 30,			September 30,
			2014			2013			2012
	Cash flow hedges(1)		$	2.9		$	3		$	2.2
	Taxes			(1.2	)		(1.2	)		(0.9	)
	Cash flow hedges, net of tax		$	1.7		$	1.8		$	1.3
	Actuarial losses(2)		$	8.7		$	8		$	4.7
	Taxes			(2.6	)		(2.7	)		(1.7	)
	Actuarial losses, net of tax		$	6.1		$	5.3		$	3
	-1	This accumulated other comprehensive component is reclassified in Interest expense in our Consolidated Statements of Income. See Note 10, Derivative Financial Instruments, for more information.
	-2	This accumulated other comprehensive component is reclassified in Cost of revenue and General and administrative expenses in our Consolidated Statements of Income. See Note 8, Pension Benefit Obligations, for more information.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Sep. 30, 2014
Stockholders' Equity	'
Stockholders' Equity	'
	16. Stockholders' Equity
	Common Stock Units—Common stock units are only redeemable for common stock. In the event of liquidation of the Company, holders of stock units are entitled to no greater rights than holders of common stock. See also Note 17.

Stock_Plans

Stock Plans	12 Months Ended
	Sep. 30, 2014
Stock Plans	'
Stock Plans	'
	17. Stock Plans
	Defined Contribution Plans—Substantially all permanent employees are eligible to participate in defined contribution plans provided by the Company. Under these plans, participants may make contributions into a variety of funds, including a fund that is fully invested in Company stock. Employees are not required to allocate any funds to Company stock. Employees may generally reallocate their account balances on a daily basis; however, employees classified as insiders are restricted under the Company's insider trading policy.
	Stock compensation expense relating to employer contributions under defined contribution plans for fiscal years ended September 30, 2014, 2013 and 2012 was $14.4 million, $14.6 million and $15.9 million, respectively. Issuances of AECOM common stock related to employee participants' contributions to these defined contribution plans are included as issuances of stock in the accompanying Consolidated Statements of Stockholders' Equity and of Cash Flows.
	Stock Incentive Plans—Under the 2006 Stock Incentive Plan, the Company has up to 19.8 million securities remaining available for future issuance under stock options or up to 9.9 million securities remaining available for restricted stock awards and performance stock awards as of September 30, 2014. Stock options may be granted to employees and non-employee directors with an exercise price not less than the fair market value of the stock on the date of grant. Unexercised options expire seven years after date of grant.
	During the three years in the period ended September 30, 2014, option activity was as follows:
		Number of			Weighted
		Options			Average
		(in millions)			Exercise Price
	Balance, September 30, 2011		2.9		$	21.38
	Granted		—			—
	Exercised		(0.4	)		11.4
	Cancelled		—			26.23
	Balance, September 30, 2012		2.5			22.81
	Granted		—			—
	Exercised		(0.8	)		18.31
	Cancelled		(0.1	)		26.83
	Balance, September 30, 2013		1.6			24.73
	Granted		0.6			31.62
	Exercised		(0.5	)		23.64
	Cancelled		(0.1	)		26.87
	Balance, September 30, 2014		1.6			27.69
	Exercisable as of September 30, 2012		2.1		$	22.07
	Exercisable as of September 30, 2013		1.4			24.51
	Exercisable as of September 30, 2014		0.9			25.16
	The following table summarizes information concerning outstanding and exercisable options as of September 30, 2014:
		Options Outstanding									Options Exercisable
		Number			Weighted		Weighted		Aggregate		Number		Weighted		Weighted
		Outstanding			Average		Average		Intrinsic		Exercisable		Average		Average
		as of			Remaining		Exercise		Value		as of		Remaining		Exercise
		September 30,			Contractual		Price		(in millions)		September 30,		Contractual		Price
		2014			Life						2014		Life
		(in millions)									(in millions)
	Range of Exercise Prices
	$21.01 - $23.94		0.4			1.18	$	23.46	$	4.1		0.4		1.18	$	23.46
	24.45 -  28.67		0.5			2.06		26.24		3.6		0.5		2.06		26.24
	30.96 -  34.00		0.7			9.17		31.65		0.8		—		0.66		32.53
			1.6			4.69		27.69	$	8.5		0.9		1.65		25.16
	The remaining contractual life of options outstanding at September 30, 2014 range from 0.03 to 9.43 years and have a weighted average remaining contractual life of 4.69 years. The aggregate intrinsic value of stock options exercised during the years ended September 30, 2014, 2013 and 2012 was $4.3 million, $7.9 million and $3.9 million, respectively.
	The fair value of the Company's employee stock option awards is estimated on the date of grant. The expected term of awards granted represents the period of time the awards are expected to be outstanding. The risk-free interest rate is based on U.S. Treasury bond rates with maturities equal to the expected term of the option on the grant date. The Company uses historical data as a basis to estimate the probability of forfeitures. The weighted average grant-date fair value of stock options granted during the year ended September 30, 2014 was $7.83.
	The Company grants stock units to employees under the Performance Earnings Program (PEP), whereby units are earned and issued dependent upon meeting established performance objectives and vesting over a three-year period. Additionally, the Company issues restricted stock units, which are earned based on service conditions. The grant date fair value of PEP awards and restricted stock unit awards is that day’s closing market price of the Company’s common stock.  The weighted average grant date fair value of PEP awards was $29.32, $22.27, and $20.58 during the years ended September 30, 2014, 2013 and 2012, respectively.  The weighted average grant date fair value of restricted stock unit awards was $29.60, $22.83, and $20.62 during the years ended September 30, 2014, 2013 and 2012, respectively. Total compensation expense related to these share-based payments including stock options was $34.4 million, $32.6 million and $26.6 million during the years ended September 30, 2014, 2013 and 2012, respectively. Unrecognized compensation expense related to total share-based payments outstanding as of September 30, 2014 was $62.4 million, to be recognized on a straight-line basis over the awards' respective vesting periods which are generally three years.
	Cash flow attributable to tax benefits resulting from tax deductions in excess of compensation cost recognized for those stock options (excess tax benefits) is classified as financing cash flows. Excess tax benefits of $0.7 million, $1.8 million and $1.3 million for the years ended September 30, 2014, 2013 and 2012, respectively, have been classified as financing cash inflows in the Consolidated Statements of Cash Flows.

Income_Taxes

Income Taxes	12 Months Ended
	Sep. 30, 2014
Income Taxes	'
Income Taxes	'
	18. Income Taxes
	Income before income taxes included income (loss) from domestic operations of $138.2 million, $111.8 million and $(89.2) million for fiscal years ended September 30, 2014, 2013 and 2012 and income from foreign operations of $176.6 million, $224.0 million and $106.7 million for fiscal years ended September 30, 2014, 2013 and 2012.
	Income tax expense (benefit) on continuing operations is comprised of:
		Fiscal Year Ended
		September 30,			September 30,			September 30,
		2014			2013			2012
		(in millions)
	Current:
	Federal	$	5.3		$	30.3		$	29.3
	State		3.3			9.9			2.1
	Foreign		46.3			59.7			63.3
	Total current income tax expense		54.9			99.9			94.7
	Deferred:
	Federal		27.7			5.8			(19.2	)
	State		5.6			(10.6	)		0.6
	Foreign		(6.2	)		(2.5	)		(1.7	)
	Total deferred income tax expense (benefit)		27.1			(7.3	)		(20.3	)
	Total income tax expense	$	82		$	92.6		$	74.4
	The major elements contributing to the difference between the U.S. federal statutory rate of 35.0% and the effective tax rate are as follows:
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		Amount			%			Amount			%			Amount			%
		(in millions)
	Tax at federal statutory rate	$	110.2			35	%	$	117.5			35	%	$	6.1			35	%
	State income tax, net of federal benefit		5			1.6			2.5			0.7			1.1			6.3
	U.S. income tax credits and incentives		(3.5	)		(1.1	)		(10.8	)		(3.2	)		(2.9	)		(16.6	)
	Foreign tax rate differential		(22.5	)		(7.2	)		(9.9	)		(2.9	)		(25.4	)		(145.1	)
	Foreign Research and Experimentation credits		(3.6	)		(1.1	)		(3.9	)		(1.1	)		(5.8	)		(33.3	)
	Goodwill impairment		—			—			—			—			101.1			578.3
	Change in uncertain tax positions		(4.5	)		(1.4	)		(7.3	)		(2.2	)		(4.1	)		(23.4	)
	Valuation allowance		6.3			2			1.6			0.5			0.5			2.7
	Domestic production activities deduction		(11.7	)		(3.7	)		(2.6	)		(0.8	)		(1.2	)		(6.8	)
	Nondeductible transaction costs		2.8			0.9			—			—			1.3			7.6
	Other items, net		3.5			1.1			5.5			1.6			3.7			21
	Total income tax expense	$	82			26.1	%	$	92.6			27.6	%	$	74.4			425.7	%
	The deferred tax assets (liabilities) are as follows:
		Fiscal Year Ended
		September 30,			September 30,
		2014			2013
		(in millions)
	Deferred tax assets:
	Compensation and benefit accruals not currently deductible	$	65.5		$	74.7
	Net operating loss carry forwards		69.3			58.1
	Self insurance reserves		48.8			54.7
	Research and Experimentation and other tax credits		34.2			38.3
	Pension liability		59.4			58.5
	Accrued liabilities		63.7			56.1
	Investments in joint ventures/non-controlled subsidiaries		20.7			13.9
	State taxes		1.5			0.9
	Other		4			4.2
	Total deferred tax assets		367.1			359.4
	Deferred tax liabilities:
	Unearned revenue		(122.9	)		(139.3	)
	Depreciation and amortization		(59.2	)		(20.1	)
	Acquired intangible assets		(14.8	)		(15.8	)
	Total deferred tax liabilities		(196.9	)		(175.2	)
	Valuation allowance		(27.1	)		(20.8	)
	Net deferred tax assets	$	143.1		$	163.4
	As of September 30, 2014, the Company has available unused state net operating loss (NOL) carry forwards of $230.6 million and foreign NOL carry forwards of $260.2 million which expire at various dates. In addition, as of September 30, 2014, the Company has unused state research and development credits of $17.5 million and California Enterprise Zone Tax Credits of $4.6 million which can be carried forward indefinitely.
	As of September 30, 2014 and 2013, gross deferred tax assets were $367.1 million and $359.4 million, respectively. The Company has recorded a valuation allowance of approximately $27.1 million and $20.8 million at September 30, 2014 and 2013, respectively, related to state and foreign net operating loss carry forwards and credits. The Company has performed an assessment of positive and negative evidence, including the nature, frequency, and severity of cumulative financial reporting losses in recent years, the future reversal of existing temporary differences, predictability of future taxable income exclusive of reversing temporary differences of the character necessary to realize the asset, relevant carry forward periods, taxable income in carry-back years if carry-back is permitted under tax law, and prudent and feasible tax planning strategies that would be implemented, if necessary, to protect against the loss of the deferred tax asset. Although realization is not assured, based on the Company's assessment, the Company has concluded that it is more likely than not that the remaining gross deferred tax asset (exclusive of deferred tax liabilities) of $340.0 million will be realized and, as such, no additional valuation allowance has been provided.
	As of September 30, 2014 and 2013, the Company has remaining tax-deductible goodwill of $251.6 million and $283.9 million, respectively, resulting from acquisitions. The amortization of this goodwill is deductible over various periods ranging up to 15 years.
	The Company does not provide for U.S. taxes or foreign withholding taxes on undistributed earnings from non-U.S. subsidiaries because such earnings are able to and intended to be reinvested indefinitely. The undistributed earnings are approximately $976.7 million. If undistributed pre-tax earnings were distributed, foreign tax credits could become available under current law to partially or fully reduce the resulting U.S. income tax liability. If such earnings were repatriated, additional tax expense may result, although the calculation of such additional taxes is not practicable.
As of September 30, 2014 and 2013, the Company had a liability for unrecognized tax benefits, including potential interest and penalties, net of related tax benefit, totaling $52.6 million and $60.2 million, respectively. The gross unrecognized tax benefits as of September 30, 2014 and 2013 were $47.5 million and $53.7 million, respectively, excluding interest, penalties, and related tax benefit. Of the $47.5 million, approximately $28.6 million would be included in the effective tax rate if recognized in the fiscal year ended September 30, 2014. The adoption of ASC 805, "Accounting for Business Combinations," at the beginning of the fiscal year ended September 30, 2010 changed the treatment of the reversal of unrecognized tax benefits related to acquired companies which prior to adoption of ASC 805 would have impacted goodwill, but after the adoption of ASC 805, results in the recognition of income tax benefit. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows:
	Fiscal Year Ended
	September 30,			September 30,
	2014			2013
	(in millions)
Balance at the beginning of the year	$	53.7		$	55.8
Gross increase in prior years' tax positions		3.3			7.2
Gross decrease in prior years' tax positions		(7.6	)		(5.6	)
Decrease due to settlement with tax authorities		(2.0	)		(1.6	)
Gross increase in current period's tax positions		2.2			3.8
Lapse of statute of limitations		(2.1	)		(5.9	)
Balance at the end of the year	$	47.5		$	53.7
The Company classifies interest and penalties related to uncertain tax positions within the income tax expense line in the accompanying consolidated statements of operations. At September 30, 2014, the accrued interest and penalties were $6.2 million and $2.9 million, respectively, excluding any related income tax benefits. As of September 30, 2013, the accrued interest and penalties were $7.3 million and $2.7 million, respectively, excluding any related income tax benefits.
The Company files income tax returns in numerous tax jurisdictions, including the U.S., and numerous U.S. states and non-U.S. jurisdictions around the world. The statute of limitations varies by jurisdiction in which the Company operates. Because of the number of jurisdictions in which the Company files tax returns, in any given year the statute of limitations in certain jurisdictions may expire without examination within the 12-month period from the balance sheet date.
The Company is currently under examination by the U.S. Internal Revenue Service for the fiscal years ended September 30, 2010 and September 30, 2011. With a few exceptions, the Company is no longer subject to U.S. state or non-U.S. income tax examinations by tax on authorities for years before fiscal year 2009. The Company anticipates that some of the audits may be concluded in the foreseeable future, including in fiscal year ending September 30, 2015. Based on the status of these audits, it is reasonably possible that the conclusion of the audits may result in a reduction of unrecognized tax benefits. It is not possible to estimate the impact of any change at this time.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Sep. 30, 2014
Earnings Per Share	'
Earnings Per Share	'
	19. Earnings Per Share
	Basic earnings per share (EPS) excludes dilution and is computed by dividing net income available for common stockholders by the weighted average number of common shares outstanding for the period. Diluted EPS is computed by dividing net income by the weighted average number of common shares outstanding and potential common shares for the period. The Company includes as potential common shares the weighted average dilutive effects of outstanding stock options and restricted stock units using the treasury stock method. The computation of diluted loss per share for the year ended September 30, 2012 excludes 0.7 million of potential common shares due to their antidilutive effect.
	The following table sets forth a reconciliation of the denominators of basic and diluted earnings per share:
		Fiscal Year Ended
		September 30,		September 30,		September 30,
		2014		2013		2012
		(in millions)
	Denominator for basic earnings per share		97.2		100.6		111.9
	Potential common shares		1.5		1.3		—
	Denominator for diluted earnings per share		98.7		101.9		111.9
	As discussed in Note 3, EPS includes the effect of repurchased shares. For the years ended September 30, 2014 and 2013, options excluded from the calculation of potential common shares were not significant.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Sep. 30, 2014
Commitments and Contingencies	'
Commitments and Contingencies	'
	20. Commitments and Contingencies
	The Company records amounts representing its probable estimated liabilities relating to claims, guarantees, litigation, audits and investigations. The Company relies in part on qualified actuaries to assist it in determining the level of reserves to establish for insurance-related claims that are known and have been asserted against it, and for insurance-related claims that are believed to have been incurred based on actuarial analysis, but have not yet been reported to the Company's claims administrators as of the respective balance sheet dates. The Company includes any adjustments to such insurance reserves in its consolidated results of operations.
	The Company is a defendant in various lawsuits arising in the normal course of business. In the opinion of management, based upon current information and discussions with counsel, with the exception of the matters noted below, the ultimate resolution of these matters will not have a material adverse effect on its consolidated balance sheet or statements of operations or cash flows.
	In some instances, the Company guarantees that a project, when complete, will achieve specified performance standards. If the project subsequently fails to meet guaranteed performance standards, the Company may either incur additional costs or be held responsible for the costs incurred by the client to achieve the required performance standards. At September 30, 2014, the Company was contingently liable in the amount of approximately $313.1 million under standby letters of credit issued primarily in connection with general and professional liability insurance programs and for payment of performance guarantees.
	In the ordinary course of business, the Company enters into various agreements providing financial or performance assurances to clients on behalf of certain unconsolidated partnerships, joint ventures and other jointly executed contracts. These agreements are entered into primarily to support the project execution commitments of these entities. In addition, in connection with the investment activities of AECOM Capital, we provide guarantees of certain obligations, including guarantees for completion of projects, repayment of debt, environmental indemnity obligations and acts of willful misconduct. The guarantees have various expiration dates. The maximum potential payment amount of an outstanding performance guarantee is the remaining cost of work to be performed by or on behalf of third parties. Generally, under joint venture arrangements, if a partner is financially unable to complete its share of the contract, the other partner(s) will be required to complete those activities. The Company generally only enters into joint venture arrangements with partners who are reputable, financially sound and who carry appropriate levels of surety bonds for the project in order to adequately assure completion of their assignments. The Company does not expect that these guarantees will have a material adverse effect on its consolidated balance sheet or statements of operations or cash flows.
	Tishman Inquiry
	The U.S. Attorney's Office for the Eastern District of New York (USAO) has informed the Company's subsidiary Tishman Construction Corporation (TCC) that, in connection with a wage and hour investigation of several New York area contractors, the USAO is investigating potential improper overtime payments to union workers on projects managed by TCC and other contractors in New York dating back to 1999. TCC, which was acquired by the Company in 2010, has cooperated fully with the investigation and, as of this date, no actions have been filed.
	AECOM Australia
	In 2005 and 2006, the Company's main Australian subsidiary, AECOM Australia Pty Ltd (AECOM Australia), performed a traffic forecast assignment for a client consortium as part of the client's project to design, build, finance and operate a tolled motorway tunnel in Australia. To fund the motorway's design and construction, the client formed certain special purpose vehicles (SPVs) that raised approximately $700 million Australian dollars through an initial public offering (IPO) of equity units in 2006 and approximately an additional $1.4 billion Australian dollars in long term bank loans. The SPVs went into insolvency administrations in February 2011.
	KordaMentha, the receivers for the SPVs (the RCM Applicants), caused a lawsuit to be filed against AECOM Australia by the RCM Applicants in the Federal Court of Australia on May 14, 2012. Portigon AG (formerly WestLB AG), one of the lending banks to the SPVs, filed a lawsuit in the Federal Court of Australia against AECOM Australia on May 18, 2012. Separately, a class action lawsuit, which has been amended to include approximately 770 of the IPO investors, was filed against AECOM Australia in the Federal Court of Australia on May 31, 2012.
	All of the lawsuits claim damages that purportedly resulted from AECOM Australia's role in connection with the above described traffic forecast. The RCM Applicants have claimed damages of approximately $1.68 billion Australian dollars (including interest, as of March 31, 2014). The damages claimed by Portigon as of June 17, 2014 were also recently quantified at approximately $76 million Australian dollars (including interest). The Company believes this claim is duplicative of damages already included in the RCM Applicants' claim to the extent Portigon receives a portion of the RCM Applicants' recovery. The class action applicants claim that they represent investors who acquired approximately $155 million Australian dollars of securities.
	AECOM Australia disputes the claimed entitlements to damages asserted by all applicants and is vigorously defending the claims brought against it. The likely resolution of these matters cannot be reasonably determined at this time. However, if these matters are not resolved in AECOM Australia's favor then, depending upon the outcome, such resolution could have a material adverse effect on the Company's results of operations.

