Restructuring and Related Costs - Cumulative Restructuring and Related Charges (Details) $ in Millions	Oct. 31, 2019 USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	$ 101.1
GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	34.6
2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	66.5
External Support Fees
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	33.5
External Support Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	3.5
External Support Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	30.0
Employee Severance
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	31.0
Employee Severance | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	18.0
Employee Severance | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	13.0
Other Project Fees
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	23.0
Other Project Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	12.3
Other Project Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	10.7
Lease Exit
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	8.4
Lease Exit | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	0.7
Lease Exit | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	7.7
Asset Impairment
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	5.2
Asset Impairment | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	0.0
Asset Impairment | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, cumulative cost	$ 5.2