Restructuring and Related Costs - Restructuring and Related Liabilities (Details) - USD ($) $ in Millions		3 Months Ended
		Jan. 31, 2018		Jan. 31, 2017
Restructuring Reserve [Roll Forward]
Balance, beginning of period		$ 8.4
Costs recognized		14.3	[1]	$ 5.0
Payments		(6.7)
Non-cash charges		0.2
Balance, end of period		16.1
Employee Severance
Restructuring Reserve [Roll Forward]
Balance, beginning of period		2.7
Costs recognized	[1]	8.7
Payments		(3.3)
Non-cash charges		0.0
Balance, end of period		8.1
External Support Fees
Restructuring Reserve [Roll Forward]
Balance, beginning of period		2.5
Costs recognized	[1]	4.0
Payments		(2.5)
Non-cash charges		0.0
Balance, end of period		4.0
Lease Exit
Restructuring Reserve [Roll Forward]
Balance, beginning of period		2.8
Costs recognized	[1]	0.5
Payments		(0.3)
Non-cash charges		0.2
Balance, end of period		3.2
Other Project Fees
Restructuring Reserve [Roll Forward]
Balance, beginning of period		0.4
Costs recognized	[1]	1.0
Payments		(0.6)
Non-cash charges		0.0
Balance, end of period		$ 0.8

[1] We include these costs within corporate expenses.