Debt and Credit Facilities - Lines of Credit (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Line Of Credit Facility [Line Items]
Used lines of credit	$ 75.2	$ 39.2
Unused lines of credit	1,003.4	989.5
Total available lines of credit	1,078.6	1,028.7
Accounts receivable securitization program - committed	200.0	112.0
Committed Line of Credit Facilities
Line Of Credit Facility [Line Items]
Total available lines of credit	700.5	700.5
Uncommitted Line of Credit Facilities
Line Of Credit Facility [Line Items]
Total available lines of credit	$ 378.1	$ 328.2