Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2019	Jan. 31, 2018	Oct. 31, 2018
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0	$ 5
Current restructuring liability reported in Accrued restructuring	239		$ 294
Non-current restructuring liability reported in Other liabilities	26		31
All Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Current restructuring liability reported in Accrued restructuring	$ 46		$ 53