Segment Information - Financial Information by Reportable Segment (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2021	Jan. 31, 2020
Revenues
Revenues	$ 1,492.4	$ 1,612.9
Operating profit (loss)
Operating profit (loss)	109.7	45.8
Income from unconsolidated affiliates	0.6	0.9
Interest expense	(8.5)	(10.2)
Income from continuing operations before income taxes	101.9	36.5
Operating Segments
Revenues
Revenues	1,524.5	1,643.6
Elimination of inter-segment revenues
Revenues
Revenues	(32.1)	(30.6)
Corporate
Operating profit (loss)
Operating profit (loss)	(32.6)	(33.3)
Segment Reconciling Items
Operating profit (loss)
Income from unconsolidated affiliates	(0.6)	(0.9)
Adjustment for tax deductions for energy efficient government buildings, included in Technical Solutions	(0.2)	0.0
Business & Industry | Operating Segments
Revenues
Revenues	809.4	820.9
Operating profit (loss)
Operating profit (loss)	85.7	38.2
Technology & Manufacturing | Operating Segments
Revenues
Revenues	249.2	233.9
Operating profit (loss)
Operating profit (loss)	26.9	16.7
Education | Operating Segments
Revenues
Revenues	209.4	208.0
Operating profit (loss)
Operating profit (loss)	21.5	11.2
Aviation | Operating Segments
Revenues
Revenues	143.1	238.7
Operating profit (loss)
Operating profit (loss)	3.2	5.6
Technical Solutions | Operating Segments
Revenues
Revenues	113.4	142.0
Operating profit (loss)
Operating profit (loss)	6.0	8.3
Government Services | Operating Segments
Operating profit (loss)
Operating profit (loss)	$ (0.1)	$ 0.0