Reportable_Segments_and_Geogra

Reportable Segments and Geographic Information	12 Months Ended
	Sep. 30, 2014
Reportable Segments and Geographic	'
Reportable Segments and Geographic Information	'
	21. Reportable Segments and Geographic Information
	The Company's operations are organized into two reportable segments: Professional Technical Services (PTS) and Management Support Services (MSS). The Company's PTS reportable segment delivers planning, consulting, architectural and engineering design, and program and construction management services to commercial and government clients worldwide. The Company's MSS reportable segment provides program and facilities management and maintenance, training, logistics, consulting, and technical assistance and systems integration services, primarily for agencies of the U.S. government. These reportable segments are organized by the types of services provided, the differing specialized needs of the respective clients, and how the Company manages its business. The Company has aggregated operating segments into its PTS reportable segment based on their similar characteristics, including similar long term financial performance, the nature of services provided, internal processes for delivering those services, and types of customers.
	Management internally analyzes the results of its operations using several non-GAAP measures. A significant portion of the Company's revenues relates to services provided by subcontractors and other non-employees that it categorizes as other direct costs. Other direct costs are segregated from cost of revenues resulting in revenue, net of other direct costs, which is a measure of work performed by Company employees. The Company has included information on revenue, net of other direct costs, as it believes that it is useful to view its revenue exclusive of costs associated with external service providers.
	The following tables set forth unaudited summarized financial information concerning the Company's reportable segments:
	Reportable Segments:		Professional			Management			Corporate			Total
			Technical			Support
			Services			Services
			(in millions)
	Fiscal Year Ended September 30, 2014:
	Revenue		$	7,609.90		$	746.9		$	—		$	8,356.80
	Revenue, net of other direct costs(1)			4,462.70			392.9			—			4,855.60
	Gross profit			365.2			38			—			403.2
	Equity in earnings of joint ventures			41.4			16.5			—			57.9
	General and administrative expenses			—			—			(80.9	)		(80.9	)
	Acquisition and integration expenses			—			—			(27.3	)		(27.3	)
	Operating income (loss)			406.6			54.5			(108.2	)		352.9
	Segment assets			5,366.00			392.4			365			6,123.40
	Gross profit as a % of revenue			4.8	%		5.1	%					4.8	%
	Gross profit as a % of revenue, net of other direct costs(1)			8.2	%		9.7	%					8.3	%
	Fiscal Year Ended September 30, 2013:
	Revenue		$	7,242.90		$	910.6		$	—		$	8,153.50
	Revenue, net of other direct costs(1)			4,416.40			560.6			—			4,977.00
	Gross profit			416.9			33.1			—			450
	Equity in earnings of joint ventures			12.3			12			—			24.3
	General and administrative expenses			—			—			(97.3	)		(97.3	)
	Operating income (loss)			429.2			45.1			(97.3	)		377
	Segment assets			4,827.50			598			240.1			5,665.60
	Gross profit as a % of revenue			5.8	%		3.6	%					5.5	%
	Gross profit as a % of revenue, net of other direct costs(1)			9.4	%		5.9	%					9	%
	Fiscal Year Ended September 30, 2012:
	Revenue		$	7,276.90		$	941.3		$	—		$	8,218.20
	Revenue, net of other direct costs(1)			4,607.30			576.6			—			5,183.90
	Gross profit			423.8			(1.9	)		—			421.9
	Equity in earnings of joint ventures			16.8			31.8			—			48.6
	General and administrative expenses			—			—			(80.9	)		(80.9	)
	Goodwill impairment			(155.0	)		(181.0	)		—			(336.0	)
	Operating income (loss)			285.6			(151.1	)		(80.9	)		53.6
	Gross profit as a % of revenue			5.8			(0.2						5.1
					%			)%						%
	Gross profit as a % of revenue, net of other direct costs(1)			9.2	%		(0.3	)%					8.1	%
	-1	Non-GAAP measure.
	Geographic Information:
			Fiscal Year Ended
			September 30, 2014						September 30, 2013						September 30, 2012
			Revenue			Long-Lived			Revenue			Long-Lived			Revenue		Long-Lived
						Assets						Assets					Assets
			(in millions)
	United States		$	4,933.7			1,603.7		$	4,829.6			1,477.3		$	4,756.0		1,496.8
	Asia Pacific			1,338.2			340.5			1,507.2			361.0			1,715.1		374.9
	Canada			561.1			146.7			712.0			168.4			708.8		189.2
	Europe			788.2			270.8			599.4			267.2			608.2		243.6
	Other foreign countries			735.6			209.5			505.3			116.6			430.1		85.8
	Total		$	8,356.8			2,571.2		$	8,153.5			2,390.5		$	8,218.2		2,390.3
	The Company attributes revenue by geography based on the external customer's country of origin. Long-lived assets consist of noncurrent assets excluding deferred tax assets.

Major_Clients

Major Clients	12 Months Ended
	Sep. 30, 2014
Major Clients	'
Major Clients	'
	22. Major Clients
	Other than the U.S. federal government, no single client accounted for 10% or more of the Company's revenue in any of the past five fiscal years. Approximately 15%, 18% and 18% of the Company's revenue was derived through direct contracts with agencies of the U.S. federal government in the years ended September 30, 2014, 2013 and 2012, respectively. One of these contracts accounted for approximately 3%, 4% and 4% of the Company's revenue in the years ended September 30, 2014, 2013 and 2012, respectively.

Quarterly_Financial_Informatio

Quarterly Financial Information-Unaudited	12 Months Ended
	Sep. 30, 2014
Quarterly Financial Information-Unaudited	'
Quarterly Financial Information-Unaudited	'
	23. Quarterly Financial Information—Unaudited
	In the opinion of management, the following unaudited quarterly data reflects all adjustments necessary for a fair statement of the results of operations. All such adjustments are of a normal recurring nature.
	Fiscal Year 2014:	First			Second			Third			Fourth
		Quarter			Quarter			Quarter			Quarter
		(in millions, except per share data)
	Revenue	$	1,953.90		$	1,872.20		$	1,968.20		$	2,562.50
	Cost of revenue		1,875.70			1,784.80			1,859.70			2,433.40
	Gross profit		78.2			87.4			108.5			129.1
	Equity in earnings of joint ventures		36.1			7.4			6			8.4
	General and administrative expenses		(23.9	)		(26.4	)		(15.1	)		(15.5	)
	Acquisition and integration expenses		—			—			(7.8	)		(19.5	)
	Income from operations		90.4			68.4			91.6			102.5
	Other income (expenses)		—			(0.2	)		1			1.9
	Interest expense		(10.4	)		(10.5	)		(9.8	)		(10.1	)
	Income before income tax expense		80			57.7			82.8			94.3
	Income tax expense		23.5			15.2			13.7			29.6
	Net income		56.5			42.5			69.1			64.7
	Noncontrolling interest in income of consolidated subsidiaries, net of tax		(0.1	)		(2.3	)		0.1			(0.6	)
	Net income attributable to AECOM	$	56.4		$	40.2		$	69.2		$	64.1
	Net income attributable to AECOM per share:
	Basic	$	0.59		$	0.41		$	0.71		$	0.65
	Diluted	$	0.58		$	0.41		$	0.7		$	0.64
	Weighted average common shares outstanding:
	Basic		96.3			97			97.5			98.1
	Diluted		97.6			98.3			99			99.7
	Fiscal Year 2013:	First			Second			Third			Fourth
		Quarter			Quarter			Quarter			Quarter
		(in millions, except per share data)
	Revenue	$	2,017.30		$	1,989.60		$	2,067.50		$	2,079.10
	Cost of revenue		1,939.20			1,889.70			1,935.70			1,938.90
	Gross profit		78.1			99.9			131.8			140.2
	Equity in earnings of joint ventures		5.9			7.9			4.1			6.4
	General and administrative expenses		(22.1	)		(27.3	)		(24.0	)		(23.9	)
	Income from operations		61.9			80.5			111.9			122.7
	Other income		0.7			0.1			1.2			1.5
	Interest expense		(10.9	)		(11.9	)		(11.7	)		(10.2	)
	Income before income tax expense		51.7			68.7			101.4			114
	Income tax expense		12.7			14			30.1			35.8
	Net income		39			54.7			71.3			78.2
	Noncontrolling interest in income of consolidated subsidiaries, net of tax		(0.9	)		(0.9	)		(0.5	)		(1.7	)
	Net income attributable to AECOM	$	38.1		$	53.8		$	70.8		$	76.5
	Net income attributable to AECOM per share:
	Basic	$	0.36		$	0.54		$	0.71		$	0.78
	Diluted	$	0.36		$	0.53		$	0.7		$	0.77
	Weighted average common shares outstanding:
	Basic		104.8			100.4			99.3			98
	Diluted		105.5			101.8			100.8			99.7

Subsequent_Events

Subsequent Events	12 Months Ended
	Sep. 30, 2014
Subsequent Event	'
Subsequent Event	'
	24. Subsequent Events
	Acquisition of URS Corporation
	On October 17, 2014, the Company completed the acquisition of the U.S. headquartered URS Corporation (URS), a leading international provider of engineering, construction, and technical services, by purchasing 100% of the outstanding shares of URS common stock. The Company paid a total consideration of approximately $2.3 billion in cash and issued approximately $1.6 billion of AECOM common stock to the former stockholders and certain equity award holders of URS. In connection with the acquisition, the Company also assumed URS's senior notes totaling $1.0 billion, and subsequently repaid in full URS's $0.6 billion 2011 term loan and URS's $0.1 billion revolving line of credit. Upon the occurrence of a change in control of URS, the URS senior noteholders had a right to redeem their notes at a cash price equal to 101% of the principal amount of the notes. The acquisition of URS was considered a change in control of URS and, as a result on October 24, 2014, the Company purchased $0.6 billion of URS's senior notes from the noteholders.
	Senior Unsecured Notes
	On October 6, 2014, the Company completed a private placement offering of $800,000,000 aggregate principal amount of its 5.750% Senior Notes due 2022 (the 2022 Notes) and $800,000,000 aggregate principal amount of its 5.875% Senior Notes due 2024 (the 2024 Notes and, together with the 2022 Notes, the Notes).
	At any time prior to October 15, 2017, the Company may redeem all or part of the 2022 Notes, at a redemption price equal to 100% of their principal amount, plus a "make whole" premium as of the redemption date, and accrued and unpaid interest (subject to the rights of holders of record on the relevant record date to receive interest due on the relevant interest payment date). In addition, at any time prior to October 15, 2017, the Company may redeem up to 35% of the original aggregate principal amount of the 2022 Notes with the proceeds of one or more equity offerings, at a redemption price equal to 105.750%, plus accrued and unpaid interest. Furthermore, at any time on or after October 15, 2017, the Company may redeem the 2022 Notes, in whole or in part, at once or over time, at the specified redemption prices plus accrued and unpaid interest thereon to the redemption date. At any time prior to July 15, 2024, the Company may redeem on one or more occasions all or part of the 2024 Notes at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) a "make-whole" premium as of the date of the redemption, plus any accrued and unpaid interest to the date of redemption. In addition, on or after July 15, 2024, the 2024 Notes may be redeemed by the Company at a redemption price of 100% of the principal amount thereof, plus accrued and unpaid interest to the date of redemption.
	The indenture contains customary events of default, including, among other things, payment default, exchange default, failure to provide certain notices thereunder and certain provisions related to bankruptcy events. The indenture also contains customary negative covenants.
	In connection with the offering of the Notes, the Company and the guarantors entered into a Registration Rights Agreement, dated as of October 6, 2014 and agreed to use commercially reasonable efforts to (i) file with the U.S. Securities and Exchange Commission (SEC) a registration statement relating to the registered exchange offer (the Exchange Offer) to exchange the Notes for a new series of the Company's exchange notes having terms substantially identical in all material respects to, and in the same aggregate principal amount as the Notes, (ii) cause the Exchange Offer registration statement to be declared effective by the SEC on or prior to the 390th day following October 6, 2014 (or if such 390th day is not a business day, the next succeeding business day (the Exchange Date)), (iii) cause the Exchange Offer registration statement to be effective continuously and keep the exchange offer open for a period not less than 30 days after the date notice of the exchange offer is mailed to the holders of the Notes and (iv) cause the Exchange Offer to be consummated in no event later than the Exchange Date.
	Under certain circumstances, the Company and the guarantors have agreed to use their commercially reasonable efforts to (i) file a shelf registration statement relating to the resale of the Notes on or prior to the Exchange Date (such date being the Shelf Filing Deadline), (ii) cause the shelf registration statement to be declared effective not later than the 60th day after the Shelf Filing Deadline (or if such 60th day is not a business day, the next succeeding business day) and (iii) keep such shelf registration continuously effective until two years after its effective date (or such shorter period that will terminate when all the Notes covered thereby have been sold pursuant thereto).
	If the Company fails to meet any of these targets, the annual interest rate on the Notes will increase by 0.25%, and will increase by an additional 0.25% for each subsequent 90-day period during which the default continues, up to a maximum additional interest rate of 1.0% per year. If the Company cures the default, the interest rate on the Notes will revert to the original level.
	Credit Agreement; Security Agreement
	In connection with the acquisition of URS, on October 17, 2014, the Company entered into a new credit agreement (the Credit Agreement). The Credit Agreement consists of (i) a term loan A facility in an aggregate principal amount of $1.925 billion, (ii) a term loan B facility in an aggregate principal amount of $0.76 billion, (iii) a revolving credit facility in an aggregate principal amount of $1.05 billion, and (iv) an incremental performance letter of credit facility in an aggregate principal amount of $500 million. These facilities under the Credit Agreement may be increased by an additional amount of up to $500 million.
	Pursuant to the Credit Agreement, certain subsidiaries of the Company (the Guarantors) have guaranteed the obligations of the borrowers under the Credit Agreement. The borrowers' obligations under the Credit Agreement are secured by a lien on substantially all of the assets of the Company and the Guarantors pursuant to a security and pledge agreement (the Security Agreement). The collateral under the Security Agreement is subject to release upon fulfillment of certain conditions specified in the Credit Agreement and Security Agreement.
	The Credit Agreement and related loan documents contain covenants that limit the ability of the Company and certain of its subsidiaries to, among other things:
	•	create, incur, assume, or suffer to exist liens;
	•	incur or guarantee indebtedness;
	•	pay dividends or repurchase stock;
	•	enter into transactions with affiliates;
	•	consummate asset sales, acquisitions or mergers;
	•	enter into certain type of burdensome agreements; or
	•	make investments.
	The Credit Agreement also requires compliance with certain financial covenants, including a maximum consolidated leverage ratio and a minimum consolidated interest coverage ratio, in each case calculated as set forth in the Credit Agreement.
	The Credit Agreement contains customary events of default, including:
	•	a change of control;
	•	failure to make required payments;
	•	failure to comply with certain agreements or covenants;
	•	failure to pay, or acceleration of, certain other indebtedness;
	•	certain events of bankruptcy and insolvency; and
	•	failure to pay certain judgments.
	The Credit Agreement replaced (i) the Company's Second Amended and Restated Credit Agreement, dated as of June 7, 2013, and (ii) the Company's Fourth Amended and Restated Credit Agreement, dated as of January 29, 2014, which such prior facilities were terminated and repaid in full on October 17, 2014 in connection with the entry into the Credit Agreement.
	In connection with the consummation of the URS acquisition on October 17, 2014, AECOM also prepaid in full $300 million face value (plus accrued interest as well as a prepayment penalty of $56 million) of its 5.43% Series A notes due July 2020 and 1.00% Senior Discount Notes, Series B, due July 2022. Borrowings under the Credit Agreement were used to prepay the Senior Notes.
	URS Senior Notes
	The URS senior notes are general unsecured senior obligations of AECOM Global II, LLC (as successor in interest to URS) and URS Fox US LP and are fully and unconditionally guaranteed on a joint-and-several basis by certain former URS domestic subsidiary guarantors.

Schedule_II_Valuation_and_Qual

Schedule II: Valuation and Qualifying Accounts	12 Months Ended
	Sep. 30, 2014
Schedule II: Valuation and Qualifying Accounts	'
Schedule II: Valuation and Qualifying Accounts	'
	Schedule II: Valuation and Qualifying Accounts
	(amounts in millions)
			Balance at		Additions		Deductions(a)			Other and		Balance at
			Beginning		Charged to Cost					Foreign		the End of
			of Year		of Revenue					Exchange Impact		the Year
	Allowance for Doubtful Accounts
	Fiscal Year 2014			86.4		17.3		(38.4			6.8		72.1
			$		$		$		)	$		$
	Fiscal Year 2013			112.8		18.3		(45.5	)		0.8		86.4
	Fiscal Year 2012			120.2		28.7		(37.7	)		1.6		112.8
	(a)	Primarily relates to accounts written-off and recoveries

