Revenue - Performance Obligations (Details) $ in Millions	Apr. 30, 2020 USD ($)
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-05-01
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 45
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue, period	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-11-01
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 86
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-11-01
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 64
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-11-01
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 36
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-11-01
Revenue from Contract with Customer [Abstract]
Expected revenue	$ 16
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue, period	1 year