Employee Benefit Plans (Restricted Stock Units) - Additional Information (Detail) $ / shares in Units, $ in Millions		12 Months Ended
	Oct. 31, 2020 USD ($) $ / shares	Oct. 31, 2020 USD ($) $ / shares
Schedule Of Restricted Stock [Line Items]
Closing stock price (in USD per share) | $ / shares	$ 213.86	$ 213.86
Unamortized share-based compensation expense	$ 488.6	$ 488.6
Weighted-average period of total compensation costs to be recognized over a period in years		2 years 3 months 18 days
Restricted Stock Units
Schedule Of Restricted Stock [Line Items]
share reserve ratio	1.70
Restricted Stock Units | Minimum
Schedule Of Restricted Stock [Line Items]
Vesting period, (in years)		3 years
Restricted Stock Units | Maximum
Schedule Of Restricted Stock [Line Items]
Vesting period, (in years)		4 years
Employee Stock Purchase Plan
Schedule Of Restricted Stock [Line Items]
Unamortized share-based compensation expense	$ 55.8	$ 55.8
Weighted-average period of total compensation costs to be recognized over a period in years		2 years