Restructuring and Related Costs - Cumulative Restructuring and Related Charges (Details) $ in Millions	Jan. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Cumulative charges	$ 78.4
GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	13.3
2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	65.1
External Support Fees
Restructuring Cost and Reserve [Line Items]
Cumulative charges	32.0
External Support Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	2.0
External Support Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	30.0
Employee Severance
Restructuring Cost and Reserve [Line Items]
Cumulative charges	24.2
Employee Severance | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	10.5
Employee Severance | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	13.7
Other Project Fees
Restructuring Cost and Reserve [Line Items]
Cumulative charges	11.4
Other Project Fees | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	0.8
Other Project Fees | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	10.6
Lease Exit
Restructuring Cost and Reserve [Line Items]
Cumulative charges	6.3
Lease Exit | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	0.0
Lease Exit | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	6.3
Asset Impairment
Restructuring Cost and Reserve [Line Items]
Cumulative charges	4.7
Asset Impairment | GCA Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	0.0
Asset Impairment | 2020 Vision Restructuring Program
Restructuring Cost and Reserve [Line Items]
Cumulative charges	$ 4.7