Share Repurchases (Schedule Of Company's Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015
Equity, Class of Treasury Stock [Line Items]
Total number of shares repurchased	90.6	23.2
Average price paid per share	$ 69.04	$ 74.20
Total amount paid for share repurchases	$ 6,254	$ 1,720