Employee Benefits - Schedule of Components of Net Periodic Defined Benefit Costs (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020
Retirement Benefits [Abstract]
Service cost	$ 4.3	$ 3.4	$ 8.6	$ 6.9
Interest cost	1.1	1.4	2.2	2.6
Expected return on plan assets	(3.1)	(2.7)	(6.2)	(5.4)
Recognized net actuarial loss	1.3	1.0	2.7	2.0
Net periodic defined benefit plan cost	$ 3.6	$ 3.1	$ 7.3	$ 6.1