Lines of Credit (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Line of Credit Facility [Line Items]
Used lines of credit	$ 49.0		$ 34.5
Unused lines of credit	991.3		1,028.7
Total available lines of credit	1,040.3		1,063.2
Total available lines of credit	1,040.3		1,063.2
Accounts receivable securitization program-committed	118.0	[1]	92.0	[1]
Committed line of credit facilities [Member]
Line of Credit Facility [Line Items]
Total available lines of credit	703.1		703.9
Total available lines of credit	703.1		703.9
Uncommitted line of credit facilities [Member]
Line of Credit Facility [Line Items]
Total available lines of credit	337.3		359.3
Total available lines of credit	$ 337.3		$ 359.3

[1] See Note 9, "Accounts Receivable Securitization Program," for further details of this program.