REVENUES - Schedule of Disaggregation of Revenues (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2025	Jul. 31, 2024	Jul. 31, 2025	Jul. 31, 2024
Revenue from External Customer [Line Items]
Revenues	$ 2,224.0	$ 2,094.2	$ 6,450.5	$ 6,182.0
Facility Solutions
Revenue from External Customer [Line Items]
Revenues	1,667.8	1,599.4	4,873.4	4,753.5
Janitorial
Revenue from External Customer [Line Items]
Revenues	1,323.8	1,277.0	3,896.1	3,814.8
Aviation Services
Revenue from External Customer [Line Items]
Revenues	134.5	118.8	368.2	341.2
Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	209.4	203.6	609.1	597.5
Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	556.2	494.8	1,577.1	1,428.5
Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	304.8	285.1	910.4	876.6
Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	251.4	209.7	666.8	551.9
B&I
Revenue from External Customer [Line Items]
Revenues	1,038.7	1,010.6	3,077.2	3,033.4
B&I \| Facility Solutions
Revenue from External Customer [Line Items]
Revenues	827.1	802.1	2,441.3	2,382.5
B&I \| Janitorial
Revenue from External Customer [Line Items]
Revenues	715.5	696.1	2,119.9	2,070.7
B&I \| Aviation Services
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
B&I \| Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	111.6	106.0	321.4	311.8
B&I \| Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	211.7	208.5	635.9	650.8
B&I \| Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	210.5	208.5	632.0	650.8
B&I \| Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	1.2	0.0	3.9	0.0
M&D
Revenue from External Customer [Line Items]
Revenues	408.9	377.1	1,201.2	1,166.6
M&D \| Facility Solutions
Revenue from External Customer [Line Items]
Revenues	356.9	339.3	1,049.8	1,051.5
M&D \| Janitorial
Revenue from External Customer [Line Items]
Revenues	343.3	326.5	1,010.9	1,013.5
M&D \| Aviation Services
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
M&D \| Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	13.6	12.8	38.9	38.0
M&D \| Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	52.0	37.8	151.4	115.1
M&D \| Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	51.3	37.8	150.5	115.1
M&D \| Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	0.7	0.0	0.9	0.0
Aviation
Revenue from External Customer [Line Items]
Revenues	291.8	268.4	822.0	756.1
Aviation \| Facility Solutions
Revenue from External Customer [Line Items]
Revenues	278.8	257.2	782.7	720.8
Aviation \| Janitorial
Revenue from External Customer [Line Items]
Revenues	60.1	53.7	166.0	132.1
Aviation \| Aviation Services
Revenue from External Customer [Line Items]
Revenues	134.5	118.8	368.2	341.2
Aviation \| Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	84.2	84.6	248.4	247.5
Aviation \| Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	12.9	11.2	39.3	35.3
Aviation \| Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	12.9	11.2	39.3	35.3
Aviation \| Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Education
Revenue from External Customer [Line Items]
Revenues	235.1	228.3	688.2	674.0
Education \| Facility Solutions
Revenue from External Customer [Line Items]
Revenues	205.0	200.7	599.6	598.7
Education \| Janitorial
Revenue from External Customer [Line Items]
Revenues	204.9	200.6	599.3	598.4
Education \| Aviation Services
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Education \| Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	0.1	0.1	0.3	0.3
Education \| Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	30.1	27.6	88.6	75.4
Education \| Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	30.1	27.6	88.6	75.4
Education \| Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions
Revenue from External Customer [Line Items]
Revenues	249.5	209.7	662.0	551.9
Technical Solutions \| Facility Solutions
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions \| Janitorial
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions \| Aviation Services
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions \| Parking and Transportation
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions \| Engineering and Infrastructure Solutions
Revenue from External Customer [Line Items]
Revenues	249.5	209.7	662.0	551.9
Technical Solutions \| Operations and Maintenance
Revenue from External Customer [Line Items]
Revenues	0.0	0.0	0.0	0.0
Technical Solutions \| Building & Energy Solutions
Revenue from External Customer [Line Items]
Revenues	$ 249.5	$ 209.7	$ 662.0	$ 551.9