Goodwill and Other Intangible Assets - Changes in Carrying Amounts of Goodwill by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Goodwill [Roll Forward]
Beginning balance	$ 1,835.4	$ 1,834.8
Reallocation		0.0
Foreign currency translation	(0.2)	0.6
Impairment loss	(163.8)
Ending balance	1,671.4	1,835.4
Business & Industry
Goodwill [Roll Forward]
Beginning balance	573.9	527.9
Reallocation		45.7
Foreign currency translation	0.1	0.3
Impairment loss	0.0
Ending balance	574.0	573.9
Technology & Manufacturing
Goodwill [Roll Forward]
Beginning balance	407.2	407.2
Reallocation		0.0
Foreign currency translation	0.0	0.0
Impairment loss	0.0
Ending balance	407.2	407.2
Education
Goodwill [Roll Forward]
Beginning balance	558.6	557.4
Reallocation		1.2
Foreign currency translation	0.0	0.0
Impairment loss	(99.3)
Ending balance	459.3	558.6
Aviation
Goodwill [Roll Forward]
Beginning balance	125.0	124.9
Reallocation		0.0
Foreign currency translation	0.0	0.1
Impairment loss	(55.5)
Ending balance	69.5	125.0
Technical Solutions
Goodwill [Roll Forward]
Beginning balance	170.7	158.7
Reallocation		11.8
Foreign currency translation	(0.3)	0.3
Impairment loss	(9.0)
Ending balance	161.5	170.7
Healthcare
Goodwill [Roll Forward]
Beginning balance	0.0	58.7
Reallocation		(58.7)
Foreign currency translation	0.0	0.0
Impairment loss
Ending balance	$ 0.0	$ 0.0