Stockholders' Equity - Additions to and Reclassifications out of Accumulated Other Comprehensive (Loss) Earnings (Details) - USD ($) $ in Millions		3 Months Ended
		Apr. 30, 2020	Apr. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), net of tax		$ (18.5)	$ (13.2)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax gain (loss) recognized in OCI		(29.2)	(21.8)
Income tax (benefit) expense		1.1	(2.4)
Other comprehensive income (loss), net of tax		(28.1)	(24.2)
Deferred hedging gain (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pre-tax gain (loss) recognized in OCI		8.3	17.7
Income tax (benefit) expense		1.6	(1.3)
Reclassification from accumulated other comprehensive income, before tax	[1]	(1.4)	(7.6)
Other comprehensive income (loss), net of tax		5.3	8.8
Net unrealized loss on benefit plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, before tax	[2]	5.7	2.8
Amortization of prior service credit
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification from accumulated other comprehensive income, before tax	[2]	(0.1)	(0.2)
Accumulated defined benefit plans adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Income tax (benefit) expense		(1.3)	(0.4)
Other comprehensive income (loss), net of tax		$ 4.3	$ 2.2

[1] These gains are reclassified into Cost of sales, Interest expense and financing costs and Other income, net (see "Note 9. Hedging Instruments" for additional details).

[2] These losses (gains) are included in the computation of net periodic benefit cost (see "Note 14. Employee Benefit Plans" for additional details) and are reclassified into Other income, net.