Significant_Accounting_Policie1

Significant Accounting Policies (Policies)	12 Months Ended
	Sep. 30, 2014
Significant Accounting Policies	'
Fiscal Year	'
	Fiscal Year—The Company reports results of operations based on 52 or 53-week periods ending on the Friday nearest September 30. For clarity of presentation, all periods are presented as if the year ended on September 30. Fiscal years 2014, 2013 and 2012 contained 53, 52 and 52 weeks, respectively, and ended on October 3, September 27, and September 28, respectively.
Use of Estimates	'
	Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the United States (GAAP) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. The more significant estimates affecting amounts reported in the consolidated financial statements relate to revenues under long-term contracts and self-insurance accruals. Actual results could differ from those estimates.
Principles of Consolidation and Presentation	'
	Principles of Consolidation and Presentation—The consolidated financial statements include the accounts of all majority-owned subsidiaries and material joint ventures in which the Company is the primary beneficiary. All inter-company accounts have been eliminated in consolidation. Also see Note 7 regarding joint ventures and variable interest entities.
Revenue Recognition	'
	Revenue Recognition—The Company generally utilizes a cost-to-cost approach in applying the percentage-of-completion method of revenue recognition. Under this approach, revenue is earned in proportion to total costs incurred, divided by total costs expected to be incurred. Recognition of revenue and profit is dependent upon a number of factors, including the accuracy of a variety of estimates made at the balance sheet date, engineering progress, materials quantities, the achievement of milestones, penalty provisions, labor productivity and cost estimates made at the balance sheet date. Due to uncertainties inherent in the estimation process, actual completion costs may vary from estimates. If estimated total costs on contracts indicate a loss, the Company recognizes that estimated loss in the period the estimated loss first becomes known.
	In the course of providing its services, the Company routinely subcontracts for services and incurs other direct costs on behalf of its clients. These costs are passed through to clients and, in accordance with industry practice and GAAP, are included in the Company's revenue and cost of revenue. Because subcontractor services and other direct costs can change significantly from project to project and period to period, changes in revenue may not be indicative of business trends. These other direct costs for the years ended September 30, 2014, 2013 and 2012 were $3.5 billion, $3.2 billion and $3.0 billion, respectively.
Government Contract Matters	'
	Government Contract Matters—The Company's federal government and certain state and local agency contracts are subject to, among other regulations, regulations issued under the Federal Acquisition Regulations (FAR). These regulations can limit the recovery of certain specified indirect costs on contracts and subjects the Company to ongoing multiple audits by government agencies such as the Defense Contract Audit Agency (DCAA). In addition, most of the Company's federal and state and local contracts are subject to termination at the discretion of the client.
	Audits by the DCAA and other agencies consist of reviews of the Company's overhead rates, operating systems and cost proposals to ensure that the Company accounted for such costs in accordance with the Cost Accounting Standards of the FAR (CAS). If the DCAA determines the Company has not accounted for such costs consistent with CAS, the DCAA may disallow these costs. There can be no assurance that audits by the DCAA or other governmental agencies will not result in material cost disallowances in the future.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents—The Company's cash equivalents include highly liquid investments which have an initial maturity of three months or less.
Allowance for Doubtful Accounts	'
	Allowance for Doubtful Accounts—The Company records its accounts receivable net of an allowance for doubtful accounts. This allowance for doubtful accounts is estimated based on management's evaluation of the contracts involved and the financial condition of its clients. The factors the Company considers in its contract evaluations include, but are not limited to:
	•	Client type—federal or state and local government or commercial client;
	•	Historical contract performance;
	•	Historical collection and delinquency trends;
	•	Client credit worthiness; and
	•	General economic conditions.
Derivative Financial Instruments	'
	Derivative Financial Instruments—The Company accounts for its derivative instruments as either assets or liabilities and carries them at fair value.
	For derivative instruments that hedge the exposure to variability in expected future cash flows that are designated as cash flow hedges, the effective portion of the gain or loss on the derivative instrument is reported as a component of accumulated other comprehensive income in stockholders' equity and reclassified into income in the same period or periods during which the hedged transaction affects earnings. The ineffective portion of the gain or loss on the derivative instrument, if any, is recognized in current income. To receive hedge accounting treatment, cash flow hedges must be highly effective in offsetting changes to expected future cash flows on hedged transactions.
	The net gain or loss on the effective portion of a derivative instrument that is designated as an economic hedge of the foreign currency translation exposure generated by the re-measurement of certain assets and liabilities denominated in a non-functional currency in a foreign operation is reported in the same manner as a foreign currency translation adjustment. Accordingly, any gains or losses related to these derivative instruments are recognized in current income.
	Derivatives that do not qualify as hedges are adjusted to fair value through current income.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments—The Company determines the fair values of its financial instruments, including short-term investments, debt instruments and derivative instruments, and pension and post-retirement plan assets based on inputs or assumptions that market participants would use in pricing an asset or a liability. The Company categorizes its instruments using a valuation hierarchy for disclosure of the inputs used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument; Level 3 inputs are unobservable inputs based on the Company's assumptions used to measure assets and liabilities at fair value. The classification of a financial asset or liability within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
	The carrying amounts of cash and cash equivalents, accounts receivable and accounts payable approximate fair value because of the short maturities of these instruments. The carrying amount of the revolving credit facility approximates fair value because the interest rates are based upon variable reference rates. See also Notes 9 and 11.
	The Company's fair value measurement methods may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Although the Company believes its valuation methods are appropriate and consistent with those used by other market participants, the use of different methodologies or assumptions to determine fair value could result in a different fair value measurement at the reporting date.
Property and Equipment	'
	Property and Equipment—Property and equipment are recorded at cost and are depreciated over their estimated useful lives using the straight-line method. Expenditures for maintenance and repairs are expensed as incurred. Typically, estimated useful lives range from three to ten years for equipment, furniture and fixtures. Leasehold improvements are amortized on a straight-line basis over the shorter of their estimated useful lives or the remaining terms of the underlying lease agreement.
Long-lived Assets	'
	Long-lived Assets—Long-lived assets to be held and used are reviewed for impairment whenever events or circumstances indicate that the assets may be impaired. For assets to be held and used, impairment losses are recognized based upon the excess of the asset's carrying amount over the fair value of the asset. For long-lived assets to be disposed, impairment losses are recognized at the lower of the carrying amount or fair value less cost to sell.
Goodwill and Acquired Intangible Assets	'
	Goodwill and Acquired Intangible Assets—Goodwill represents the excess of amounts paid over the fair value of net assets acquired from an acquisition. In order to determine the amount of goodwill resulting from an acquisition, the Company performs an assessment to determine the value of the acquired company's tangible and identifiable intangible assets and liabilities. In its assessment, the Company determines whether identifiable intangible assets exist, which typically include backlog and customer relationships. Intangible assets are amortized over the period in which the contractual or economic benefits of the intangible assets are expected to be realized.
	The Company tests goodwill for impairment annually for each reporting unit in the fourth quarter of the fiscal year, and between annual tests if events occur or circumstances change which suggest that goodwill should be evaluated. Such events or circumstances include significant changes in legal factors and business climate, recent losses at a reporting unit, and industry trends, among other factors. A reporting unit is defined as an operating segment or one level below an operating segment. The Company's impairment tests are performed at the operating segment level as they represent the Company's reporting units.
	The impairment test is a two-step process. During the first step, the Company estimates the fair value of the reporting unit using income and market approaches, and compares that amount to the carrying value of that reporting unit. In the event the fair value of the reporting unit is determined to be less than the carrying value, a second step is required. The second step requires the Company to perform a hypothetical purchase allocation for that reporting unit and to compare the resulting current implied fair value of the goodwill to the current carrying value of the goodwill for that reporting unit. In the event that the current implied fair value of the goodwill is less than the carrying value, an impairment charge is recognized. See also Note 4.
Pension Plans	'
	Pension Plans—The Company has certain defined benefit pension plans. The Company calculates the market-related value of assets, which is used to determine the return-on-assets component of annual pension expense and the cumulative net unrecognized gain or loss subject to amortization. This calculation reflects the Company's anticipated long-term rate of return and amortization of the difference between the actual return (including capital, dividends, and interest) and the expected return over a five-year period. Cumulative net unrecognized gains or losses that exceed 10% of the greater of the projected benefit obligation or the market related value of plan assets are subject to amortization.
Insurance Reserves	'
	Insurance Reserves—The Company maintains insurance for certain insurable business risks. Insurance coverage contains various retention and deductible amounts for which the Company accrues a liability based upon reported claims and an actuarially determined estimated liability for certain claims incurred but not reported. It is the Company's policy not to accrue for any potential legal expense to be incurred in defending the Company's position. The Company believes that its accruals for estimated liabilities associated with professional and other liabilities are sufficient and any excess liability beyond the accrual is not expected to have a material adverse effect on the Company's results of operations or financial position.
Foreign Currency Translation	'
	Foreign Currency Translation—The Company's functional currency is the U.S. dollar. Results of operations for foreign entities are translated to U.S. dollars using the average exchange rates during the period. Assets and liabilities for foreign entities are translated using the exchange rates in effect as of the date of the balance sheet. Resulting translation adjustments are recorded as a foreign currency translation adjustment into other accumulated comprehensive income/(loss) in stockholders' equity.
	The Company uses foreign currency forward contracts from time to time to mitigate foreign currency risk. The Company limits exposure to foreign currency fluctuations in most of its contracts through provisions that require client payments in currencies corresponding to the currency in which costs are incurred. As a result of this natural hedge, the Company generally does not need to hedge foreign currency cash flows for contract work performed. The functional currency of all significant foreign operations is the respective local currency.
Noncontrolling Interests	'
	Noncontrolling interests— Noncontrolling interests represent the equity investments of the minority owners in our joint ventures and other subsidiary entities that we consolidate in our financial statements.
Income Taxes	'
	Income Taxes—The Company files a consolidated federal income tax return and combined / consolidated state tax returns and separate company state tax returns. The Company accounts for certain income and expense items differently for financial reporting and income tax purposes. Deferred tax assets and liabilities are determined based on the difference between the financial statement and tax basis of assets and liabilities, applying enacted statutory tax rates in effect for the year in which the differences are expected to reverse. In determining the need for a valuation allowance, management reviews both positive and negative evidence, including the nature, frequency, and severity of cumulative financial reporting losses in recent years, the future reversal of existing temporary differences, predictability of future taxable income exclusive of reversing temporary differences of the character necessary to realize the asset, relevant carry forward periods, taxable income in carry-back years if carry-back is permitted under tax law, and prudent and feasible tax planning strategies that would be implemented, if necessary, to protect against the loss of the deferred tax asset. Based upon management's assessment of all available evidence, the Company has concluded that it is more likely than not that the deferred tax assets, net of valuation allowance, will be realized.
	In July 2013, the FASB issued new accounting guidance that requires the presentation of unrecognized tax benefits as a reduction of the deferred tax assets, when a net operating loss carryforward, a similar tax loss, or a tax credit carryforward exists at the reporting date. This new guidance was effective for annual reporting periods beginning on or after December 15, 2013 and subsequent interim periods. This guidance is effective for the Company's fiscal year beginning October 1, 2014 and it is not expected to have a material impact on the Company's consolidated financial statements.
Acquisition and Integration Expenses	'
	Acquisition and Integration Expenses—Acquisition and integration expenses are comprised of transaction costs, professional fees, and personnel costs, including due diligence and integration activities, primarily related to the acquisition of URS Corporation (Note 24).

Business_Acquisitions_Goodwill1

Business Acquisitions, Goodwill and Intangible Assets (Tables)	12 Months Ended
	Sep. 30, 2014
Business Acquisitions, Goodwill, and Intangible Assets	'
Schedule of estimated fair values of the assets acquired and liabilities assumed, as of the acquisition dates	'
		Fiscal Year Ended
		September 30,			September 30,			September 30,
		2014			2013			2012
		(in millions)
	Cash acquired	$	17.1		$	20.1		$	1.9
	Other current assets		256.2			41.5			7.8
	Goodwill		72.7			72.6			10.5
	Intangible assets		11.9			9.4			1.5
	Other non-current assets		16.5			8.6			3.3
	Current liabilities		(274.1	)		(54.9	)		(8.8	)
	Non-current liabilities		(11.8	)		(15.3	)		(0.8	)
	Net assets acquired	$	88.5		$	82		$	15.4
Schedule of acquired intangible assets from acquisitions	'
		Fiscal Year Ended
		September 30,			September 30,			September 30,
		2014			2013			2012
		(in millions)
	Backlog	$	5.8		$	4.2		$	0.7
	Customer relationships		4.6			5.2			0.8
	Trademark / tradename		1.5			—			—
	Total intangible assets	$	11.9		$	9.4		$	1.5
Schedule of consideration for acquisitions	'
		Fiscal Year Ended
		September 30,			September 30,			September 30,
		2014			2013			2012
		(in millions)
	Cash paid	$	70.2		$	62.1		$	14.5
	Promissory notes		18.3			5.6			—
	Equity issued		—			14.3			0.9
	Total consideration	$	88.5		$	82.0		$	15.4
Schedule of market multiples used in the goodwill impairment evaluation process	'
		September 30,
		2012			2011
	Market multiple of revenue:
	EMEA		0.35			0.5
	MSS		0.35			0.5
Schedule of the carrying values of reporting units before and after the goodwill impairment expense	'
		September 30, 2012
		EMEA			MSS
	Carrying value before impairment	$	345.5		$	$
						347.8
	Goodwill impairment		(155.0	)		(181.0	)
	Carrying value after impairment	$	190.5		$	166.8
Schedule of changes in the carrying value of goodwill by reportable segment	'
		Fiscal Year 2014
		September 30,			Post-			Foreign			Acquired		September 30,
		2013			Acquisition			Exchange					2014
					Adjustments			Impact
		(in millions)
	Professional Technical Services	$	1,645.00		$	5		$	(31.3	)	$	151.8	$	1,770.50
	Management Support Services		166.8			—			—			—		166.8
	Total	$	1,811.80		$	5		$	(31.3	)	$	151.8	$	1,937.30
		Fiscal Year 2013
		September 30,			Post-			Foreign			Acquired		September 30,
		2012			Acquisition			Exchange					2013
					Adjustments			Impact
		(in millions)
	Professional Technical Services	$	1,608.60		$	—		$	(36.2	)	$	72.6	$	1,645.00
	Management Support Services		166.8			—			—			—		166.8
	Total	$	1,775.40		$	—		$	(36.2	)	$	72.6	$	1,811.80
Schedule of finite-lived intangible assets by major class	'
		September 30, 2014		September 30, 2013
		Gross		Accumulated		Intangible		Gross		Accumulated				Intangible		Amortization
		Amount		Amortization		Assets, Net		Amount		Amortization				Assets, Net		Period
																(years)
		(in millions)
	Backlog	$	110		$	(97.4	)		12.6		$	94.9	$	(89.4	)	$	5.5	1 - 5
	Customer relationships		161.6			(85.4	)		76.2			147.1		(69.5	)		77.6	10
	Trademark / tradename		9.3			(7.9	)		1.4			7.8		(7.8	)		—	2
	Total	$	280.9		$	(190.7	)	$	90.2		$	249.8	$	(166.7	)	$	83.1
Schedule of estimated future amortization expense of intangible assets	'
	Fiscal Year	(in millions)
	2015	$	26.5
	2016		17.5
	2017		13.2
	2018		9.9
	2019		9.0
	Thereafter		14.1
	Total	$	90.2

Accounts_ReceivableNet_Tables

Accounts Receivable-Net (Tables)	12 Months Ended
	Sep. 30, 2014
Accounts Receivable-Net	'
Schedule of net accounts receivable	'
		Fiscal Year Ended
		September 30,			September 30,
		2014			2013
		(in millions)
	Billed	$	1,248.40		$	1,177.60
	Unbilled		1,214.80			1,076.80
	Contract retentions		263.9			174.3
	Total accounts receivable—gross		2,727.10			2,428.70
	Allowance for doubtful accounts		(72.1	)		(86.4	)
	Total accounts receivable—net	$	2,655.00		$	2,342.30

Property_and_Equipment_Tables

Property and Equipment (Tables)	12 Months Ended
	Sep. 30, 2014
Property and Equipment.	'
Schedule of property and equipment, at cost	'
		Fiscal Year Ended
		September 30,			September 30,			Useful Lives
		2014			2013			(years)
		(in millions)
	Building and land	$	11.5		$	4.4		27
	Leasehold improvements		299.7			289.9		2 - 12
	Computer systems and equipment		302.6			257		3 - 10
	Furniture and fixtures		101.5			106.4		5 - 10
	Automobiles		6.8			5.4		3 - 10
	Total		722.1			663.1
	Accumulated depreciation and amortization		(440.1	)		(392.4	)
	Property and equipment, net	$	282		$	270.7

Joint_Ventures_and_Variable_In1

Joint Ventures and Variable Interest Entities (Tables)	12 Months Ended
	Sep. 30, 2014
Joint Ventures and Variable Interest Entities	'
Summary of unaudited financial information of the consolidated joint ventures	'
		September 30,		September 30,
		2014		2013
		(in millions)
	Current assets	$	314.1	$	185.7
	Non-current assets		106.2		—
	Total assets	$	420.3	$	185.7
	Current liabilities	$	229.1	$	38.9
	Non-current liabilities		—		—
	Total liabilities		229.1		38.9
	Total AECOM equity		116.6		106.8
	Noncontrolling interests		74.6		40.0
	Total owners' equity		191.2		146.8
	Total liabilities and owners' equity	$	420.3	$	185.7
Summary of unaudited financial information of the unconsolidated joint ventures	'
		September 30,		September 30,
		2014		2013
		(in millions)
	Current assets	$	539.6	$	525.5
	Non-current assets		273.7		98.7
	Total assets	$	813.3	$	624.2
	Current liabilities	$	397.9	$	384.1
	Non-current liabilities		91.0		17.5
	Total liabilities		488.9		401.6
	Joint venturers' equity		324.4		222.6
	Total liabilities and joint venturers' equity	$	813.3	$	624.2
	AECOM's investment in joint ventures	$	142.9	$	106.4
Summary of AECOM's equity in earnings of unconsolidated joint ventures	'
		Fiscal Year Ended
		September 30,		September 30,		September 30,
		2014		2013		2012
		(in millions)
	Pass through joint ventures	$	10.2	$	6.4	$	5.2
	Other joint ventures		47.7		17.9		43.4
	Total	$	57.9	$	24.3	$	48.6

Pension_Plans_Tables

Pension Plans (Tables)	12 Months Ended
	Sep. 30, 2014
Pension Plans	'
Reconciliations of the changes in the U.S. and international plans' benefit obligations	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Change in benefit obligation:
	Benefit obligation at beginning of year	$	180.3		$	622.1		$	192.9		$	574		$	171		$	504.3
	Service cost		—			0.7			—			0.9			—			1.1
	Participant contributions		0.4			0.2			0.4			0.3			0.6			0.3
	Interest cost		7.8			27.9			6.6			23.8			7.7			25.6
	Benefits paid		(12.8	)		(23.3	)		(11.0	)		(18.8	)		(10.0	)		(25.7	)
	Actuarial (gain) loss		23.2			62.3			(8.6	)		49			23.6			50.3
	Plan settlements		—			(2.0	)		—			(5.7	)		—			(2.4	)
	Net transfer in/(out)/acquisitions		18.1			—			—			—			—			—
	Foreign currency translation (gain) loss		—			(11.3	)		—			(1.4	)		—			20.5
	Benefit obligation at end of year	$	217		$	676.6		$	180.3		$	622.1		$	192.9		$	574
Reconciliations of the changes in the fair value of assets	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		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	$	119.8		$	489.9		$	112.3		$	462.4		$	91.5		$	417.3
	Actual return on plan assets		14.2			60.4			11.3			37.4			17			39
	Employer contributions		4.9			16.4			6.8			16.2			13.2			17.2
	Participant contributions		0.4			0.2			0.4			0.3			0.6			0.3
	Benefits paid		(12.8	)		(23.3	)		(11.0	)		(18.8	)		(10.0	)		(25.7	)
	Plan settlements		—			(2.0	)		—			(5.7	)		—			(2.4	)
	Net transfer in/(out)/acquisitions		13.2			—			—			—			—			—
	Foreign currency translation (loss) gain		—			(9.0	)		—			(1.9	)		—			16.7
	Fair value of plan assets at end of year	$	139.7		$	532.6		$	119.8		$	489.9		$	112.3		$	462.4
Reconciliations of the funded status	'
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Reconciliation of funded status:
	Funded status at end of year	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
	Contribution made after measurement date		N/A			N/A			N/A			N/A			N/A			N/A
	Net amount recognized at end of year	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
Amounts recognized in the consolidated balance sheets	'
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		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	$	—		$	1.1		$	—		$	0.6		$	—		$	—
	Accrued expenses and other current liabilities		(1.7	)		—			(1.4	)		—			(1.7	)		—
	Other long-term liabilities		(75.6	)		(145.1	)		(59.1	)		(132.8	)		(78.9	)		(111.6	)
	Net amount recognized in the balance sheet	$	(77.3	)	$	(144.0	)	$	(60.5	)	$	(132.2	)	$	(80.6	)	$	(111.6	)
Reconciliation of amounts in the consolidated statements of stockholders' equity	'
		Fiscal Year Ended
		September 30, 2014						September 30, 2013						September 30, 2012
		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 credit	$	—		$	5.8		$	—		$	6		$	—		$	6.2
	Net (loss)		(113.0	)		(190.1	)		(99.4	)		(170.7	)		(115.1	)		(143.2	)
	Total recognized in accumulated other comprehensive (loss)	$	(113.0	)	$	(184.3	)	$	(99.4	)	$	(164.7	)	$	(115.1	)	$	(137.0	)
Components of net periodic cost for the Company's pension plans	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Components of net periodic (benefit) cost:
	Service costs	$	—		$	0.7		$	—		$	1		$	—		$	1.1
	Interest cost on projected benefit obligation		7.8			27.9			6.6			23.8			7.7			25.6
	Expected return on plan assets		(8.6	)		(26.1	)		(8.5	)		(22.7	)		(8.4	)		(25.3	)
	Amortization of prior service costs		—			(0.2	)		—			(0.2	)		—			(0.2	)
	Amortization of net loss		4			4.9			4.3			4			3.1			2.3
	Settlement loss recognized		—			0.4			—			2.6			—			0.5
	Net periodic (benefit) cost	$	3.2		$	7.6		$	2.4		$	8.5		$	2.4		$	4
Amounts included in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost during the next fiscal year	'
	Amounts included in accumulated other comprehensive loss as of September 30, 2014 that are expected to be recognized as components of net periodic benefit cost during fiscal 2015 are (in millions):
		U.S.			Int'l
	Amortization of prior service cost	$	—		$	0.2
	Amortization of net actuarial losses		(4.3	)		(6.2	)
	Total	$	(4.3	)	$	(6.0	)
Additional year-end information for pension plans with accumulated benefit obligations in excess of plan assets	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
		(in millions)
	Projected benefit obligation	$	217.0		$	658.5		$	180.3		$	601.7		$	192.9		$	574.0
	Accumulated benefit obligation		217.0			656.3			180.3			599.8			192.9			570.6
	Fair value of plan assets		139.7			513.4			119.8			469.0			112.3			462.4
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
	2015	$	12.2		$	26.5
	2016		14.9			21.9
	2017		13.4			26.3
	2018		12.9			29.1
	2019		13.4			25.8
	2020 - 2024		68.3			153.3
	Total	$	135.1		$	282.9
Schedule of underlying assumptions for the pension plans	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
	Weighted-average assumptions to determine benefit obligation:
	Discount rate		4.00	%		3.94	%		4.40	%		4.44	%		3.50	%		4.39	%
	Salary increase rate		N/A			2.38	%		N/A			2.58	%		N/A			2.36	%
	Weighted-average assumptions to determine net periodic benefit cost:
	Discount rate		4.40	%		4.44	%		3.50	%		4.39	%		4.65	%		5.12	%
	Salary increase rate		N/A			2.58	%		N/A			2.36	%		N/A			2.65	%
	Expected long-term rate of return on plan assets		7.50	%		5.40	%		7.50	%		5.11	%		7.50	%		5.65	%
Summary of the Company's target allocation and pension plan asset allocation, both U.S. and international	'
								Percentage of Plan Assets
		Target						as of September 30,
		Allocations						2014						2013
		U.S.			Int'l			U.S.			Int'l			U.S.			Int'l
	Asset Category
	Equities		45	%		1	%		58	%		28	%		49	%		28	%
	Debt		42			47			31			33			34			37
	Cash		3			1			1			3			1			4
	Property and other		10			51			10			36			16			31
	Total		100	%		100	%		100	%		100	%		100	%		100	%
Fair values of the Company's post-retirement benefit plan assets by major asset categories	'
					Fair Value Measurement as of
					September 30, 2014
		Total			Quoted			Significant			Significant
		Carrying			Prices in			Other			Unobservable
		Value as of			Active			Observable			Inputs
		September 30,			Markets			Inputs			(Level 3)
		2014			(Level 1)			(Level 2)
		(in millions)
	Cash and cash equivalents	$	7.9		$	3.4		$	4.5		$	—
	Investment funds
	Diversified funds		159.3			—			159.3			—
	Equity funds		220.3			—			220.3			—
	Fixed income funds		219.3			—			219.3			—
	Hedge funds		27.9			—			14.2			13.7
	Assets held by insurance company		37.6			—			37.6			—
	Total	$	672.3		$	3.4		$	655.2		$	13.7
					Fair Value Measurement as of September 30, 2013
		Total			Quoted			Significant			Significant
		Carrying			Prices in			Other			Unobservable
		Value as of			Active			Observable			Inputs
		September 30,			Markets			Inputs			(Level 3)
		2013			(Level 1)			(Level 2)
		(in millions)
	Cash and cash equivalents	$	11.0		$	11.0		$	—		$	—
	Investment funds
	Diversified funds		108.6			—			108.6			—
	Equity funds		192.4			—			192.4			—
	Fixed income funds		220.6			—			220.6			—
	Hedge funds		25.0			—			12.4			12.6
	Assets held by insurance company		46.1			—			46.1			—
	Real estate		6.0			—			6.0			—
	Total	$	609.7		$	11.0		$	586.1		$	12.6
Changes in the fair value of the Company's post-retirement plan Level 3 assets	'
		September 30,			Actual return			Actual return			Purchases,			Transfer			Change			September 30,
		2013			on plan assets,			on plan assets,			sales and			into /			due to			2014
		Beginning			relating to			relating to			settlements			(out of)			exchange			Ending
		balance			assets still held			assets sold						Level 3			rate			balance
					at reporting			during the									changes
					date			period
		(in millions)
	Investment funds
	Hedge funds	$	12.6		$	1.1		$	—		$	—		$	—		$	—		$	13.7
	Total	$	12.6		$	1.1		$	—		$	—		$	—		$	—		$	13.7
		September 30,			Actual return			Actual return			Purchases,			Transfer			Change			September 30,
		2012			on plan assets,			on plan assets,			sales			into /			due to			2013
		Beginning			relating to			relating to			and			(out of)			exchange			Ending
		balance			assets still held			assets sold			settlements			Level 3			rate			balance
					at reporting			during the									changes
					date			period
		(in millions)
	Investment funds
	Hedge funds	$	10.6		$	2.0		$	—		$	—		$	—		$	—		$	12.6
	Total	$	10.6		$	2.0		$	—		$	—		$	—		$	—		$	12.6

