Share Repurchases (Schedule Of Company's Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended	12 Months Ended
	Oct. 31, 2015	Jan. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Total number of shares repurchased	23.2	13.4
Average price paid per share	$ 74.20	$ 75.82
Total amount paid for share repurchases	$ 1,720	$ 1,015