Financial Derivatives and Hedging - Schedule of Changes in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance	$ 5,989.9	$ 3,730.9	$ 3,824.8	$ 3,628.6
Amount recognized in other comprehensive income on interest rate swaps contracts, net of tax			16.6
Amount reclassified from other comprehensive income into earnings, net of tax			3.1
Ending balance	6,162.8	$ 3,627.5	6,162.8	3,627.5
Accumulated Gain (Loss), Net, Cash Flow Hedge, Before Tax, Parent
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance			(17.1)
Ending balance	8.9		8.9
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
AOCI Attributable To Parent, Before Reclassification And Tax [Roll Forward]
Beginning balance			(13.0)	$ 0.0
Amount recognized in other comprehensive income on interest rate swap contracts, gross ($16.6 million, net of tax)			21.9
Amount reclassified from other comprehensive income into earnings, gross ($3.1 million, net of tax)			4.1
Ending balance	$ 6.7		$ 6.7