Stockholders' Equity (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2012
Stockholders Equity Note [Line Items]
Preferred stock, shares authorized	2.0	2.0
Common Stock Repurchase Program
Stockholders Equity Note [Line Items]
Repurchase and retirement of common shares (in shares)	10.5	12.5	9.7
Repurchased shares of its common stock on the open market, average repurchase price per share	$ 40.43	$ 34.50	$ 33.71
Common Stock shares remained available for repurchase under repurchase plans	21.8