Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Revenue from External Customer [Line Items]
Revenues	$ 1,496.0	$ 1,594.7	$ 3,109.0	$ 3,202.6
Operating Segments
Revenue from External Customer [Line Items]
Revenues	1,526.4	1,627.3	3,170.0	3,269.6
Operating Segments | Business & Industry
Revenue from External Customer [Line Items]
Revenues	785.6	807.7	1,606.5	1,636.6
Operating Segments | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	233.7	224.3	467.6	460.4
Operating Segments | Aviation
Revenue from External Customer [Line Items]
Revenues	184.7	250.0	423.5	502.4
Operating Segments | Education
Revenue from External Customer [Line Items]
Revenues	200.1	209.3	408.0	418.2
Operating Segments | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	122.3	135.9	264.3	252.0
Operating Segments | Janitorial
Revenue from External Customer [Line Items]
Revenues	996.7	979.1	1,996.9	1,969.6
Operating Segments | Janitorial | Business & Industry
Revenue from External Customer [Line Items]
Revenues	597.0	576.3	1,190.5	1,160.2
Operating Segments | Janitorial | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	190.3	183.8	376.0	371.0
Operating Segments | Janitorial | Aviation
Revenue from External Customer [Line Items]
Revenues	31.9	31.1	66.7	63.0
Operating Segments | Janitorial | Education
Revenue from External Customer [Line Items]
Revenues	177.5	187.9	363.7	375.4
Operating Segments | Janitorial | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Parking
Revenue from External Customer [Line Items]
Revenues	176.4	216.7	396.1	438.8
Operating Segments | Parking | Business & Industry
Revenue from External Customer [Line Items]
Revenues	97.1	125.7	222.9	253.8
Operating Segments | Parking | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	7.4	5.9	15.5	13.3
Operating Segments | Parking | Aviation
Revenue from External Customer [Line Items]
Revenues	71.3	84.3	156.3	170.1
Operating Segments | Parking | Education
Revenue from External Customer [Line Items]
Revenues	0.6	0.8	1.4	1.6
Operating Segments | Parking | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Facility Services
Revenue from External Customer [Line Items]
Revenues	157.1	177.4	330.3	372.7
Operating Segments | Facility Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues	91.3	105.6	192.8	222.2
Operating Segments | Facility Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	35.9	34.6	76.1	76.0
Operating Segments | Facility Services | Aviation
Revenue from External Customer [Line Items]
Revenues	7.9	16.6	18.5	33.3
Operating Segments | Facility Services | Education
Revenue from External Customer [Line Items]
Revenues	22.0	20.6	43.0	41.3
Operating Segments | Facility Services | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	122.3	135.9	264.3	252.0
Operating Segments | Building & Energy Solutions | Business & Industry
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Building & Energy Solutions | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Building & Energy Solutions | Aviation
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Building & Energy Solutions | Education
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Building & Energy Solutions | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	122.3	135.9	264.3	252.0
Operating Segments | Airline Services
Revenue from External Customer [Line Items]
Revenues	73.8	118.2	182.3	236.5
Operating Segments | Airline Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues	0.1	0.2	0.3	0.4
Operating Segments | Airline Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.1
Operating Segments | Airline Services | Aviation
Revenue from External Customer [Line Items]
Revenues	73.7	118.0	182.0	236.1
Operating Segments | Airline Services | Education
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Airline Services | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Intersegment Eliminations
Revenue from External Customer [Line Items]
Revenues	$ (30.4)	$ (32.6)	$ (61.0)	$ (67.0)