Acquisitions - Total Purchase Consideration for Business and Asset Acquisitions (Details) - USD ($) $ in Millions	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Goodwill	$ 2,447.3	$ 2,428.9	$ 2,392.1
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	20.4	30.1	1,189.6
Goodwill	15.3	29.8	70.6
Net tangible (liabilities) assets	(0.3)	7.3	59.6
Total purchase price	35.4	67.2	1,319.8
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions | Customer relationships
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	11.4	7.5	23.5
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions | Trademarks
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	5.1	10.2	100.0
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions | Technology
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	0.0	12.3	0.0
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions | Composite intangible asset
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	0.0	0.0	1,061.9
Series Of Individually Immaterial Business Acquisitions And Asset Acquisitions | Other
Schedule Of Business Acquisitions And Asset Acquisition, By Acquisition [Line Items]
Total identifiable intangible assets	$ 3.9	$ 0.1	$ 4.2