Share Repurchases (Schedule Of Company's Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Total number of shares repurchased	17.1	12.3
Average price paid per share	$ 75.27	$ 75.96
Total amount paid for share repurchases	$ 1,283	$ 933