Revenue Recognition (Narrative) (Details) $ in Billions	Jan. 31, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 3.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-02-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 2.4
Performance obligation, expected timing of satisfaction	12 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation percentage	67.00%
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-02-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligation	$ 1.2
Performance obligation, expected timing of satisfaction	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation percentage	33.00%