Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2019	Apr. 30, 2018	Apr. 30, 2019	Apr. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 122.4	$ 60.9	$ 225.5	$ (61.6)
Other comprehensive (loss) income:
Foreign currency translation adjustment, net of tax	(18.6)	(43.0)	14.1	59.3
Comprehensive income (loss)	$ 103.8	$ 17.9	$ 239.6	$ (2.3)