Restructuring and Related Costs - Restructuring and Related Liabilities (Details) - USD ($) $ in Millions		12 Months Ended
		Oct. 31, 2018		Oct. 31, 2017	Oct. 31, 2016		Oct. 31, 2015
Restructuring Reserve [Roll Forward]
Balance, beginning		$ 8.4		$ 8.0	$ 6.6		$ 0.0
Costs recognized		25.7	[1]	20.9	29.0	[1]	12.7	[1]
Costs recognized	[1]			22.6
Payments		(24.7)		(23.0)	(25.2)		(3.3)
Non-cash charges		(0.7)			(2.5)		(2.8)
Non-cash charges				0.9
Balance, ending		8.6		8.4	8.0		6.6
External Support Fees
Restructuring Reserve [Roll Forward]
Balance, beginning		2.5		1.2	2.1		0.0
Costs recognized	[1]	4.0			11.3		4.6
Costs recognized	[1]			12.1
Payments		(6.5)		(10.8)	(12.2)		(2.5)
Non-cash charges		0.0			0.0		0.0
Non-cash charges				0.0
Balance, ending		0.0		2.5	1.2		2.1
Employee Severance
Restructuring Reserve [Roll Forward]
Balance, beginning		2.7		3.8	4.3		0.0
Costs recognized	[1]	11.0			8.6		4.7
Costs recognized	[1]			2.2
Payments		(9.9)		(3.3)	(9.1)		(0.4)
Non-cash charges		0.0			0.0		0.0
Non-cash charges				0.0
Balance, ending		3.8		2.7	3.8		4.3
Other Project Fees
Restructuring Reserve [Roll Forward]
Balance, beginning		0.4		0.5	0.2		0.0
Costs recognized	[1]	8.2			3.9		0.8
Costs recognized	[1]			5.7
Payments		(6.7)		(5.8)	(3.6)		(0.4)
Non-cash charges		0.0			0.0		(0.2)
Non-cash charges				0.0
Balance, ending		1.8		0.4	0.5		0.2
Lease Exit
Restructuring Reserve [Roll Forward]
Balance, beginning		2.8		2.5	0.0		0.0
Costs recognized	[1]	2.0			3.2		0.0
Costs recognized	[1]			2.6
Payments		(1.5)		(3.1)	(0.3)		0.0
Non-cash charges		(0.2)			(0.4)		0.0
Non-cash charges				0.9
Balance, ending		3.1		2.8	2.5		0.0
Asset Impairment
Restructuring Reserve [Roll Forward]
Balance, beginning		0.0		0.0	0.0		0.0
Costs recognized	[1]	0.6			2.1		2.6
Costs recognized	[1]			0.0
Payments		0.0		0.0	0.0		0.0
Non-cash charges		(0.6)			(2.1)		(2.6)
Non-cash charges				0.0
Balance, ending		$ 0.0		$ 0.0	$ 0.0		$ 0.0

[1] We include these costs within corporate expenses.