Debt_Tables

Debt (Tables)	12 Months Ended
	Sep. 30, 2014
Debt	'
Schedule of debt	'
		September 30,			September 30,
		2014			2013
		(in millions)
	Unsecured term credit agreement	$	712.5		$	750
	Unsecured senior notes		263.9			260.2
	Unsecured revolving credit facility		—			114.7
	Other debt		27.6			48.4
	Total debt		1,004.00			1,173.30
	Less: Current portion of debt and short-term borrowings		(64.4	)		(84.3	)
	Long-term debt, less current portion	$	939.6		$	1,089.00
Schedule of maturities of debt	'
	The following table presents, in millions, scheduled maturities of our debt as of September 30, 2014:
	Fiscal Year
	2015	$	64.4
	2016		38.0
	2017		37.7
	2018		600.0
	2019		—
	Thereafter		263.9
	Total	$	1,004.0

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	12 Months Ended
	Sep. 30, 2014
Derivative Financial Instruments	'
Notional principle, fixed rates and related expiration dates of outstanding interest rate swap agreements	'
			September 30, 2014
			Notional Amount			Fixed			Expiration
			(in millions)			Rate			Date
			$	300.0			1.63	%	Jun-18
				250.0			0.95	%	Sep-15
				200.0			0.68	%	Dec-14
			September 30, 2013
			Notional Amount			Fixed			Expiration
			(in millions)			Rate			Date
			$	250.0			0.95	%	Sep-15
				200.0			0.68	%	Dec-14
				150.0			0.55	%	Dec-13
Fair values of outstanding derivative instruments	'
	The fair values of our outstanding derivative instruments were as follows (in millions):
					Fair Value of
					Derivative
					Instruments
					as of
			Balance Sheet Location		Sep 30,			Sep 30,
					2014			2013
	Derivative assets
	Derivatives designated as hedging instruments:
	Foreign currency options		Prepaid expenses and other current assets		$	—		$	0.1
	Interest rate swap agreements		Other non-current asset			1.7			—
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		Prepaid expenses and other current assets			3.1			1.6
	Total				$	4.8		$	1.7
	Derivative liabilities
	Derivatives designated as hedging instruments:
	Interest rate swap agreements		Accrued expenses and other current liabilities		$	4.8		$	2.6
	Interest rate swap agreements		Other long-term liabilities			—			1.1
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		Accrued expenses and other current liabilities			3.7			1.5
	Total				$	8.5		$	5.2
Summary of effect of derivative instruments in cash flow hedging relationships on income and other comprehensive income	'
	The effect of derivative instruments in cash flow hedging relationships on income and other comprehensive income is summarized below (in millions):
			Increase in Losses
			Recognized in Accumulated
			Other Comprehensive Loss
			on Derivatives Before Tax
			Effect (Effective Portion)
			Year Ended September 30,
			2014			2013			2012
	Derivatives in cash flow hedging relationship:
	Interest rate swap agreements		$	(2.4	)	$	(0.5	)	$	(8.4	)
					Losses Reclassified from
					Accumulated Other
					Comprehensive Loss into
					Income (Effective Portion)
					Year Ended September 30,
			Location		2014			2013			2012
	Derivatives in cash flow hedging relationship:
	Interest rate swap agreements		Interest expense		$	(2.9	)	$	(3.1	)	$	(2.2	)
	Foreign currency options		Cost of revenue			(0.1	)		—			—
					Losses Recognized in
					Income on Derivatives
					(Amount Excluded from
					Effectiveness Testing and
					Ineffective Portion)(1)
					Year Ended September 30,
			Location		2014			2013			2012
	Derivatives in cash flow hedging relationship:
	Foreign currency options		Cost of revenue		$	—		$	(0.1	)	$	(0.1	)
	-1	Losses related to the ineffective portion of the hedges were not material in all periods presented.
Summary of effect of derivative instruments not designated as hedging instruments on income	'
	The effect of derivative instruments not designated as hedging instruments on income is summarized below (in millions):
					Gains / (Losses) Recognized
					in Income on Derivatives
					(Amount Excluded from
					Effectiveness Testing and
					Ineffective Portion)(1)
					Year Ended September 30,
			Location		2014			2013			2012
	Derivatives not designated as hedging instruments:
	Foreign currency forward contracts		General and administrative expenses		$	(0.1	)	$	(4.7	)	$	4.2
	Foreign currency forward contracts		Cost of revenue			—			—			0.1
	Option contracts		Cost of revenue			—			(0.3	)		(0.1	)
					$	(0.1	)	$	(5.0	)	$	4.2
	-1	Losses related to the ineffective portion of the hedges were not material in all periods presented.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Sep. 30, 2014
Fair Value Measurements	'
Non-pension financial assets and liabilities measured at fair value on a recurring basis	'
	The following table summarizes the Company's non-pension financial assets and liabilities measured at fair value on a recurring basis (at least annually) in millions:
		September 30,		Quoted Prices in
		2014		Active Markets for
				Similar Assets
				(Level 2)
	Interest rate swap agreements	$	1.7	$	1.7
	Foreign currency forward contracts		3.1		3.1
	Total assets	$	4.8	$	4.8
	Interest rate swap agreements	$	4.8	$	4.8
	Foreign currency forward contracts		3.7		3.7
	Total liabilities	$	8.5	$	8.5
		September 30,		Quoted Prices in
		2013		Active Markets for
				Similar Assets
				(Level 2)
	Foreign currency options	$	0.1	$	0.1
	Foreign currency forward contracts		1.6		1.6
	Total assets	$	1.7	$	1.7
	Interest rate swap agreements	$	3.7	$	3.7
	Foreign currency forward contracts		1.5		1.5
	Total liabilities	$	5.2	$	5.2

Leases_Tables

Leases (Tables)	12 Months Ended
	Sep. 30, 2014
Leases	'
Schedule of amounts payable under non-cancelable operating lease commitments	'
	Year Ending September 30,
	2015	$	181.4
	2016		154.8
	2017		126.4
	2018		102.6
	2019		86.1
	Thereafter		234.7
	Total	$	886.0

Other_Financial_Information_Ta

Other Financial Information (Tables)	12 Months Ended
	Sep. 30, 2014
Other Financial Information	'
Schedule of accrued expenses and other current liabilities	'
		Fiscal Year Ended
		September 30,		September 30,
		2014		2013
		(in millions)
	Accrued salaries and benefits	$	400.6	$	410.6
	Accrued contract costs		446.4		404.2
	Other accrued expenses		117.6		100.5
		$	964.6	$	915.3
Schedule of other long-term liabilities	'
		Fiscal Year Ended
		September 30,		September 30,
		2014		2013
		(in millions)
	Pension liabilities (Note 8)	$	221.3	$	192.7
	Reserve for uncertain tax positions (Note 18)		52.6		60.2
	Other		181.7		196.0
		$	455.6	$	448.9

Reclassifications_out_of_Accum

Reclassifications out of Accumulated Other Comprehensive Losses (Tables)	12 Months Ended
	Sep. 30, 2014
Reclassifications out of Accumulated Other Comprehensive Loss	'
Schedule of accumulated balances and reporting period activities related to reclassifications out of accumulated other comprehensive loss	'
	The accumulated balances and reporting period activities for the years ended September 30, 2014, 2013 and 2012 related to reclassifications out of accumulated other comprehensive loss are summarized as follows (in millions):
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2011		$	(136.5	)	$	(51.1	)	$	—		$	(187.6	)
	Other comprehensive income before reclassification			(44.7	)		53.8			(5.0	)		4.1
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			3			—			—			3
	Cash flow hedge losses, net of tax			—			—			1.3			1.3
	Balances at September 30, 2012		$	(178.2	)	$	2.7		$	(3.7	)	$	(179.2	)
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2012		$	(178.2	)	$	2.7		$	(3.7	)	$	(179.2	)
	Other comprehensive income before reclassification			(19.9	)		(69.1	)		(0.2	)		(89.2	)
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			5.3			—			—			5.3
	Cash flow hedge losses, net of tax			—			—			1.8			1.8
	Balances at September 30, 2013		$	(192.8	)	$	(66.4	)	$	(2.1	)	$	(261.3	)
			Pension			Foreign			Loss on			Accumulated
			Related			Currency			Derivative			Other
			Adjustments			Translation			Instruments			Comprehensive
						Adjustments						Loss
	Balances at September 30, 2013		$	(192.8	)	$	(66.4	)	$	(2.1	)	$	(261.3	)
	Other comprehensive income before reclassification			(30.3	)		(71.4	)		(1.4	)		(103.1	)
	Amounts reclassified from accumulated other comprehensive loss:
	Actuarial losses, net of tax			6.1			—			—			6.1
	Cash flow hedge losses, net of tax			—			—			1.7			1.7
	Balances at September 30, 2014		$	(217.0	)	$	(137.8	)	$	(1.8	)	$	(356.6	)
Schedule of amounts reclassified from accumulated other comprehensive loss	'
			Year Ended			Year Ended			Year Ended
			September 30,			September 30,			September 30,
			2014			2013			2012
	Cash flow hedges(1)		$	2.9		$	3		$	2.2
	Taxes			(1.2	)		(1.2	)		(0.9	)
	Cash flow hedges, net of tax		$	1.7		$	1.8		$	1.3
	Actuarial losses(2)		$	8.7		$	8		$	4.7
	Taxes			(2.6	)		(2.7	)		(1.7	)
	Actuarial losses, net of tax		$	6.1		$	5.3		$	3
	-1	This accumulated other comprehensive component is reclassified in Interest expense in our Consolidated Statements of Income. See Note 10, Derivative Financial Instruments, for more information.
	-2	This accumulated other comprehensive component is reclassified in Cost of revenue and General and administrative expenses in our Consolidated Statements of Income. See Note 8, Pension Benefit Obligations, for more information.

Stock_Plans_Tables

Stock Plans (Tables)	12 Months Ended
	Sep. 30, 2014
Stock Plans	'
Schedule of stock option activity	'
		Number of			Weighted
		Options			Average
		(in millions)			Exercise Price
	Balance, September 30, 2011		2.9		$	21.38
	Granted		—			—
	Exercised		(0.4	)		11.4
	Cancelled		—			26.23
	Balance, September 30, 2012		2.5			22.81
	Granted		—			—
	Exercised		(0.8	)		18.31
	Cancelled		(0.1	)		26.83
	Balance, September 30, 2013		1.6			24.73
	Granted		0.6			31.62
	Exercised		(0.5	)		23.64
	Cancelled		(0.1	)		26.87
	Balance, September 30, 2014		1.6			27.69
	Exercisable as of September 30, 2012		2.1		$	22.07
	Exercisable as of September 30, 2013		1.4			24.51
	Exercisable as of September 30, 2014		0.9			25.16
Summary of information concerning outstanding and exercisable options	'
		Options Outstanding									Options Exercisable
		Number			Weighted		Weighted		Aggregate		Number		Weighted		Weighted
		Outstanding			Average		Average		Intrinsic		Exercisable		Average		Average
		as of			Remaining		Exercise		Value		as of		Remaining		Exercise
		September 30,			Contractual		Price		(in millions)		September 30,		Contractual		Price
		2014			Life						2014		Life
		(in millions)									(in millions)
	Range of Exercise Prices
	$21.01 - $23.94		0.4			1.18	$	23.46	$	4.1		0.4		1.18	$	23.46
	24.45 -  28.67		0.5			2.06		26.24		3.6		0.5		2.06		26.24
	30.96 -  34.00		0.7			9.17		31.65		0.8		—		0.66		32.53
			1.6			4.69		27.69	$	8.5		0.9		1.65		25.16

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Sep. 30, 2014
Income Taxes	'
Schedule of income tax expense (benefit) on continuing operations	'
		Fiscal Year Ended
		September 30,			September 30,			September 30,
		2014			2013			2012
		(in millions)
	Current:
	Federal	$	5.3		$	30.3		$	29.3
	State		3.3			9.9			2.1
	Foreign		46.3			59.7			63.3
	Total current income tax expense		54.9			99.9			94.7
	Deferred:
	Federal		27.7			5.8			(19.2	)
	State		5.6			(10.6	)		0.6
	Foreign		(6.2	)		(2.5	)		(1.7	)
	Total deferred income tax expense (benefit)		27.1			(7.3	)		(20.3	)
	Total income tax expense	$	82		$	92.6		$	74.4
Major elements contributing to the difference between the U.S. federal statutory rate of 35.0% and the effective tax rate	'
		Fiscal Year Ended
		September 30,						September 30,						September 30,
		2014						2013						2012
		Amount			%			Amount			%			Amount			%
		(in millions)
	Tax at federal statutory rate	$	110.2			35	%	$	117.5			35	%	$	6.1			35	%
	State income tax, net of federal benefit		5			1.6			2.5			0.7			1.1			6.3
	U.S. income tax credits and incentives		(3.5	)		(1.1	)		(10.8	)		(3.2	)		(2.9	)		(16.6	)
	Foreign tax rate differential		(22.5	)		(7.2	)		(9.9	)		(2.9	)		(25.4	)		(145.1	)
	Foreign Research and Experimentation credits		(3.6	)		(1.1	)		(3.9	)		(1.1	)		(5.8	)		(33.3	)
	Goodwill impairment		—			—			—			—			101.1			578.3
	Change in uncertain tax positions		(4.5	)		(1.4	)		(7.3	)		(2.2	)		(4.1	)		(23.4	)
	Valuation allowance		6.3			2			1.6			0.5			0.5			2.7
	Domestic production activities deduction		(11.7	)		(3.7	)		(2.6	)		(0.8	)		(1.2	)		(6.8	)
	Nondeductible transaction costs		2.8			0.9			—			—			1.3			7.6
	Other items, net		3.5			1.1			5.5			1.6			3.7			21
	Total income tax expense	$	82			26.1	%	$	92.6			27.6	%	$	74.4			425.7	%
Schedule of deferred tax assets (liabilities)	'
		Fiscal Year Ended
		September 30,			September 30,
		2014			2013
		(in millions)
	Deferred tax assets:
	Compensation and benefit accruals not currently deductible	$	65.5		$	74.7
	Net operating loss carry forwards		69.3			58.1
	Self insurance reserves		48.8			54.7
	Research and Experimentation and other tax credits		34.2			38.3
	Pension liability		59.4			58.5
	Accrued liabilities		63.7			56.1
	Investments in joint ventures/non-controlled subsidiaries		20.7			13.9
	State taxes		1.5			0.9
	Other		4			4.2
	Total deferred tax assets		367.1			359.4
	Deferred tax liabilities:
	Unearned revenue		(122.9	)		(139.3	)
	Depreciation and amortization		(59.2	)		(20.1	)
	Acquired intangible assets		(14.8	)		(15.8	)
	Total deferred tax liabilities		(196.9	)		(175.2	)
	Valuation allowance		(27.1	)		(20.8	)
	Net deferred tax assets	$	143.1		$	163.4
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits	'
		Fiscal Year Ended
		September 30,			September 30,
		2014			2013
		(in millions)
	Balance at the beginning of the year	$	53.7		$	55.8
	Gross increase in prior years' tax positions		3.3			7.2
	Gross decrease in prior years' tax positions		(7.6	)		(5.6	)
	Decrease due to settlement with tax authorities		(2.0	)		(1.6	)
	Gross increase in current period's tax positions		2.2			3.8
	Lapse of statute of limitations		(2.1	)		(5.9	)
	Balance at the end of the year	$	47.5		$	53.7

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Sep. 30, 2014
Earnings Per Share	'
Reconciliation of the denominators for basic and diluted EPS	'
		Fiscal Year Ended
		September 30,		September 30,		September 30,
		2014		2013		2012
		(in millions)
	Denominator for basic earnings per share		97.2		100.6		111.9
	Potential common shares		1.5		1.3		—
	Denominator for diluted earnings per share		98.7		101.9		111.9

