Employee Benefits - Components of Net Periodic Pension Costs and Other Amounts Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Retirement Benefits [Abstract]
Service cost	$ 13.9	$ 10.1	$ 10.7
Interest cost	5.2	6.1	5.0
Expected return on plan assets	(10.8)	(9.8)	(9.2)
Recognized actuarial loss	4.0	0.8	1.7
Net periodic pension cost	$ 12.3	$ 7.2	$ 8.2