Employee Benefits - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Other changes in plan assets and benefit obligations recognized in other comprehensive income:
Net loss (gain)	$ 20.8	$ 34.2	$ (9.3)
Amortizations of net (gain)	(4.0)	(0.8)	(1.7)
Total recognized in other comprehensive income	16.8	33.4	(11.0)
Total recognized in net periodic benefit cost and other comprehensive income	$ 29.0	$ 40.6	$ (2.8)