Reportable_Segments_Tables

Reportable Segments (Tables)	12 Months Ended
	Sep. 30, 2014
Reportable Segments and Geographic	'
Summarized financial information concerning the Company's reportable segments	'
	Reportable Segments:		Professional			Management			Corporate			Total
			Technical			Support
			Services			Services
			(in millions)
	Fiscal Year Ended September 30, 2014:
	Revenue		$	7,609.90		$	746.9		$	—		$	8,356.80
	Revenue, net of other direct costs(1)			4,462.70			392.9			—			4,855.60
	Gross profit			365.2			38			—			403.2
	Equity in earnings of joint ventures			41.4			16.5			—			57.9
	General and administrative expenses			—			—			(80.9	)		(80.9	)
	Acquisition and integration expenses			—			—			(27.3	)		(27.3	)
	Operating income (loss)			406.6			54.5			(108.2	)		352.9
	Segment assets			5,366.00			392.4			365			6,123.40
	Gross profit as a % of revenue			4.8	%		5.1	%					4.8	%
	Gross profit as a % of revenue, net of other direct costs(1)			8.2	%		9.7	%					8.3	%
	Fiscal Year Ended September 30, 2013:
	Revenue		$	7,242.90		$	910.6		$	—		$	8,153.50
	Revenue, net of other direct costs(1)			4,416.40			560.6			—			4,977.00
	Gross profit			416.9			33.1			—			450
	Equity in earnings of joint ventures			12.3			12			—			24.3
	General and administrative expenses			—			—			(97.3	)		(97.3	)
	Operating income (loss)			429.2			45.1			(97.3	)		377
	Segment assets			4,827.50			598			240.1			5,665.60
	Gross profit as a % of revenue			5.8	%		3.6	%					5.5	%
	Gross profit as a % of revenue, net of other direct costs(1)			9.4	%		5.9	%					9	%
	Fiscal Year Ended September 30, 2012:
	Revenue		$	7,276.90		$	941.3		$	—		$	8,218.20
	Revenue, net of other direct costs(1)			4,607.30			576.6			—			5,183.90
	Gross profit			423.8			(1.9	)		—			421.9
	Equity in earnings of joint ventures			16.8			31.8			—			48.6
	General and administrative expenses			—			—			(80.9	)		(80.9	)
	Goodwill impairment			(155.0	)		(181.0	)		—			(336.0	)
	Operating income (loss)			285.6			(151.1	)		(80.9	)		53.6
	Gross profit as a % of revenue			5.8			(0.2						5.1
					%			)%						%
	Gross profit as a % of revenue, net of other direct costs(1)			9.2	%		(0.3	)%					8.1	%
	-1	Non-GAAP measure.
Schedule of geographic information	'
			Fiscal Year Ended
			September 30, 2014						September 30, 2013						September 30, 2012
			Revenue			Long-Lived			Revenue			Long-Lived			Revenue		Long-Lived
						Assets						Assets					Assets
			(in millions)
	United States		$	4,933.7			1,603.7		$	4,829.6			1,477.3		$	4,756.0		1,496.8
	Asia Pacific			1,338.2			340.5			1,507.2			361.0			1,715.1		374.9
	Canada			561.1			146.7			712.0			168.4			708.8		189.2
	Europe			788.2			270.8			599.4			267.2			608.2		243.6
	Other foreign countries			735.6			209.5			505.3			116.6			430.1		85.8
	Total		$	8,356.8			2,571.2		$	8,153.5			2,390.5		$	8,218.2		2,390.3

Quarterly_Financial_Informatio1

Quarterly Financial Information-Unaudited (Tables)	12 Months Ended
	Sep. 30, 2014
Quarterly Financial Information-Unaudited	'
Schedule of unaudited quarterly data	'
	Fiscal Year 2014:	First			Second			Third			Fourth
		Quarter			Quarter			Quarter			Quarter
		(in millions, except per share data)
	Revenue	$	1,953.90		$	1,872.20		$	1,968.20		$	2,562.50
	Cost of revenue		1,875.70			1,784.80			1,859.70			2,433.40
	Gross profit		78.2			87.4			108.5			129.1
	Equity in earnings of joint ventures		36.1			7.4			6			8.4
	General and administrative expenses		(23.9	)		(26.4	)		(15.1	)		(15.5	)
	Acquisition and integration expenses		—			—			(7.8	)		(19.5	)
	Income from operations		90.4			68.4			91.6			102.5
	Other income (expenses)		—			(0.2	)		1			1.9
	Interest expense		(10.4	)		(10.5	)		(9.8	)		(10.1	)
	Income before income tax expense		80			57.7			82.8			94.3
	Income tax expense		23.5			15.2			13.7			29.6
	Net income		56.5			42.5			69.1			64.7
	Noncontrolling interest in income of consolidated subsidiaries, net of tax		(0.1	)		(2.3	)		0.1			(0.6	)
	Net income attributable to AECOM	$	56.4		$	40.2		$	69.2		$	64.1
	Net income attributable to AECOM per share:
	Basic	$	0.59		$	0.41		$	0.71		$	0.65
	Diluted	$	0.58		$	0.41		$	0.7		$	0.64
	Weighted average common shares outstanding:
	Basic		96.3			97			97.5			98.1
	Diluted		97.6			98.3			99			99.7
	Fiscal Year 2013:	First			Second			Third			Fourth
		Quarter			Quarter			Quarter			Quarter
		(in millions, except per share data)
	Revenue	$	2,017.30		$	1,989.60		$	2,067.50		$	2,079.10
	Cost of revenue		1,939.20			1,889.70			1,935.70			1,938.90
	Gross profit		78.1			99.9			131.8			140.2
	Equity in earnings of joint ventures		5.9			7.9			4.1			6.4
	General and administrative expenses		(22.1	)		(27.3	)		(24.0	)		(23.9	)
	Income from operations		61.9			80.5			111.9			122.7
	Other income		0.7			0.1			1.2			1.5
	Interest expense		(10.9	)		(11.9	)		(11.7	)		(10.2	)
	Income before income tax expense		51.7			68.7			101.4			114
	Income tax expense		12.7			14			30.1			35.8
	Net income		39			54.7			71.3			78.2
	Noncontrolling interest in income of consolidated subsidiaries, net of tax		(0.9	)		(0.9	)		(0.5	)		(1.7	)
	Net income attributable to AECOM	$	38.1		$	53.8		$	70.8		$	76.5
	Net income attributable to AECOM per share:
	Basic	$	0.36		$	0.54		$	0.71		$	0.78
	Diluted	$	0.36		$	0.53		$	0.7		$	0.77
	Weighted average common shares outstanding:
	Basic		104.8			100.4			99.3			98
	Diluted		105.5			101.8			100.8			99.7

Significant_Accounting_Policie2

Significant Accounting Policies (Details) (USD $)	12 Months Ended
In Billions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
	item
Fiscal Year	'	'	'	'
Fiscal year period	'	'364 days	'364 days	'364 days
Revenue Recognition	'	'	'	'
Other direct costs	$3.50	$3.20	$3	'
Cost-Plus Contracts	'	'	'	'
Number of major types of cost-plus contracts the Company enters into	2	'	'	'
Fixed Price Contracts	'	'	'	'
Number of types of fixed price contracts	2	'	'	'
Pension Plans	'	'	'	'
Amortization period of the difference between actual return and expected return	'5 years	'	'	'
Specified percentage to be exceeded for amortization of cumulative, net unrecognized gains or losses (as a percent)	10.00%	'	'	'

Significant_Accounting_Policie3

Significant Accounting Policies (Details 2)	12 Months Ended
	Sep. 30, 2014
Minimum [Member]	'
Length of fiscal year	'364 days
Property and Equipment	'
Estimated useful lives for equipment furniture and fixtures	'3 years
Maximum	'
Length of fiscal year	'371 days
Property and Equipment	'
Estimated useful lives for equipment furniture and fixtures	'10 years

Stock_Repurchase_Program_Detai

Stock Repurchase Program (Details) (USD $)	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014
Stock Repurchase Program	'
Authorized amount of stock repurchase	$1,000,000,000
Shares repurchased and retired under the agreement	27.4
Total cost of shares repurchased under the agreement	$660,100,000
Average price per share of stock repurchased under the agreement (in dollars per share)	$24.10

Business_Acquisitions_Goodwill2

Business Acquisitions, Goodwill and Intangible Assets (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
	item	item	item
Business Acquisitions, Goodwill, and Intangible Assets	'	'	'
Number of business acquisitions	2	2	1
Aggregate value of all consideration for acquisitions consummated	$88.50	$82	$15.40
Estimated fair values of the assets acquired and liabilities assumed, as of the acquisition dates, from acquisitions	'	'	'
Cash acquired	17.1	20.1	1.9
Other current assets	256.2	41.5	7.8
Goodwill	72.7	72.6	10.5
Intangible assets	11.9	9.4	1.5
Other non-current assets	16.5	8.6	3.3
Current liabilities	-274.1	-54.9	-8.8
Noncurrent liabilities	-11.8	-15.3	-0.8
Net assets acquired	$88.50	$82	$15.40

Business_Acquisitions_Goodwill3

Business Acquisitions, Goodwill and Intangible Assets (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Consideration for acquisitions	'	'	'
Consideration paid in cash	$70.20	$62.10	$14.50
Senior notes assumed in acquisition as part of consideration	18.3	5.6	'
Equity issued	'	14.3	0.9
Total consideration	88.5	82	15.4
Maximum period to determine final value of identifiable intangible assets	'12 months	'	'
Acquired intangible assets	11.9	9.4	1.5
Contractual Rights [Member]	'	'	'
Consideration for acquisitions	'	'	'
Acquired intangible assets	5.8	4.2	0.7
Customer Relationships [Member]	'	'	'
Consideration for acquisitions	'	'	'
Acquired intangible assets	4.6	5.2	0.8
Trademarks and Trade Names [Member]	'	'	'
Consideration for acquisitions	'	'	'
Acquired intangible assets	$1.50	'	'

Business_Acquisitions_Goodwill4

Business Acquisitions, Goodwill and Intangible Assets (Details 3) (USD $)

12 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2012

Sep. 30, 2011

Sep. 30, 2014

Sep. 30, 2013

item

EMEA [Member]

EMEA [Member]

Unconsolidated Joint Ventures [Member]

Professional Technical Services [Member]

Professional Technical Services [Member]

Professional Technical Services [Member]

Management Support Services [Member]

Management Support Services [Member]

Management Support Services [Member]

Management Support Services [Member]

Goodwill

'

'

'

'

'

'

'

'

'

'

'

'

'

Market multiple of revenue

'

'

'

0.35

0.5

'

'

'

'

0.35

0.5

'

'

Carrying value before impairment

'

'

'

$345,500,000

'

'

'

'

'

$347,800,000

'

'

'

Goodwill impairment

'

'

-336,000,000

-155,000,000

'

'

'

'

-155,000,000

-181,000,000

'

'

'

Carrying value after impairment

'

'

'

190,500,000

'

'

'

'

'

166,800,000

'

'

'

Goodwill Impairment, net of tax

'

'

317,200,000

'

'

'

'

'

'

'

'

'

'

Changes in the carrying value of goodwill by reporting segment

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill at the beginning of the period

1,811,754,000

'

1,775,400,000

'

'

'

1,645,000,000

'

1,608,600,000

166,800,000

'

166,800,000

166,800,000

Post-Acquisition Adjustments

5,000,000

'

'

'

'

'

5,000,000

'

'

'

'

'

'

Foreign Exchange Impact

-31,300,000

-36,200,000

'

'

'

'

-31,300,000

-36,200,000

'

'

'

'

'

Acquired

151,800,000

72,600,000

'

'

'

79,100,000

151,800,000

72,600,000

'

'

'

'

'

Goodwill impairment

'

'

-336,000,000

-155,000,000

'

'

'

'

-155,000,000

-181,000,000

'

'

'

Goodwill at the end of the period

$1,937,338,000

$1,811,754,000

'

'

'

'

$1,770,500,000

$1,645,000,000

'

'

$166,800,000

$166,800,000

$166,800,000

Number of reporting units

'

'

2

'

'

'

'

'

'

'

'

'

'

Business_Acquisitions_Goodwill5

Business Acquisitions, Goodwill and Intangible Assets (Details 4) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
2015	$26,500,000	'
2016	17,500,000	'
2017	13,200,000	'
2018	9,900,000	'
2019	9,000,000	'
Thereafter	14,100,000	'
Intangible Assets, Net	90,238,000	83,149,000
Gross Amount	280,900,000	249,800,000
Accumulated Amortization	-190,700,000	-166,700,000
Intangible Assets, Net	90,238,000	83,149,000
Amortization expense	24,000,000	21,200,000
Contractual Rights [Member]	'	'
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
Intangible Assets, Net	12,600,000	5,500,000
Gross Amount	110,000,000	94,900,000
Accumulated Amortization	-97,400,000	-89,400,000
Intangible Assets, Net	12,600,000	5,500,000
Contractual Rights [Member] | Minimum [Member]	'	'
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
Amortization Period	'1 year	'
Contractual Rights [Member] | Maximum	'	'
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
Amortization Period	'5 years	'
Customer Relationships [Member]	'	'
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
Intangible Assets, Net	76,200,000	77,600,000
Gross Amount	161,600,000	147,100,000
Accumulated Amortization	-85,400,000	-69,500,000
Intangible Assets, Net	76,200,000	77,600,000
Amortization Period	'10 years	'
Trademarks and Trade Names [Member]	'	'
Estimated amortization expense of intangible assets for the remainder of fiscal 2013 and for the succeeding years	'	'
Intangible Assets, Net	1,400,000	'
Gross Amount	9,300,000	7,800,000
Accumulated Amortization	-7,900,000	-7,800,000
Intangible Assets, Net	$1,400,000	'
Amortization Period	'2 years	'

Accounts_ReceivableNet_Details

Accounts Receivable-Net (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Accounts Receivable-Net	'	'
Billed	$1,248,400,000	$1,177,600,000
Unbilled	1,214,800,000	1,076,800,000
Contract retentions	263,900,000	174,300,000
Total accounts receivable-gross	2,727,100,000	2,428,700,000
Allowance for doubtful accounts	-72,100,000	-86,400,000
Total accounts receivable -net	2,654,976,000	2,342,262,000
Period in which unbilled receivables are expected to be billed and collected	'12 months	'12 months
Sale of trade receivables, outstanding	$111,900,000	$100,200,000

Property_and_Equipment_Details

Property and Equipment (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Property and equipment	'	'	'
Property and equipment, gross	$722,100,000	$663,100,000	'
Accumulated depreciation and amortization	-440,100,000	-392,400,000	'
Property and equipment, net	281,979,000	270,672,000	'
Depreciation expense	69,100,000	70,700,000	77,100,000
Amortization of capitalized software costs	7,300,000	6,400,000	6,200,000
Unamortized capitalized software costs	39,900,000	29,600,000	24,100,000
Minimum [Member]	'	'	'
Property and equipment	'	'	'
Useful Lives	'3 years	'	'
Maximum	'	'	'
Property and equipment	'	'	'
Useful Lives	'10 years	'	'
Land, Buildings and Improvements [Member]	'	'	'
Property and equipment	'	'	'
Property and equipment, gross	11,500,000	4,400,000	'
Useful Lives	'27 years	'	'
Leasehold Improvements [Member]	'	'	'
Property and equipment	'	'	'
Property and equipment, gross	299,700,000	289,900,000	'
Leasehold Improvements [Member] | Minimum [Member]	'	'	'
Property and equipment	'	'	'
Useful Lives	'2 years	'	'
Leasehold Improvements [Member] | Maximum	'	'	'
Property and equipment	'	'	'
Useful Lives	'12 years	'	'
Computer Equipment [Member]	'	'	'
Property and equipment	'	'	'
Property and equipment, gross	302,600,000	257,000,000	'
Computer Equipment [Member] | Minimum [Member]	'	'	'
Property and equipment	'	'	'
Useful Lives	'3 years	'	'
Computer Equipment [Member] | Maximum	'	'	'
Property and equipment	'	'	'
Useful Lives	'10 years	'	'
Furniture and Fixtures [Member]	'	'	'
Property and equipment	'	'	'
Property and equipment, gross	101,500,000	106,400,000	'
Furniture and Fixtures [Member] | Minimum [Member]	'	'	'
Property and equipment	'	'	'
Useful Lives	'5 years	'	'
Furniture and Fixtures [Member] | Maximum	'	'	'
Property and equipment	'	'	'
Useful Lives	'10 years	'	'
Automobiles [Member]	'	'	'
Property and equipment	'	'	'
Property and equipment, gross	$6,800,000	$5,400,000	'
Automobiles [Member] | Minimum [Member]	'	'	'
Property and equipment	'	'	'
Useful Lives	'3 years	'	'
Automobiles [Member] | Maximum	'	'	'
Property and equipment	'	'	'
Useful Lives	'10 years	'	'

Joint_Ventures_and_Variable_In2

Joint Ventures and Variable Interest Entities (Details) (USD $)

3 Months Ended

12 Months Ended

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2011

item

item

Financial information

'

'

'

'

'

'

'

'

'

'

'

'

Number of employees in some joint ventures

0

'

'

'

'

'

'

'

0

'

'

'

Current assets

$3,434,113,000

'

'

'

$3,131,602,000

'

'

'

$3,434,113,000

$3,131,602,000

'

'

TOTAL ASSETS

6,123,377,000

'

'

'

5,665,623,000

'

'

'

6,123,377,000

5,665,623,000

'

'

Current liabilities

2,455,769,000

'

'

'

2,053,549,000

'

'

'

2,455,769,000

2,053,549,000

'

'

TOTAL LIABILITIES

3,850,897,000

'

'

'

3,591,529,000

'

'

'

3,850,897,000

3,591,529,000

'

'

Total AECOM equity

2,186,517,000

'

'

'

2,021,443,000

'

'

'

2,186,517,000

2,021,443,000

'

'

Noncontrolling interests

85,963,000

'

'

'

52,651,000

'

'

'

85,963,000

52,651,000

'

'

TOTAL STOCKHOLDERS' EQUITY

2,272,480,000

'

'

'

2,074,094,000

'

'

'

2,272,480,000

2,074,094,000

2,224,488,000

2,395,137,000

TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY

6,123,377,000

'

'

'

5,665,623,000

'

'

'

6,123,377,000

5,665,623,000

'

'

AECOM's investment in joint ventures

142,901,000

'

'

'

106,422,000

'

'

'

142,901,000

106,422,000

'

'

Joint ventures summarized financial information

'

'

'

'

'

'

'

'

'

'

'

'

Total revenue

2,562,500,000

1,968,200,000

1,872,200,000

1,953,900,000

2,079,100,000

2,067,500,000

1,989,600,000

2,017,300,000

8,356,783,000

8,153,495,000

8,218,180,000

'

Total operating income

102,500,000

91,600,000

68,400,000

90,400,000

122,700,000

111,900,000

80,500,000

61,900,000

352,882,000

376,989,000

53,606,000

'

Summary of AECOM's equity in earnings of unconsolidated joint ventures:

'

'

'

'

'

'

'

'

'

'

'

'

Total

8,400,000

6,000,000

7,400,000

36,100,000

6,400,000

4,100,000

7,900,000

5,900,000

57,924,000

24,319,000

48,650,000

'

Minimum [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Financial information

'

'

'

'

'

'

'

'

'

'

'

'

Number of partners required to form joint ventures

2

'

'

'

'

'

'

'

2

'

'

'

Consolidated Joint Ventures [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Financial information

'

'

'

'

'

'

'

'

'

'

'

'

Current assets

314,100,000

'

'

'

185,700,000

'

'

'

314,100,000

185,700,000

'

'

Non-current assets

106,200,000

'

'

'

'

'

'

'

106,200,000

'

'

'

TOTAL ASSETS

420,300,000

'

'

'

185,700,000

'

'

'

420,300,000

185,700,000

'

'

Current liabilities

229,100,000

'

'

'

38,900,000

'

'

'

229,100,000

38,900,000

'

'

TOTAL LIABILITIES

229,100,000

'

'

'

38,900,000

'

'

'

229,100,000

38,900,000

'

'

Total AECOM equity

116,600,000

'

'

'

106,800,000

'

'

'

116,600,000

106,800,000

'

'

Noncontrolling interests

74,600,000

'

'

'

40,000,000

'

'

'

74,600,000

40,000,000

'

'

TOTAL STOCKHOLDERS' EQUITY

191,200,000

'

'

'

146,800,000

'

'

'

191,200,000

146,800,000

'

'

TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY

420,300,000

'

'

'

185,700,000

'

'

'

420,300,000

185,700,000

'

'

Joint ventures summarized financial information

'

'

'

'

'

'

'

'

'

