Employee Benefits - Changes in Benefit Obligation, Changes in Plan Assets and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Change in benefit obligation
Benefit obligation, beginning of year	$ 189.7	$ 147.1	$ 151.7
Service cost	13.9	10.1	10.7
Interest cost	5.2	6.1	5.0
Benefits paid	(10.0)	(10.2)	(3.7)
Actuarial loss (gain)	20.0	36.6	(16.6)
Benefit obligation, end of year	218.8	189.7	147.1
Change in plan assets
Fair value of plan assets, beginning of year	136.0	121.0	112.8
Actual return on plan assets	10.1	12.1	1.9
Employer contributions	23.4	13.1	10.0
Benefits paid	(10.0)	(10.2)	(3.7)
Fair value of plan assets, end of year	159.5	136.0	121.0
Funded status at end of year	$ (59.3)	$ (53.7)	$ (26.1)