Stockholders' (Deficit) Equity (Details) - $ / shares	12 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
Class of Stock [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
Class of Stock [Line Items]
Repurchase and retirement of common shares (in shares)	2,200,000	6,900,000	9,700,000
Average repurchase price per share (in dollars per share)	$ 130.15	$ 100.45	$ 64.73
Common stock shares remained available for repurchase under repurchase plans (in shares)	17,400,000