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Stockholders' (Deficit) Equity (Details) - $ / shares
12 Months Ended
Jan. 31, 2018
Jan. 31, 2017
Jan. 31, 2016
Stockholders Equity Note [Line Items]      
Preferred stock, shares authorized (in shares) 2,000,000.0 2,000,000.0  
Preferred stock, shares issued (in shares) 0 0  
Preferred stock, shares outstanding (in shares) 0 0  
Common Stock Repurchase Program      
Stockholders Equity Note [Line Items]      
Repurchase and retirement of common shares (in shares) 6,900,000 9,700,000 8,500,000
Average repurchase price per share (usd per share) $ 100.45 $ 64.73 $ 53.58
Common stock shares remained available for repurchase under repurchase plans (in shares) 19,600,000