Shareholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Apr. 30, 2017	May 01, 2016
Notes to financial statements [Abstract]
Aggregated number of shares repurchased under stock repurchase program	245
Aggregated cost of shares repurchased	$ 4,590
Stock Repurchase Program, Remaining Authorized Repurchase Amount	2,730
Payments of Dividends	$ 82	$ 62
Cash dividends declared and paid per common share	$ 0.140	$ 0.115
Authorized number of shares of common stock	2,000
Par value of common stock	$ 0.001