'

'

'

Total revenue

'

'

'

'

'

'

'

'

614,500,000

490,900,000

468,600,000

'

Unconsolidated Joint Ventures [Member]

'

'

'

'

'

'

'

'

'

'

'

'

Financial information

'

'

'

'

'

'

'

'

'

'

'

'

Current assets

539,600,000

'

'

'

525,500,000

'

'

'

539,600,000

525,500,000

'

'

Non-current assets

273,700,000

'

'

'

98,700,000

'

'

'

273,700,000

98,700,000

'

'

TOTAL ASSETS

813,300,000

'

'

'

624,200,000

'

'

'

813,300,000

624,200,000

'

'

Current liabilities

397,900,000

'

'

'

384,100,000

'

'

'

397,900,000

384,100,000

'

'

Non-current liabilities

91,000,000

'

'

'

17,500,000

'

'

'

91,000,000

17,500,000

'

'

TOTAL LIABILITIES

488,900,000

'

'

'

401,600,000

'

'

'

488,900,000

401,600,000

'

'

TOTAL STOCKHOLDERS' EQUITY

324,400,000

'

'

'

222,600,000

'

'

'

324,400,000

222,600,000

'

'

TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY

813,300,000

'

'

'

624,200,000

'

'

'

813,300,000

624,200,000

'

'

AECOM's investment in joint ventures

142,900,000

'

'

'

106,400,000

'

'

'

142,900,000

106,400,000

'

'

Joint ventures summarized financial information

'

'

'

'

'

'

'

'

'

'

'

'

Total revenue

'

'

'

'

'

'

'

'

2,000,000,000

2,100,000,000

2,000,000,000

'

Total operating income

'

'

'

'

'

'

'

'

57,700,000

70,100,000

127,500,000

'

Summary of AECOM's equity in earnings of unconsolidated joint ventures:

'

'

'

'

'

'

'

'

'

'

'

'

Pass through joint ventures

'

'

'

'

'

'

'

'

10,200,000

6,400,000

5,200,000

'

Other joint ventures

'

'

'

'

'

'

'

'

47,700,000

17,900,000

43,400,000

'

Total

'

'

'

'

'

'

'

'

57,900,000

24,300,000

48,600,000

'

Consolidated joint venture during the year ended 09/30/2014

'

'

'

'

'

'

'

'

'

'

'

'

Financial information

'

'

'

'

'

'

'

'

'

'

'

'

TOTAL ASSETS

207,800,000

'

'

'

'

'

'

'

207,800,000

'

'

'

TOTAL LIABILITIES

48,100,000

'

'

'

'

'

'

'

48,100,000

'

'

'

Equity in earnings of unconsolidated joint ventures

'

'

'

'

'

'

'

'

'

'

'

'

Gain (loss) from equity in earnings of joint ventures due to the change in control

'

'

'

'

'

'

'

'

37,400,000

'

'

'

Gain (loss) from equity in earnings of joint ventures due to the change in control, net of tax

'

'

'

'

'

'

'

'

23,400,000

'

'

'

Fair value of the previously held equity interest, excluding control premium

$58,000,000

'

'

'

'

'

'

'

$58,000,000

'

'

'

Pension_Plans_Details

Pension Plans (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2010
Amounts recognized in the consolidated balance sheets:	'	'	'	'
Other long-term liabilities	($221.30)	($192.70)	'	'
United States Pension Plan of US Entity, Defined Benefit [Member]	'	'	'	'
Pension plans.	'	'	'	'
Number of completed calendar years from 1994 through 2003 considered to set the maximum compensation used to determine pension benefits	'10 years	'	'	'
Change in benefit obligation:	'	'	'	'
Benefit obligation at beginning of year	180.3	192.9	192.9	171
Participant contributions	0.4	0.4	0.6	'
Interest cost	7.8	6.6	7.7	'
Benefits paid	-12.8	-11	-10	'
Actuarial (gain) loss	23.2	-8.6	23.6	'
Net transfer in/(out)/acquisitions	18.1	'	'	'
Benefit obligation at end of year	217	180.3	192.9	171
Change in plan assets	'	'	'	'
Fair value of plan assets at beginning of year	119.8	112.3	112.3	91.5
Actual return on plan assets	14.2	11.3	17	'
Employer contributions	4.9	6.8	13.2	'
Participant contributions	0.4	0.4	0.6	'
Benefits paid	-12.8	-11	-10	'
Net transfer in/(out)/acquisitions	13.2	'	'	'
Fair value of plan assets at end of year	139.7	119.8	112.3	91.5
Reconciliation of funded status:	'	'	'	'
Funded status at end of year	-77.3	-60.5	-80.6	'
Net amount recognized in the balance sheet	-77.3	-60.5	-80.6	'
Amounts recognized in the consolidated balance sheets:	'	'	'	'
Accrued expenses and other current liabilities	-1.7	-1.4	-1.7	'
Other long-term liabilities	-75.6	-59.1	-78.9	'
Net amount recognized in the balance sheet	-77.3	-60.5	-80.6	'
Reconciliation of amounts in consolidated statements of stockholders' equity:	'	'	'	'
Net (loss)	-113	-99.4	-115.1	'
Total recognized in accumulated other comprehensive (loss)	-113	-99.4	-115.1	'
Foreign Pension Plan, Defined Benefit [Member]	'	'	'	'
Change in benefit obligation:	'	'	'	'
Benefit obligation at beginning of year	622.1	574	574	504.3
Service costs	0.7	0.9	1.1	'
Participant contributions	0.2	0.3	0.3	'
Interest cost	27.9	23.8	25.6	'
Benefits paid	-23.3	-18.8	-25.7	'
Actuarial (gain) loss	62.3	49	50.3	'
Plan settlements	-2	-5.7	-2.4	'
Foreign currency translation (gain) loss	-11.3	-1.4	20.5	'
Benefit obligation at end of year	676.6	622.1	574	504.3
Change in plan assets	'	'	'	'
Fair value of plan assets at beginning of year	489.9	462.4	462.4	417.3
Actual return on plan assets	60.4	37.4	39	'
Employer contributions	16.4	16.2	17.2	'
Participant contributions	0.2	0.3	0.3	'
Benefits paid	-23.3	-18.8	-25.7	'
Plan settlements	-2	-5.7	-2.4	'
Foreign currency translation (loss) gain	-9	-1.9	16.7	'
Fair value of plan assets at end of year	532.6	489.9	462.4	417.3
Reconciliation of funded status:	'	'	'	'
Funded status at end of year	-144	-132.2	-111.6	'
Net amount recognized in the balance sheet	-144	-132.2	-111.6	'
Amounts recognized in the consolidated balance sheets:	'	'	'	'
Other non-current assets	1.1	0.6	'	'
Other long-term liabilities	-145.1	-132.8	-111.6	'
Net amount recognized in the balance sheet	-144	-132.2	-111.6	'
Reconciliation of amounts in consolidated statements of stockholders' equity:	'	'	'	'
Prior service credit	5.8	6	6.2	'
Net (loss)	-190.1	-170.7	-143.2	'
Total recognized in accumulated other comprehensive (loss)	($184.30)	($164.70)	($137)	'

Pension_Plans_Details_2

Pension Plans (Details 2) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Pension plans.	'	'	'
Amount, net of applicable deferred income taxes, included in other comprehensive income arising from a change in net prior service cost and net gain/loss	$24,161,000	$14,582,000	$41,778,000
Pension Plan, Defined Benefit [Member]	'	'	'
Pension plans.	'	'	'
Amount, net of applicable deferred income taxes, included in other comprehensive income arising from a change in net prior service cost and net gain/loss	7,600,000	2,600,000	9,000,000
United States Pension Plan of US Entity, Defined Benefit [Member]	'	'	'
Pension plans.	'	'	'
Interest cost on projected benefit obligation	7,800,000	6,600,000	7,700,000
Expected return on plan assets	-8,600,000	-8,500,000	-8,400,000
Amortization of net loss	4,000,000	4,300,000	3,100,000
Net periodic cost	3,200,000	2,400,000	2,400,000
Amounts included in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost during the next fiscal year	'	'	'
Amortization of net actuarial losses	-4,300,000	'	'
Total	-4,300,000	'	'
Additional year-end information for pension plans with accumulated benefit obligations in excess of plan assets	'	'	'
Projected benefit obligation	217,000,000	180,300,000	192,900,000
Accumulated benefit obligation	217,000,000	180,300,000	192,900,000
Fair values of plan assets	139,700,000	119,800,000	112,300,000
Expected employer contributions in next fiscal year	5,400,000	'	'
Expected future benefit payments	'	'	'
2015	12,200,000	'	'
2016	14,900,000	'	'
2017	13,400,000	'	'
2018	12,900,000	'	'
2019	13,400,000	'	'
2020-2024	68,300,000	'	'
Total	135,100,000	'	'
Weighted-average assumptions to determine benefit obligation:	'	'	'
Discount rate (as a percent)	4.00%	4.40%	3.50%
Weighted-average assumptions to determine net periodic benefit cost:	'	'	'
Discount rate (as a percent)	4.40%	3.50%	4.65%
Expected long-term rate of return on plan assets (as a percent)	7.50%	7.50%	7.50%
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	100.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	100.00%	100.00%	'
United States Pension Plan of US Entity, Defined Benefit [Member] | Equity Securities [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	45.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	58.00%	49.00%	'
United States Pension Plan of US Entity, Defined Benefit [Member] | Debt Securities [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	42.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	31.00%	34.00%	'
United States Pension Plan of US Entity, Defined Benefit [Member] | Cash and Cash Equivalents [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	3.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	1.00%	1.00%	'
United States Pension Plan of US Entity, Defined Benefit [Member] | Property and Other [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	10.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	10.00%	16.00%	'
Foreign Pension Plan, Defined Benefit [Member]	'	'	'
Pension plans.	'	'	'
Service costs	700,000	900,000	1,100,000
Interest cost on projected benefit obligation	27,900,000	23,800,000	25,600,000
Expected return on plan assets	-26,100,000	-22,700,000	-25,300,000
Amortization of prior service costs	-200,000	-200,000	-200,000
Amortization of net loss	4,900,000	4,000,000	2,300,000
Settlement loss recognized	400,000	2,600,000	500,000
Net periodic cost	7,600,000	8,500,000	4,000,000
Amounts included in accumulated other comprehensive loss that are expected to be recognized as components of net periodic benefit cost during the next fiscal year	'	'	'
Amortization of prior service credit	-200,000	-200,000	-200,000
Amortization of net actuarial losses	-6,200,000	'	'
Total	-6,000,000	'	'
Additional year-end information for pension plans with accumulated benefit obligations in excess of plan assets	'	'	'
Projected benefit obligation	658,500,000	601,700,000	574,000,000
Accumulated benefit obligation	656,300,000	599,800,000	570,600,000
Fair values of plan assets	513,400,000	469,000,000	462,400,000
Expected employer contributions in next fiscal year	17,000,000	'	'
Expected future benefit payments	'	'	'
2015	26,500,000	'	'
2016	21,900,000	'	'
2017	26,300,000	'	'
2018	29,100,000	'	'
2019	25,800,000	'	'
2020-2024	153,300,000	'	'
Total	$282,900,000	'	'
Weighted-average assumptions to determine benefit obligation:	'	'	'
Discount rate (as a percent)	3.94%	4.44%	4.39%
Salary increase rate (as a percent)	2.38%	2.58%	2.36%
Weighted-average assumptions to determine net periodic benefit cost:	'	'	'
Discount rate (as a percent)	4.44%	4.39%	5.12%
Salary increase rate (as a percent)	2.58%	2.36%	2.65%
Expected long-term rate of return on plan assets (as a percent)	5.40%	5.11%	5.65%
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	100.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	100.00%	100.00%	'
Foreign Pension Plan, Defined Benefit [Member] | Equity Securities [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	1.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	28.00%	28.00%	'
Foreign Pension Plan, Defined Benefit [Member] | Debt Securities [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	47.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	33.00%	37.00%	'
Foreign Pension Plan, Defined Benefit [Member] | Cash and Cash Equivalents [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	1.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	3.00%	4.00%	'
Foreign Pension Plan, Defined Benefit [Member] | Property and Other [Member]	'	'	'
Target Allocations by Asset Category	'	'	'
Target Allocations by Asset Category (as a percent)	51.00%	'	'
Percentage of Plan Assets by Asset Category	'	'	'
Plan Assets by Asset Category (as a percent)	36.00%	31.00%	'

Pension_Plans_Details_3

Pension Plans (Details 3) (Pension Plan, Defined Benefit [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2011
Post-retirement plan	'	'	'
Fair values of plan assets	$672.30	$609.70	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	672.3	609.7	'
Cash and Cash Equivalents [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	7.9	11	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	7.9	11	'
Diversified Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	159.3	108.6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	159.3	108.6	'
Equity Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	220.3	192.4	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	220.3	192.4	'
Fixed Income Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	219.3	220.6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	219.3	220.6	'
Hedge Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	27.9	25	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	27.9	25	'
Assets Held by Insurance Company [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	37.6	46.1	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	37.6	46.1	'
Real Estate [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	'	6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	'	6	'
Fair Value, Inputs, Level 1 [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	3.4	11	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	3.4	11	'
Fair Value, Inputs, Level 1 [Member] | Cash and Cash Equivalents [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	3.4	11	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	3.4	11	'
Fair Value, Inputs, Level 2 [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	655.2	586.1	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	655.2	586.1	'
Fair Value, Inputs, Level 2 [Member] | Cash and Cash Equivalents [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	4.5	'	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	4.5	'	'
Fair Value, Inputs, Level 2 [Member] | Diversified Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	159.3	108.6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	159.3	108.6	'
Fair Value, Inputs, Level 2 [Member] | Equity Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	220.3	192.4	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	220.3	192.4	'
Fair Value, Inputs, Level 2 [Member] | Fixed Income Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	219.3	220.6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	219.3	220.6	'
Fair Value, Inputs, Level 2 [Member] | Hedge Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	14.2	12.4	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	14.2	12.4	'
Fair Value, Inputs, Level 2 [Member] | Assets Held by Insurance Company [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	37.6	46.1	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	37.6	46.1	'
Fair Value, Inputs, Level 2 [Member] | Real Estate [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	'	6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at end of year	'	6	'
Fair Value, Inputs, Level 3 [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	13.7	12.6	'
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at beginning of year	12.6	10.6	'
Defined Benefit Plan, Actual Return on Plan Assets Still Held	1.1	2	'
Fair value of plan assets at end of year	13.7	12.6	'
Fair Value, Inputs, Level 3 [Member] | Hedge Funds [Member]	'	'	'
Post-retirement plan	'	'	'
Fair values of plan assets	13.7	12.6	10.6
Changes in the fair value of Level 3 assets	'	'	'
Fair value of plan assets at beginning of year	12.6	'	10.6
Defined Benefit Plan, Actual Return on Plan Assets Still Held	1.1	2	'
Fair value of plan assets at end of year	$13.70	$12.60	$10.60

Debt_Details

Debt (Details) (USD $)

12 Months Ended

12 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

12 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Jun. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Jul. 31, 2010

Sep. 30, 2014

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2014

Jul. 31, 2010

Sep. 30, 2014

Sep. 30, 2013

Jul. 31, 2010

Sep. 30, 2014

Sep. 30, 2013

Jul. 31, 2011

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Notes Payable to Banks [Member]

Notes Payable to Banks [Member]

Notes Payable to Banks [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks June 2013 Agreement [Member]

Notes Payable to Banks September 2011 Agreement [Member]

Notes Payable to Banks September 2011 Agreement [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes [Member]

Senior Notes 5.43 Percent Series A Due July 2020 [Member]

Senior Discount Notes 1.00 Percent Series B Due July 2022 [Member]

Senior Discount Notes 1.00 Percent Series B Due July 2022 [Member]

Senior Discount Notes 1.00 Percent Series B Due July 2022 [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Line of Credit [Member]

Other Debt [Member]

Other Debt [Member]

Unsecured Credit Facilities [Member]

Unsecured Credit Facilities [Member]

Minimum [Member]

Base Rate [Member]

Base Rate [Member]

Base Rate [Member]

Debt Instrument Variable Rate Base Eurocurrency Rate [Member]

Debt Instrument Variable Rate Base Eurocurrency Rate [Member]

Debt Instrument Variable Rate Base Eurocurrency Rate [Member]

Minimum [Member]

Maximum

Minimum [Member]

Base Rate [Member]

Base Rate [Member]

Debt Instrument Variable Rate Base Eurocurrency Rate [Member]

Debt Instrument Variable Rate Base Eurocurrency Rate [Member]

item

Maximum

Minimum [Member]

Maximum

Minimum [Member]

item

Maximum

Minimum [Member]

Maximum

Minimum [Member]

Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total debt

$1,004,000,000

$1,173,300,000

'

$712,500,000

$750,000,000

'

'

'

'

'

'

'

'

'

'

'

'

$263,900,000

$260,200,000

'

'

'

'

'

'

$0

$114,700,000

'

'

'

'

'

'

'

$27,600,000

$48,400,000

'

'

Less: Current portion of debt and short-term borrowings

-64,400,000

-84,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term debt, less current portion

939,565,000

1,089,060,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Scheduled maturities of debt:

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2015

64,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2016

38,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2017

37,700,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2018

600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Thereafter

263,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total debt

1,004,000,000

1,173,300,000

'

712,500,000

750,000,000

'

'

'

'

'

'

'

'

'

'

'

'

263,900,000

260,200,000

'

'

'

'

'

'

0

114,700,000

'

'

'

'

'

'

'

27,600,000

48,400,000

'

'

Debt agreements

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Principal amount

'

'

'

'

'

'

'

750,000,000

'

'

'

'

'

'

'

'

300,000,000

'

'

'

'

175,000,000

'

'

125,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional borrowings available

'

'

'

'

'

'

'

100,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repayment of indebtedness

1,998,882,000

2,156,399,000

1,550,996,000

'

'

'

'

'

'

'

'

'

'

'

675,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate, basis spread (as a percent)

'

'

'

'

'

'

'

'

'

1.25%

0.13%

'

2.25%

1.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.25%

0.13%

2.25%

1.13%

'

'

'

'

Interest rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.43%

'

'

1.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Description of interest rate basis

'

'

'

'

'

'

'

'

'Base Rate

'

'

'Eurodollar Rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Average interest rate (as a percent)

'

'

'

'

'

'

1.66%

'

'

'

'

'

'

'

'

1.98%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Final principal payment

'

'

'

'

'

'

600,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective interest rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.62%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of debt instrument

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

287,400,000

269,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Proceeds from sale of senior notes

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

249,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of subsidiary guarantors

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Borrowing capacity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,050,000,000

'

'

'

'

'

'

'

'

'

'

Contingent increase to maximum borrowing capacity under the credit facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,250,000,000

'

'

'

'

'

'

'

'

'

'

Percentage of commitment fee

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.35%

0.13%

'

'

'

'

'

'

'

'

Outstanding letters of credit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

12,100,000

35,500,000

'

'

'

'

'

'

'

301,000,000

236,400,000

'

'

Remaining borrowing capacity under the credit facility

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,037,900,000

'

'

'

'

'

'

'

'

'

'

327,400,000

331,800,000

Actual consolidated leverage ratio

2.55

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Maximum consolidated leverage ratio

3

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net worth threshold, base amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,200,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net worth threshold, percentage of the consolidated net income for each fiscal quarter commencing with the specified period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

40.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Actual net worth of the entity

2,186,517,000

2,021,443,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,200,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net worth threshold

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,700,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Average effective interest rate on total borrowings, including the effects of swaps (as a percent)

2.80%

3.00%

3.10%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$88,900,000

$85,200,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Details)

12 Months Ended

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Cash Flow Hedging [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Not Designated as Hedging Instrument [Member]

Interest Rate Swap [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Cash Flow Hedging [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Foreign Exchange Forward [Member]

Options Held [Member]

Options Held [Member]

USD ($)

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swap June 2018 [Member]

Interest Rate Swap September 2015 [Member]

Interest Rate Swap September 2015 [Member]

Interest Rate Swap December 2014 [Member]

Interest Rate Swap December 2014 [Member]

Interest Rate Swap December 2013 [Member]

