Stockholders' Equity (Details) - $ / shares	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Stockholders Equity Note [Line Items]
Preferred stock, shares authorized	2,000,000.0	2,000,000.0
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common Stock Repurchase Program
Stockholders Equity Note [Line Items]
Repurchase and retirement of common shares (in shares)	8,500,000	6,900,000	10,500,000
Average repurchase price per share (usd per share)	$ 53.58	$ 53.83	$ 40.43
Common Stock shares remained available for repurchase under repurchase plans	6,300,000