Shareholders' Equity (Company's Common Share Repurchase And Issuance Activity) (Details) - $ / shares	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Increase (Decrease) in Treasury Stock
Treasury stock, beginning balance, Shares	24,163,402	21,866,069
Shares of common stock repurchased under share repurchase program		2,497,029
Shares of treasury stock reissued	(144,419)	(199,696)
Treasury stock, ending balance, Shares	24,018,983	24,163,402
Treasury stock, beginning balance, Weighted-average price per share	$ 44.59	$ 42.95
Shares of common stock repurchased under share repurchase programs, Weighted-average price per share		58.87
Treasury stock, ending balance, Weighted-average price per share	$ 44.59	$ 44.59