Revenue Recognition (Narrative) (Details) $ in Millions	9 Months Ended
	Oct. 31, 2019 USD ($) categories
Revenue from Contract with Customer [Abstract]
Number of revenue categories | categories	3
Contract with customer, liability, revenue recognized	$ 1,580.0
Remaining performance obligation	2,970.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-11-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 2,050.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation percentage	69.00%
Performance obligation, expected timing of satisfaction	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-11-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 918.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation percentage	31.00%
Performance obligation, expected timing of satisfaction	3 years