Foreign Exchange Option [Member]

Foreign Exchange Option [Member]

Foreign Exchange Option [Member]

United States of America, Dollars

United States of America, Dollars

United States of America, Dollars

United States of America, Dollars

Brazil, Brazil Real

Brazil, Brazil Real

Brazil, Brazil Real

Brazil, Brazil Real

Brazil, Brazil Real

Brazil, Brazil Real

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

GBP (£)

USD ($)

BRL

Long [Member]

Long [Member]

Short [Member]

Short [Member]

Long [Member]

Long [Member]

Long [Member]

Long [Member]

Short [Member]

Short [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

BRL

USD ($)

BRL

USD ($)

BRL

Derivative financial instruments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective portion of derivatives before tax effect

$3,000,000

($2,400,000)

($500,000)

($8,400,000)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective portion of derivatives expected to be reclassified from accumulated other comprehensive loss to interest expense, net

4,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notional Amount

'

'

'

'

300,000,000

250,000,000

250,000,000

200,000,000

200,000,000

150,000,000

'

'

'

69,500,000

171,800,000

71,500,000

174,200,000

400,000

1,100,000

1,800,000

4,000,000

3,600,000

8,200,000

'

'

Fixed Rate (as a percent)

'

'

'

'

1.63%

0.95%

0.95%

0.68%

0.68%

0.55%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notional principal of derivative exchange contracts

'

'

'

'

'

'

'

'

'

'

£ 0

$900,000

2,100,000

'

'

'

'

'

'

'

'

'

'

$0

$0

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Fair values of outstanding derivative instruments	'	'	'
Derivative assets	$4.80	$1.70	'
Derivative liabilities	8.5	5.2	'
Interest Rate Swap [Member] | Cash Flow Hedging [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Increase in Losses Recognized in Accumulated Other Comprehensive Loss on Derivatives Before Tax Effect (Effective Portion)	3	'	'
Designated as Hedging Instrument [Member] | Foreign Exchange Option [Member] | Cash Flow Hedging [Member] | Cost of Sales [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Losses Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	-0.1	'	'
Losses Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	'	-0.1	-0.1
Designated as Hedging Instrument [Member] | Foreign Exchange Option [Member] | Prepaid Expenses and Other Current Assets [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative assets	'	0.1	'
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Increase in Losses Recognized in Accumulated Other Comprehensive Loss on Derivatives Before Tax Effect (Effective Portion)	-2.4	-0.5	-8.4
Losses Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	0	'	'
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | Interest Expense [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Losses Reclassified from Accumulated Other Comprehensive Loss into Income (Effective Portion)	-2.9	-3.1	-2.2
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Accrued Expenses and Other Current Liabilities [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative liabilities	4.8	2.6	'
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other Long Term Liabilities [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative liabilities	'	1.1	'
Designated as Hedging Instrument [Member] | Interest Rate Swap [Member] | Other Noncurrent Assets [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative assets	1.7	'	'
Not Designated as Hedging Instrument [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Non designated derivatives, Gains/(Losses) Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	-0.1	-5	4.2
Not Designated as Hedging Instrument [Member] | Options Held [Member] | Cost of Sales [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Non designated derivatives, Gains/(Losses) Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	'	-0.3	-0.1
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | General and Administrative Expense [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Non designated derivatives, Gains/(Losses) Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	-0.1	-4.7	4.2
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Cost of Sales [Member]	'	'	'
Effect of derivative instruments on income and other comprehensive income	'	'	'
Non designated derivatives, Gains/(Losses) Recognized in Income on Derivatives (Amount Excluded from Effectiveness Testing and Ineffective Portion)	'	'	0.1
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Prepaid Expenses and Other Current Assets [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative assets	3.1	1.6	'
Not Designated as Hedging Instrument [Member] | Foreign Exchange Forward [Member] | Accrued Expenses and Other Current Liabilities [Member]	'	'	'
Fair values of outstanding derivative instruments	'	'	'
Derivative liabilities	$3.70	$1.50	'

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $)	Sep. 30, 2014	Sep. 30, 2013
In Millions, unless otherwise specified
Estimate of Fair Value Measurement [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	$4.80	$1.70
Total liabilities	8.5	5.2
Estimate of Fair Value Measurement [Member] | Foreign Exchange Option [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	1.7	0.1
Estimate of Fair Value Measurement [Member] | Foreign Exchange Forward [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	3.1	1.6
Total liabilities	3.7	1.5
Estimate of Fair Value Measurement [Member] | Interest Rate Swap [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total liabilities	4.8	3.7
Fair Value, Inputs, Level 2 [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	4.8	1.7
Total liabilities	8.5	5.2
Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Option [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	1.7	0.1
Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total assets	3.1	1.6
Total liabilities	3.7	1.5
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swap [Member]	'	'
Non-pension financial assets and liabilities measured at fair value	'	'
Total liabilities	$4.80	$3.70

Leases_Details

Leases (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Leases, additional disclosures	'	'	'
Rent expense for all leases	$210.40	$225.40	$237.40
Amounts payable under non-cancelable operating lease commitments	'	'	'
2015	181.4	'	'
2016	154.8	'	'
2017	126.4	'	'
2018	102.6	'	'
2019	86.1	'	'
Thereafter	234.7	'	'
Total	$886	'	'

Other_Financial_Information_De

Other Financial Information (Details) (USD $)	Sep. 30, 2014	Sep. 30, 2013
Accrued expenses	'	'
Accrued salaries and benefits	$400,600,000	$410,600,000
Accrued contract costs	446,400,000	404,200,000
Other accrued expenses	117,600,000	100,500,000
Total accrued expenses	964,627,000	915,282,000
Accrued contract costs related to professional liability accruals	120,200,000	121,300,000
Other long-term liabilities	'	'
Pension liabilities (Note 8)	221,300,000	192,700,000
Reserve for uncertain tax positions (Note 17)	52,600,000	60,200,000
Other	181,700,000	196,000,000
Total other long-term liabilities	$455,563,000	$448,920,000

Reclassifications_out_of_Accum1

Reclassifications out of Accumulated Other Comprehensive Loss (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Accumulated balances	'	'	'
Balance at the beginning of the period	($261,299,000)	($179,200,000)	($187,600,000)
Other comprehensive income before reclassification	-103,100,000	-89,200,000	4,100,000
Amounts reclassified from accumulated other comprehensive loss, actuarial losses, net of tax	6,100,000	5,300,000	3,000,000
Balance at the end of the period	-356,602,000	-261,299,000	-179,200,000
Actuarial losses	'	'	'
Accumulated balances	'	'	'
Balance at the beginning of the period	-192,800,000	-178,200,000	-136,500,000
Other comprehensive income before reclassification	-30,300,000	-19,900,000	-44,700,000
Amounts reclassified from accumulated other comprehensive loss, actuarial losses, net of tax	6,100,000	5,300,000	3,000,000
Balance at the end of the period	-217,000,000	-192,800,000	-178,200,000
Accumulated Translation Adjustment [Member]	'	'	'
Accumulated balances	'	'	'
Balance at the beginning of the period	-66,400,000	2,700,000	-51,100,000
Other comprehensive income before reclassification	-71,400,000	-69,100,000	53,800,000
Balance at the end of the period	-137,800,000	-66,400,000	2,700,000
Cash flow hedges	'	'	'
Accumulated balances	'	'	'
Balance at the beginning of the period	-2,100,000	-3,700,000	'
Other comprehensive income before reclassification	-1,400,000	-200,000	-5,000,000
Amounts reclassified from accumulated other comprehensive loss, cash flow hedge losses, net of tax	1,700,000	1,800,000	1,300,000
Balance at the end of the period	($1,800,000)	($2,100,000)	($3,700,000)

Reclassifications_out_of_Accum2

Reclassifications out of Accumulated Other Comprehensive Loss (Details 2) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Amounts Reclassified from Accumulated Other Comprehensive Loss	'	'	'	'	'	'	'	'	'	'	'
Income before income tax expense	$94,300	$82,800	$57,700	$80,000	$114,000	$101,400	$68,700	$51,700	$314,788	$335,774	$17,483
Income tax expense	-29,600	-13,700	-15,200	-23,500	-35,800	-30,100	-14,000	-12,700	-82,024	-92,578	-74,416
Net income (loss)	64,700	69,100	42,500	56,500	78,200	71,300	54,700	39,000	232,764	243,196	-56,933
Cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Amounts Reclassified from Accumulated Other Comprehensive Loss	'	'	'	'	'	'	'	'	'	'	'
Income tax expense	'	'	'	'	'	'	'	'	-1,200	-1,200	-900
Net income (loss)	'	'	'	'	'	'	'	'	1,700	1,800	1,300
Cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income [Member] | Interest Expense [Member]	'	'	'	'	'	'	'	'	'	'	'
Amounts Reclassified from Accumulated Other Comprehensive Loss	'	'	'	'	'	'	'	'	'	'	'
Income before income tax expense	'	'	'	'	'	'	'	'	2,900	3,000	2,200
Actuarial losses | Reclassification out of Accumulated Other Comprehensive Income [Member]	'	'	'	'	'	'	'	'	'	'	'
Amounts Reclassified from Accumulated Other Comprehensive Loss	'	'	'	'	'	'	'	'	'	'	'
Income tax expense	'	'	'	'	'	'	'	'	-2,600	-2,700	-1,700
Net income (loss)	'	'	'	'	'	'	'	'	6,100	5,300	3,000
Actuarial losses | Reclassification out of Accumulated Other Comprehensive Income [Member] | Cost of Sales and General and Administrative Expense [Member]	'	'	'	'	'	'	'	'	'	'	'
Amounts Reclassified from Accumulated Other Comprehensive Loss	'	'	'	'	'	'	'	'	'	'	'
Income before income tax expense	'	'	'	'	'	'	'	'	$8,700	$8,000	$4,700

Stock_Plans_Details

Stock Plans (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2010
Deferred Compensation Plan	'	'	'	'
Compensation expense related to employer contributions under defined contribution plans, including the DCP	$14.40	$14.60	$15.90	'
Employee Stock Option [Member]	'	'	'	'
Stock Incentive Plans	'	'	'	'
Securities available for future issuance (in shares)	19,800,000	'	'	'
Expiration term of unexercised options	'7 years	'	'	'
Weighted average grant-date fair value of stock options granted (in dollars per share)	$7.83	'	'	'
Number of Options	'	'	'	'
Balance at the beginning of the period (in shares)	1,600,000	2,500,000	'	2,900,000
Granted (in shares)	600,000	'	'	'
Exercised (in shares)	-500,000	-800,000	-400,000	'
Cancelled (in shares)	-100,000	-100,000	'	'
Balance at the end of the period (in shares)	1,600,000	1,600,000	2,500,000	2,900,000
Exercisable at the end of the period (in shares)	900,000	1,400,000	2,100,000	'
Stock options, Weighted Average Exercise Price	'	'	'	'
Balance at the beginning of the period (in dollars per share)	$24.73	$22.81	'	$21.38
Granted (in dollars per share)	$31.62	'	'	'
Exercised (in dollars per share)	$23.64	$18.31	$11.40	'
Cancelled (in dollars per share)	$26.87	$26.83	$26.23	'
Balance at the end of the period (in dollars per share)	$27.69	$24.73	$22.81	$21.38
Exercisable at the end of the period (in dollars per share)	$25.16	$24.51	$22.07	'
Restricted and Performance Stock Award [Member]	'	'	'	'
Stock Incentive Plans	'	'	'	'
Securities available for future issuance (in shares)	9,900,000	'	'	'

Stock_Plans_Details_2

Stock Plans (Details 2) (USD $)	12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Compensation expense	'	'	'
Excess tax benefit from share-based payment	$748,000	$1,754,000	$1,254,000
Employee Stock Option [Member]	'	'	'
Options Outstanding	'	'	'
Number outstanding as of end of period (in shares)	1.6	'	'
Weighted Average Remaining Contractual Life	'4 years 8 months 9 days	'	'
Weighted Average Exercise Price (in dollars per share)	$27.69	'	'
Aggregate Intrinsic Value (in millions)	8,500,000	'	'
Options Exercisable	'	'	'
Number Exercisable at the end of the period (in shares)	0.9	'	'
Weighted Average Remaining Contractual Life	'1 year 7 months 24 days	'	'
Weighted Average Exercise Price (in dollars per share)	$25.16	'	'
Stock Incentive Plans, additional disclosures	'	'	'
Remaining contractual life of options outstanding, low end of range	'11 days	'	'
Remaining contractual life of options outstanding, high end of range	'9 years 5 months 5 days	'	'
Aggregate intrinsic value of stock options exercised	4,300,000	7,900,000	3,900,000
Compensation expense	'	'	'
Weighted average grant-date fair value of stock options granted (in dollars per share)	$7.83	'	'
Excess tax benefit from share-based payment	700,000	1,800,000	1,300,000
Performance Earnings Program [Member]	'	'	'
Compensation expense	'	'	'
Unrecognized compensation expense	62,400,000	'	'
Period of recognition of unrecognized compensation expense	'3 years	'	'
Weighted average grant-date fair value of stock options granted (in dollars per share)	$29.32	$22.27	$20.58
Performance period over which objectives must be met to qualify for an award grant	'3 years	'	'
Restricted Stock Units (RSUs) [Member]	'	'	'
Compensation expense	'	'	'
Recognized compensation expense	34,400,000	32,600,000	26,600,000
Weighted average grant-date fair value of stock options granted (in dollars per share)	$29.60	$22.83	$20.62
Exercise Price Range from Dollars 21.01 to Dollars 23.94 [Member]	'	'	'
Information concerning outstanding and exercisable options	'	'	'
Exercise price, low end of range (in dollars per share)	$21.01	'	'
Exercise price, high end of range (in dollars per share)	$23.94	'	'
Exercise Price Range from Dollars 21.01 to Dollars 23.94 [Member] | Employee Stock Option [Member]	'	'	'
Options Outstanding	'	'	'
Number outstanding as of end of period (in shares)	0.4	'	'
Weighted Average Remaining Contractual Life	'1 year 2 months 5 days	'	'
Weighted Average Exercise Price (in dollars per share)	$23.46	'	'
Aggregate Intrinsic Value (in millions)	4,100,000	'	'
Options Exercisable	'	'	'
Number Exercisable at the end of the period (in shares)	0.4	'	'
Weighted Average Remaining Contractual Life	'1 year 2 months 5 days	'	'
Weighted Average Exercise Price (in dollars per share)	$23.46	'	'
Exercise Price Range from Dollars 24.45 to Dollars 26.47 [Member]	'	'	'
Information concerning outstanding and exercisable options	'	'	'
Exercise price, low end of range (in dollars per share)	$24.45	'	'
Exercise price, high end of range (in dollars per share)	$28.67	'	'
Exercise Price Range from Dollars 24.45 to Dollars 26.47 [Member] | Employee Stock Option [Member]	'	'	'
Options Outstanding	'	'	'
Number outstanding as of end of period (in shares)	0.5	'	'
Weighted Average Remaining Contractual Life	'2 years 22 days	'	'
Weighted Average Exercise Price (in dollars per share)	$26.24	'	'
Aggregate Intrinsic Value (in millions)	3,600,000	'	'
Options Exercisable	'	'	'
Number Exercisable at the end of the period (in shares)	0.5	'	'
Weighted Average Remaining Contractual Life	'2 years 22 days	'	'
Weighted Average Exercise Price (in dollars per share)	$26.24	'	'
Exercise Price Range from Dollars 30.96 to Dollars 34.00 [Member]	'	'	'
Information concerning outstanding and exercisable options	'	'	'
Exercise price, low end of range (in dollars per share)	$30.96	'	'
Exercise price, high end of range (in dollars per share)	$34	'	'
Exercise Price Range from Dollars 30.96 to Dollars 34.00 [Member] | Employee Stock Option [Member]	'	'	'
Options Outstanding	'	'	'
Number outstanding as of end of period (in shares)	0.7	'	'
Weighted Average Remaining Contractual Life	'9 years 2 months 1 day	'	'
Weighted Average Exercise Price (in dollars per share)	$31.65	'	'
Aggregate Intrinsic Value (in millions)	$800,000	'	'
Options Exercisable	'	'	'
Weighted Average Remaining Contractual Life	'7 months 28 days	'	'
Weighted Average Exercise Price (in dollars per share)	$32.53	'	'

Income_Taxes_Details

Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Income Taxes	'	'	'	'	'	'	'	'	'	'	'
Income (loss) from domestic operations before income tax expense	'	'	'	'	'	'	'	'	$138,200,000	$111,800,000	($89,200,000)
Income from foreign operations before income tax expense	'	'	'	'	'	'	'	'	176,600,000	224,000,000	106,700,000
Current:	'	'	'	'	'	'	'	'	'	'	'
Federal	'	'	'	'	'	'	'	'	5,300,000	30,300,000	29,300,000
State	'	'	'	'	'	'	'	'	3,300,000	9,900,000	2,100,000
Foreign	'	'	'	'	'	'	'	'	46,300,000	59,700,000	63,300,000
Total current income tax expense	'	'	'	'	'	'	'	'	54,900,000	99,900,000	94,700,000
Deferred:	'	'	'	'	'	'	'	'	'	'	'
Federal	'	'	'	'	'	'	'	'	27,700,000	5,800,000	-19,200,000
State	'	'	'	'	'	'	'	'	5,600,000	-10,600,000	600,000
Foreign	'	'	'	'	'	'	'	'	-6,200,000	-2,500,000	-1,700,000
Total deferred income tax (benefit) expense	'	'	'	'	'	'	'	'	27,155,000	-7,210,000	-20,303,000
Total income tax expense	29,600,000	13,700,000	15,200,000	23,500,000	35,800,000	30,100,000	14,000,000	12,700,000	82,024,000	92,578,000	74,416,000
Major elements contributing to the difference between the U.S. federal statutory rate of 35.0% and the effective tax rate	'	'	'	'	'	'	'	'	'	'	'
Tax at federal statutory rate	'	'	'	'	'	'	'	'	110,200,000	117,500,000	6,100,000
State income tax, net of federal benefit	'	'	'	'	'	'	'	'	5,000,000	2,500,000	1,100,000
U.S. income tax credits	'	'	'	'	'	'	'	'	-3,500,000	-10,800,000	-2,900,000
Foreign tax rate differential	'	'	'	'	'	'	'	'	-22,500,000	-9,900,000	-25,400,000
Foreign Research and Experimentation credits	'	'	'	'	'	'	'	'	-3,600,000	-3,900,000	-5,800,000
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	101,100,000
Change in uncertain tax positions	'	'	'	'	'	'	'	'	-4,500,000	-7,300,000	-4,100,000
Valuation allowance	'	'	'	'	'	'	'	'	6,300,000	1,600,000	500,000
Domestic production activities	'	'	'	'	'	'	'	'	-11,700,000	-2,600,000	-1,200,000
Nondeductible transaction costs	'	'	'	'	'	'	'	'	2,800,000	'	1,300,000
Other items, net	'	'	'	'	'	'	'	'	3,500,000	5,500,000	3,700,000
Total income tax expense	$29,600,000	$13,700,000	$15,200,000	$23,500,000	$35,800,000	$30,100,000	$14,000,000	$12,700,000	$82,024,000	$92,578,000	$74,416,000
Major elements contributing to the difference between the U.S. federal statutory rate of 35.0% and the effective tax rate	'	'	'	'	'	'	'	'	'	'	'
Tax at federal statutory rate (as a percent)	'	'	'	'	'	'	'	'	35.00%	35.00%	35.00%
State income tax, net of federal benefit (as a percent)	'	'	'	'	'	'	'	'	1.60%	0.70%	6.30%
U.S. income tax credits (as a percent)	'	'	'	'	'	'	'	'	-1.10%	-3.20%	-16.60%
Foreign tax rate differential (as a percent)	'	'	'	'	'	'	'	'	-7.20%	-2.90%	-145.10%
Foreign Research and Experimentation credits (as a percent)	'	'	'	'	'	'	'	'	-1.10%	-1.10%	-33.30%
Goodwill impairment (as a percent)	'	'	'	'	'	'	'	'	'	'	578.30%
Change in uncertain tax positions (as a percent)	'	'	'	'	'	'	'	'	-1.40%	-2.20%	-23.40%
Valuation allowance (as a percent)	'	'	'	'	'	'	'	'	2.00%	0.50%	2.70%
Domestic production activities (as a percent)	'	'	'	'	'	'	'	'	-3.70%	-0.80%	-6.80%
Nondeductible transaction costs (as a percent)	'	'	'	'	'	'	'	'	0.90%	'	7.60%
Other items, net (as a percent)	'	'	'	'	'	'	'	'	1.10%	1.60%	21.00%
Effective tax rate (as a percent)	'	'	'	'	'	'	'	'	26.10%	27.60%	425.70%

