Revenues - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Revenue from External Customer [Line Items]
Revenues	$ 1,648.0	$ 1,647.9	$ 1,594.7	$ 1,607.9	$ 1,648.8	$ 1,624.3	$ 1,580.8	$ 1,588.3	$ 6,498.6	$ 6,442.2	$ 5,453.6
Operating Segments
Revenue from External Customer [Line Items]
Revenues									6,626.3
Operating Segments | Business & Industry
Revenue from External Customer [Line Items]
Revenues									3,251.4	3,268.4	2,939.4
Operating Segments | Aviation
Revenue from External Customer [Line Items]
Revenues									1,017.3	1,038.7	1,003.0
Operating Segments | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									917.0	925.4	698.1
Operating Segments | Education
Revenue from External Customer [Line Items]
Revenues									847.4	856.7	368.8
Operating Segments | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									593.2	$ 500.1	$ 473.4
Operating Segments | Janitorial
Revenue from External Customer [Line Items]
Revenues									3,937.9
Operating Segments | Janitorial | Business & Industry
Revenue from External Customer [Line Items]
Revenues									2,316.1
Operating Segments | Janitorial | Aviation
Revenue from External Customer [Line Items]
Revenues									125.8
Operating Segments | Janitorial | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									739.7
Operating Segments | Janitorial | Education
Revenue from External Customer [Line Items]
Revenues									756.3
Operating Segments | Janitorial | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Parking
Revenue from External Customer [Line Items]
Revenues									875.8
Operating Segments | Parking | Business & Industry
Revenue from External Customer [Line Items]
Revenues									511.5
Operating Segments | Parking | Aviation
Revenue from External Customer [Line Items]
Revenues									335.3
Operating Segments | Parking | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									25.9
Operating Segments | Parking | Education
Revenue from External Customer [Line Items]
Revenues									3.1
Operating Segments | Parking | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Facility Services
Revenue from External Customer [Line Items]
Revenues									734.6
Operating Segments | Facility Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues									423.1
Operating Segments | Facility Services | Aviation
Revenue from External Customer [Line Items]
Revenues									72.1
Operating Segments | Facility Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									151.4
Operating Segments | Facility Services | Education
Revenue from External Customer [Line Items]
Revenues									88.0
Operating Segments | Facility Services | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues									593.2
Operating Segments | Building & Energy Solutions | Business & Industry
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Building & Energy Solutions | Aviation
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Building & Energy Solutions | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Building & Energy Solutions | Education
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Building & Energy Solutions | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									593.2
Operating Segments | Airline Services
Revenue from External Customer [Line Items]
Revenues									484.8
Operating Segments | Airline Services | Business & Industry
Revenue from External Customer [Line Items]
Revenues									0.6
Operating Segments | Airline Services | Aviation
Revenue from External Customer [Line Items]
Revenues									484.1
Operating Segments | Airline Services | Technology & Manufacturing
Revenue from External Customer [Line Items]
Revenues									0.1
Operating Segments | Airline Services | Education
Revenue from External Customer [Line Items]
Revenues									0.0
Operating Segments | Airline Services | Technical Solutions
Revenue from External Customer [Line Items]
Revenues									0.0
Intersegment Eliminations
Revenue from External Customer [Line Items]
Revenues									$ (127.7)