Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2021	Apr. 30, 2020
Revenue from External Customer [Line Items]
Revenues	$ 1,497.4	$ 1,496.0	$ 2,989.8	$ 3,109.0
Operating Segments
Revenue from External Customer [Line Items]
Revenues	1,530.5	1,526.4	3,055.0	3,170.0
Operating Segments | Business & Industry
Revenue from External Customer [Line Items]
Revenues	796.2	785.6	1,605.6	1,606.5
Operating Segments | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	246.3	233.7	495.5	467.6
Operating Segments | Education
Revenue from External Customer [Line Items]
Revenues	214.2	200.1	423.6	408.0
Operating Segments | Aviation
Revenue from External Customer [Line Items]
Revenues	148.3	184.7	291.5	423.5
Operating Segments | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	125.5	122.3	238.8	264.3
Operating Segments | Janitorial
Revenue from External Customer [Line Items]
Revenues	1,058.4	996.7	2,116.1	1,996.9
Operating Segments | Janitorial | Business & Industry
Revenue from External Customer [Line Items]
Revenues	644.4	597.0	1,291.3	1,190.5
Operating Segments | Janitorial | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	197.3	190.3	394.2	376.0
Operating Segments | Janitorial | Education
Revenue from External Customer [Line Items]
Revenues	187.6	177.5	372.4	363.7
Operating Segments | Janitorial | Aviation
Revenue from External Customer [Line Items]
Revenues	29.1	31.9	58.2	66.7
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	140.5	176.4	276.7	396.1
Operating Segments | Parking | Business & Industry
Revenue from External Customer [Line Items]
Revenues	68.3	97.1	137.3	222.9
Operating Segments | Parking | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	10.0	7.4	21.7	15.5
Operating Segments | Parking | Education
Revenue from External Customer [Line Items]
Revenues	0.2	0.6	0.4	1.4
Operating Segments | Parking | Aviation
Revenue from External Customer [Line Items]
Revenues	61.9	71.3	117.3	156.3
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	155.5	157.1	320.9	330.3
Operating Segments | Facility Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues	83.4	91.3	176.8	192.8
Operating Segments | Facility Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	39.0	35.9	79.6	76.1
Operating Segments | Facility Services | Education
Revenue from External Customer [Line Items]
Revenues	26.3	22.0	50.8	43.0
Operating Segments | Facility Services | Aviation
Revenue from External Customer [Line Items]
Revenues	6.8	7.9	13.7	18.5
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	125.5	122.3	238.8	264.3
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 | Education
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 | Technical Solutions
Revenue from External Customer [Line Items]
Revenues	125.5	122.3	238.8	264.3
Operating Segments | Airline Services
Revenue from External Customer [Line Items]
Revenues	50.6	73.8	102.5	182.3
Operating Segments | Airline Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues	0.1	0.1	0.2	0.3
Operating Segments | Airline Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Airline Services | Education
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Segments | Airline Services | Aviation
Revenue from External Customer [Line Items]
Revenues	50.5	73.7	102.2	182.0
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	$ (33.1)	$ (30.4)	$ (65.2)	$ (61.0)