Stockholders' Equity - Share Repurchases (Details) - USD ($)	3 Months Ended		9 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Jul. 31, 2020	Jul. 31, 2019	Mar. 31, 2017	Dec. 31, 2011
Stockholders' Equity Note [Abstract]
Share repurchase program, authorized amount for repurchase					$ 1,000,000,000.0	$ 500,000,000.0
Share repurchase program, remaining authorized amount for repurchase	$ 359,700,000		$ 359,700,000
Treasury stock repurchase (in shares)	0	0	160,850	24,500