Revenue - Performance Obligations (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jul. 31, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-02-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue			$ 65
Expected revenue, period			9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-11-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue			$ 81
Expected revenue, period			1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-11-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue			$ 66
Expected revenue, period			1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-11-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue			$ 37
Expected revenue, period			1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-11-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected revenue			$ 16
Expected revenue, period			1 year
Extended Warranty Programs [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue from Contract with Customer, Including Assessed Tax	$ 25	$ 29