Debt (Other Credit Facilities) (Narrative) (Details) (USD $)	6 Months Ended
	Jul. 31, 2011	Jan. 31, 2011
Maximum borrowing capacity	$ 1,000,000,000
U.S. trade receivables	2,833,724,000	2,896,671,000
Line of credit, outstanding amount	77,600,000
Minimum [Member] | Multi-Currency Revolving Credit Facility [Member]
Period of interest rate (days)	7
Maximum [Member] | Multi-Currency Revolving Credit Facility [Member]
Period of interest rate (days)	180
Standby Letters Of Credit [Member]
Standby letters of credit issued	81,400,000
Receivables Securitization Program [Member]
Maximum borrowing capacity	300,000,000
U.S. trade receivables	636,600,000	549,800,000
Commitment fee per annum	0.35%
Line of credit, outstanding amount	0	0
Multi-Currency Revolving Credit Facility [Member]
Maximum borrowing capacity	250,000,000
Commitment fee per annum	0.125%
Line of credit, outstanding amount	0	0
Revolving credit loans, expiration date	March 2012
Other Committed And Uncommitted Revolving Credit Facilities, Expiring On Various Dates Through Fiscal 2012 [Member]
Maximum borrowing capacity	$ 604,000,000