Stockholders' Equity - Additional Information (Details) - Common Stock Repurchase Program - $ / shares shares in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Class of Stock [Line Items]
Common stock repurchased and retired (in shares)	0.2	0.1	0.7	1.3
Repurchased shares of its common stock on the open market, average repurchase price per share (in usd per share)	$ 282.67	$ 216.84	$ 278.34	$ 155.20
Common stock shares remained available for repurchase under repurchase plans (in shares)	11.4	13.5	11.4	13.5