Shareholders' Equity (Company's Common Share Repurchase And Issuance Activity) (Details) (USD $)	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011
Shareholders' Equity [Abstract]
Treasury stock, beginning balance, Shares	12,517,538	7,776,419
Treasury stock, beginning balance, Weighted-average price per share	$ 37.28	$ 35.90
Shares of common stock repurchased under share repurchase programs, Shares	6,736,436	5,084,770
Shares of common stock repurchased under share repurchase programs, Weighted-average price per share	$ 46.74	$ 39.33
Shares of treasury stock reissued	(1,087,213)	(343,651)
Treasury stock, ending balance, Shares	18,166,761	12,517,538
Treasury stock, ending balance, Weighted-average price per share	$ 40.71	$ 37.28