Income_Taxes_Details_2

Income Taxes (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2011
Income Taxes, additional disclosures	'	'	'
Unused state research and development credits which can be carried forward indefinitely	$17.50	'	'
California Enterprise Zone Tax Credits which can be carried forward indefinitely	4.6	'	'
Net deferred tax asset likely to be realized and for which no additional valuation allowance has been provided	340	'	'
Additional valuation allowance provided for, net deferred tax asset which is likely to be realized	47.5	'	'
Undistributed earnings from non-U.S. subsidiaries	976.7	'	'
Liability for unrecognized tax benefits, including potential interest and penalties, net of related tax benefit	52.6	60.2	'
Unrecognized tax benefits that would be included in the effective tax rate if recognized	28.6	'	'
Reconciliation of the beginning and ending amount of gross unrecognized tax benefits	'	'	'
Balance at the beginning of the year	53.7	'	55.8
Gross increase in prior years' tax positions	3.3	7.2	'
Gross decrease in prior years' tax positions	-7.6	-5.6	'
Decrease due to settlement with tax authorities	-2	-1.6	'
Gross increase in current periods tax positions	2.2	3.8	'
Lapse of statute of limitations	-2.1	-5.9	'
Balance at the end of the year	47.5	53.7	55.8
Deferred tax assets:	'	'	'
Compensation and benefit accruals not currently deductible	65.5	74.7	'
Net operating loss carry forwards	69.3	58.1	'
Self insurance reserves	48.8	54.7	'
Research and experimentation and other tax credits	34.2	38.3	'
Pension liability	59.4	58.5	'
Accrued liabilities	63.7	56.1	'
Investments in joint ventures/non-controlled subsidiaries	20.7	13.9	'
State taxes	1.5	0.9	'
Other	4	4.2	'
Total deferred tax assets	367.1	359.4	'
Deferred tax liabilities:	'	'	'
Unearned revenue	-122.9	-139.3	'
Depreciation and amortization	-59.2	-20.1	'
Acquired intangible assets	-14.8	-15.8	'
Total deferred tax liabilities	-196.9	-175.2	'
Valuation allowance	-27.1	-20.8	'
Net deferred tax assets	143.1	163.4	'
Accrued penalties, excluding any related income tax benefits	2.9	2.7	'
Accrued interest, excluding any related income tax benefits	6.2	7.3	'
Tax-deductible goodwill	251.6	283.9	'
Maximum	'	'	'
Deferred tax liabilities:	'	'	'
Period of amortization of goodwill	'15 years	'	'
State and Local Jurisdiction [Member]	'	'	'
Deferred tax liabilities:	'	'	'
Net operating loss carry forwards	230.6	'	'
Foreign Tax Authority [Member]	'	'	'
Deferred tax liabilities:	'	'	'
Net operating loss carry forwards	$260.20	'	'

Earnings_Per_Share_Details

Earnings Per Share (Details)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Share	'	'	'	'	'	'	'	'	'	'	'
Antidilutive potential common shares excluded in computation of diluted loss per share	'	'	'	'	'	'	'	'	'	700,000	'
Denominator for basic earnings per share (in shares)	98,100,000	97,500,000	97,000,000	96,300,000	98,000,000	99,300,000	100,400,000	104,800,000	97,226,000	100,618,000	111,875,000
Potential common shares (in shares)	'	'	'	'	'	'	'	'	1,500,000	1,300,000	'
Denominator for diluted earnings per share (in shares)	99,700,000	99,000,000	98,300,000	97,600,000	99,700,000	100,800,000	101,800,000	105,500,000	98,657,000	101,942,000	111,875,000

Commitments_and_Contingencies_

Commitments and Contingencies (Details)	0 Months Ended		12 Months Ended		6 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Jun. 17, 2014	Sep. 30, 2014	Sep. 30, 2014	Sep. 30, 2006	Mar. 31, 2014	Jun. 17, 2014
	AUD	Standby Letters of Credit [Member]	AECOM Australia [Member]	AECOM Australia [Member]	RCM applicants	Portigon AG
		USD ($)	item	AUD	AUD	AUD
Commitments and Contingencies	'	'	'	'	'	'
Contingency liability of general and professional liability insurance programs and for payment and performance guarantees	'	$313.10	'	'	'	'
Proceeds from initial public offering (IPO)	'	'	'	700	'	'
Bank loan	'	'	'	1,400	'	'
Number of initial public offering investors	'	'	770	'	'	'
Damages claimed by applicants	'	'	'	'	1,680	76
Securities acquired by investors	155	'	'	'	'	'

Reportable_Segments_and_Geogra1

Reportable Segments and Geographic Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
									item
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Revenue	$2,562,500,000	$1,968,200,000	$1,872,200,000	$1,953,900,000	$2,079,100,000	$2,067,500,000	$1,989,600,000	$2,017,300,000	$8,356,783,000	$8,153,495,000	$8,218,180,000
Revenue, net of other direct costs	'	'	'	'	'	'	'	'	4,855,600,000	4,977,000,000	5,183,900,000
Gross profit	129,100,000	108,500,000	87,400,000	78,200,000	140,200,000	131,800,000	99,900,000	78,100,000	403,176,000	449,988,000	421,859,000
Equity in earnings of joint ventures	8,400,000	6,000,000	7,400,000	36,100,000	6,400,000	4,100,000	7,900,000	5,900,000	57,924,000	24,319,000	48,650,000
General and administrative expenses	-15,500,000	-15,100,000	-26,400,000	-23,900,000	-23,900,000	-24,000,000	-27,300,000	-22,100,000	-80,908,000	-97,318,000	-80,903,000
Acquisition and integration expense	19,500,000	7,800,000	'	'	'	'	'	'	-27,310,000	'	'
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	-336,000,000
Operating income (loss)	102,500,000	91,600,000	68,400,000	90,400,000	122,700,000	111,900,000	80,500,000	61,900,000	352,882,000	376,989,000	53,606,000
Assets	6,123,377,000	'	'	'	5,665,623,000	'	'	'	6,123,377,000	5,665,623,000	'
Gross profit as a % of revenue	'	'	'	'	'	'	'	'	4.80%	5.50%	5.10%
Gross profit as a % of revenue, net of other direct costs	'	'	'	'	'	'	'	'	8.30%	9.00%	8.10%
Number of reportable segments	'	'	'	'	'	'	'	'	2	'	'
Corporate, Non-Segment [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
General and administrative expenses	'	'	'	'	'	'	'	'	-80,900,000	-97,300,000	-80,900,000
Acquisition and integration expense	'	'	'	'	'	'	'	'	-27,300,000	'	'
Operating income (loss)	'	'	'	'	'	'	'	'	-108,200,000	-97,300,000	-80,900,000
Intersegment Eliminations [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Assets	365,000,000	'	'	'	240,100,000	'	'	'	365,000,000	240,100,000	'
Professional Technical Services [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	7,609,900,000	7,242,900,000	7,276,900,000
Revenue, net of other direct costs	'	'	'	'	'	'	'	'	4,462,700,000	4,416,400,000	4,607,300,000
Gross profit	'	'	'	'	'	'	'	'	365,200,000	416,900,000	423,800,000
Equity in earnings of joint ventures	'	'	'	'	'	'	'	'	41,400,000	12,300,000	16,800,000
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	-155,000,000
Operating income (loss)	'	'	'	'	'	'	'	'	'	'	285,600,000
Gross profit as a % of revenue	'	'	'	'	'	'	'	'	4.80%	5.80%	5.80%
Gross profit as a % of revenue, net of other direct costs	'	'	'	'	'	'	'	'	8.20%	9.40%	9.20%
Professional Technical Services [Member] | Operating Segments [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Operating income (loss)	'	'	'	'	'	'	'	'	406,600,000	429,200,000	'
Assets	5,366,000,000	'	'	'	4,827,500,000	'	'	'	5,366,000,000	4,827,500,000	'
Management Support Services [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	746,900,000	910,600,000	941,300,000
Revenue, net of other direct costs	'	'	'	'	'	'	'	'	392,900,000	560,600,000	576,600,000
Gross profit	'	'	'	'	'	'	'	'	38,000,000	33,100,000	-1,900,000
Equity in earnings of joint ventures	'	'	'	'	'	'	'	'	16,500,000	12,000,000	31,800,000
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	-181,000,000
Operating income (loss)	'	'	'	'	'	'	'	'	'	'	-151,100,000
Gross profit as a % of revenue	'	'	'	'	'	'	'	'	5.10%	3.60%	-0.20%
Gross profit as a % of revenue, net of other direct costs	'	'	'	'	'	'	'	'	9.70%	5.90%	-0.30%
Management Support Services [Member] | Operating Segments [Member]	'	'	'	'	'	'	'	'	'	'	'
Summarized financial information concerning the Company's reportable segments	'	'	'	'	'	'	'	'	'	'	'
Operating income (loss)	'	'	'	'	'	'	'	'	54,500,000	45,100,000	'
Assets	$392,400,000	'	'	'	$598,000,000	'	'	'	$392,400,000	$598,000,000	'

Reportable_Segments_and_Geogra2

Reportable Segments and Geographic Information (Details 2) (USD $)	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	$2,562,500,000	$1,968,200,000	$1,872,200,000	$1,953,900,000	$2,079,100,000	$2,067,500,000	$1,989,600,000	$2,017,300,000	$8,356,783,000	$8,153,495,000	$8,218,180,000
Long-Lived Assets	2,571,200,000	'	'	'	2,390,500,000	'	'	'	2,571,200,000	2,390,500,000	2,390,300,000
UNITED STATES	'	'	'	'	'	'	'	'	'	'	'
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	4,933,700,000	4,829,600,000	4,756,000,000
Long-Lived Assets	1,603,700,000	'	'	'	1,477,300,000	'	'	'	1,603,700,000	1,477,300,000	1,496,800,000
Asia Pacific [Member]	'	'	'	'	'	'	'	'	'	'	'
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	1,338,200,000	1,507,200,000	1,715,100,000
Long-Lived Assets	340,500,000	'	'	'	361,000,000	'	'	'	340,500,000	361,000,000	374,900,000
CANADA	'	'	'	'	'	'	'	'	'	'	'
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	561,100,000	712,000,000	708,800,000
Long-Lived Assets	146,700,000	'	'	'	168,400,000	'	'	'	146,700,000	168,400,000	189,200,000
Europe [Member]	'	'	'	'	'	'	'	'	'	'	'
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	788,200,000	599,400,000	608,200,000
Long-Lived Assets	270,800,000	'	'	'	267,200,000	'	'	'	270,800,000	267,200,000	243,600,000
Other Foreign Countries [Member]	'	'	'	'	'	'	'	'	'	'	'
Geographic Information	'	'	'	'	'	'	'	'	'	'	'
Revenue	'	'	'	'	'	'	'	'	735,600,000	505,300,000	430,100,000
Long-Lived Assets	$209,500,000	'	'	'	$116,600,000	'	'	'	$209,500,000	$116,600,000	$85,800,000

Major_Clients_Details

Major Clients (Details) (Sales Revenue, Services, Net [Member], Customer Concentration Risk [Member])	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Percentage of total revenue	'	'	'
Period for which criteria of threshold percentage for disclosure not met in past	'5 years	'	'
Maximum	'	'	'
Percentage of total revenue	'	'	'
Percentage of revenue accounted for by no other single client (as a percent)	10.00%	'	'
Agencies of U.S. Federal Government [Member]	'	'	'
Percentage of total revenue	'	'	'
Percentage of the Company's revenue (as a percent)	15.00%	18.00%	18.00%
Agencies of U.S. Federal Government [Member] | Management Support Services [Member]	'	'	'
Percentage of total revenue	'	'	'
Percentage of the Company's revenue (as a percent)	3.00%	4.00%	4.00%

Quarterly_Financial_Informatio2

Quarterly Financial Information-Unaudited (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Quarterly Financial Information-Unaudited	'	'	'	'	'	'	'	'	'	'	'
Revenue	$2,562,500	$1,968,200	$1,872,200	$1,953,900	$2,079,100	$2,067,500	$1,989,600	$2,017,300	$8,356,783	$8,153,495	$8,218,180
Cost of revenue	2,433,400	1,859,700	1,784,800	1,875,700	1,938,900	1,935,700	1,889,700	1,939,200	7,953,607	7,703,507	7,796,321
Gross profit	129,100	108,500	87,400	78,200	140,200	131,800	99,900	78,100	403,176	449,988	421,859
Equity in earnings of joint ventures	8,400	6,000	7,400	36,100	6,400	4,100	7,900	5,900	57,924	24,319	48,650
General and administrative expenses	-15,500	-15,100	-26,400	-23,900	-23,900	-24,000	-27,300	-22,100	-80,908	-97,318	-80,903
Acquisition and integration expense	-19,500	-7,800	'	'	'	'	'	'	27,310	'	'
Goodwill impairment	'	'	'	'	'	'	'	'	'	'	-336,000
Income from operations	102,500	91,600	68,400	90,400	122,700	111,900	80,500	61,900	352,882	376,989	53,606
Other income	1,900	1,000	-200	'	1,500	1,200	100	700	2,748	3,522	10,603
Interest expense	-10,100	-9,800	-10,500	-10,400	-10,200	-11,700	-11,900	-10,900	-40,842	-44,737	-46,726
Income before income tax expense	94,300	82,800	57,700	80,000	114,000	101,400	68,700	51,700	314,788	335,774	17,483
Income tax expense	29,600	13,700	15,200	23,500	35,800	30,100	14,000	12,700	82,024	92,578	74,416
Net income (loss)	64,700	69,100	42,500	56,500	78,200	71,300	54,700	39,000	232,764	243,196	-56,933
Noncontrolling interests in income of consolidated subsidiaries, net of tax	-600	100	-2,300	-100	-1,700	-500	-900	-900	-2,910	-3,953	-1,634
Net income (loss) attributable to AECOM	$64,100	$69,200	$40,200	$56,400	$76,500	$70,800	$53,800	$38,100	$229,854	$239,243	($58,567)
Net income (loss) attributable to AECOM per share:	'	'	'	'	'	'	'	'	'	'	'
Basic (in dollars per share)	$0.65	$0.71	$0.41	$0.59	$0.78	$0.71	$0.54	$0.36	$2.36	$2.38	($0.52)
Diluted (in dollars per share)	$0.64	$0.70	$0.41	$0.58	$0.77	$0.70	$0.53	$0.36	$2.33	$2.35	($0.52)
Weighted average shares outstanding:	'	'	'	'	'	'	'	'	'	'	'
Basic (in shares)	98,100	97,500	97,000	96,300	98,000	99,300	100,400	104,800	97,226	100,618	111,875
Diluted (in shares)	99,700	99,000	98,300	97,600	99,700	100,800	101,800	105,500	98,657	101,942	111,875

Subsequent_Event_Details

Subsequent Event (Details) (USD $)

12 Months Ended

0 Months Ended

0 Months Ended

12 Months Ended

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2012

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Sep. 30, 2014

Oct. 17, 2014

Oct. 17, 2014

Oct. 17, 2014

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Subsequent Event [Member]

Line of Credit [Member]

Revolving Credit Facility [Member]

Letter of Credit [Member]

URS Corporation

URS Corporation

Senior Notes [Member]

Senior Notes [Member]

Term Loan A Member

Term Loan B Member

Senior Notes 5.43% series A due July 2020 and senior discount notes 1.00% series B due July 2022

Senior Notes 5.43% series A due July 2020 and senior discount notes 1.00% series B due July 2022

Senior Notes 5.43% Series A Due July 2020

Senior Discount Notes 1.00% Series B due July 2022

URS Corporation

URS Corporation

Secured Debt [Member]

Secured Debt [Member]

Subsequent event

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of ownership acquired

'

'

'

'

'

'

'

100.00%

'

'

'

'

'

'

'

'

Consideration paid in cash

$70,200,000

$62,100,000

$14,500,000

'

'

'

$2,300,000,000

'

'

'

'

'

'

'

'

'

Consideration paid by issuing stock

'

14,300,000

900,000

'

'

'

1,600,000,000

'

'

'

'

'

'

'

'

'

Senior notes assumed in acquisition as part of consideration

18,300,000

5,600,000

'

'

'

'

1,000,000,000

'

'

'

'

'

'

'

'

'

Repayment of acquiree term loan as part of consideration

'

'

'

'

'

'

600,000,000

'

'

'

'

'

'

'

'

'

Repayment of acquiree line of credit as part of consideration

'

'

'

'

'

'

100,000,000

'

'

'

'

'

'

'

'

'

Percentage price of original principal amount of note at which note can be redeemed

'

'

'

'

'

'

'

'

101.00%

'

'

'

'

'

'

'

Amount of notes purchased

'

'

'

'

'

'

'

'

'

600,000,000

'

'

'

'

'

'

Borrowing capacity

'

'

'

'

1,050,000,000

500,000,000

'

'

'

'

1,925,000,000

760,000,000

'

'

'

'

Maximum increase in borrowing capacity

'

'

'

500,000,000

'

'

'

'

'

'

'

'

'

'

'

'

Repayment of indebtedness

1,998,882,000

2,156,399,000

1,550,996,000

'

'

'

'

'

'

'

'

'

300,000,000

'

'

'

Prepayment of accrued interest and prepayment penalty

'

'

'

'

'

'

'

'

'

'

'

'

'

$56,000,000

'

'

Interest rate (as a percent)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.43%

1.00%

Subsequent_Event_Details_2

Subsequent Event (Details 2) (Subsequent Event [Member], USD $)	0 Months Ended
	Oct. 06, 2014
Notes	'
Subsequent event	'
Maximum duration within which the registration statement relating to the registered exchange offer is required to be declared effective	'390 days
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	'30 days
Maximum duration within which the shelf registration statement relating to the resale of the Notes is required to be declared effective	'60 days
Percentage of increase in annual interest rate when the debt is in default	0.25%
Additional percentage of increase in annual interest rate for each subsequent 90-day period during which the default continues	0.25%
Period during which additional percentage of increase in annual interest rate continues when the debt is in default	'90 days
Maximum additional interest rate per year when the debt is in default	1.00%
The 2022 Notes	'
Subsequent event	'
Principal amount	800,000,000
Interest rate (as a percent)	5.75%
The 2022 Notes | Redemption period one	'
Subsequent event	'
Redemption period, end date	15-Oct-17
Percentage price of original principal amount of note, excluding required premium, at which note can be redeemed	100.00%
Percentage price of original principal amount of note at which note can be redeemed	105.75%
The 2022 Notes | Redemption period one | Maximum	'
Subsequent event	'
Percentage of principal amount that can be redeemed	35.00%
The 2024 Notes	'
Subsequent event	'
Principal amount	800,000,000
Interest rate (as a percent)	5.88%
The 2024 Notes | Redemption period two	'
Subsequent event	'
Redemption period, end date	15-Jul-24
Percentage price of original principal amount of note, excluding required premium, at which note can be redeemed	100.00%
The 2024 Notes | Redemption period three	'
Subsequent event	'
Redemption period, start date	15-Jul-24
Percentage price of original principal amount of note at which note can be redeemed	100.00%

Schedule_II_Valuation_and_Qual1

Schedule II: Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Allowance for Doubtful Accounts [Member]	'	'	'
Changes in valuation and qualifying accounts	'	'	'
Balance at Beginning of Year	$86.40	$112.80	$120.20
Additions Charged to Cost of Revenue	17.3	18.3	28.7
Deductions	-38.4	-45.5	-37.7
Other and Foreign Exchange Impact	6.8	0.8	1.6
Balance at the End of the Year	$72.10	$86.40	$112.80