Stockholders' Equity - Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended				6 Months Ended
	Apr. 30, 2022	Jan. 31, 2022	Apr. 30, 2021	Jan. 31, 2021	Apr. 30, 2022	Apr. 30, 2021	Mar. 31, 2017	Dec. 31, 2011
Stockholders' Equity Note [Abstract]
Share repurchase program, authorized amount for repurchase							$ 1,000.0	$ 500.0
Treasury stock repurchase (in shares)	0		0		191,200	69,600
Treasury stock repurchase	$ 0.0	$ 78.5	$ 0.0	$ 24.8	$ 78.5	$ 24.8
Average repurchase price per share (in dollars per share)					$ 410.41	$ 356.61
Share repurchase program, remaining authorized amount for repurchase	$ 256.4				$ 256.4