Off-Balance Sheet Risk and Guarantees and Concentrations of Credit Risk (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Off Balance Sheet Risk and Guarantees, Concentrations of Credit Risk and Fair Value of Financial Instruments [Abstract]
Contingently liable for bank guarantees and standby letters of credit issued on the company's behalf	$ 940.7
Liability to financial institutions for financial letters of credit and other guarantees issued on the Company's behalf	27.3
Liability for insurance bonds issued on the company's behalf	$ 13.9
Concentration risk customer revenue percentage maximum (in hundredths)	10.00%	10.00%	12.00%

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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

-Publisher FASB

-Name FASB Interpretation (FIN)

-Number 45

-Paragraph 13

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 460

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph (b)(1)

-URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12069-110248

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant