Commitments and Contingencies (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
Jun. 30, 2012
Commitments and Contingencies (Textual) [Abstract]
Commitments and Contingencies, additional bonding capacity	$ 377.3
Commitments and Contingencies, facility agreement	11.7
Secured and Unsecured Letter of Credit [Member]
Commitments and Contingencies (Additional Textual) [Abstract]
Loss contingency, estimate of possible loss	41.1
Performance and Maintenance Bonds [Member]
Commitments and Contingencies (Additional Textual) [Abstract]
Loss contingency, estimate of possible loss	222.7
Guarantee Obligations [Member]
Commitments and Contingencies (Additional Textual) [Abstract]
Loss contingency, estimate of possible loss	$ 8.5

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14557-108349

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant