Shareholders' Equity (Company's Common Share Repurchase And Issuance Activity) (Details) (USD $)	6 Months Ended
Jul. 31, 2014
Increase (Decrease) in Treasury Stock [Roll Forward]
Treasury stock, beginning balance, Shares	21,177,130
Treasury stock, beginning balance, Weighted-average price per share	$ 42.26
Shares of treasury stock reissued	(181,704)
Treasury stock, ending balance, Shares	20,995,426
Treasury stock, ending balance, Weighted-average price per share	$ 42.26

Number of shares held for each class of treasury stock.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Name:	us-gaap_TreasuryStockNumberOfSharesHeld
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant