Restructuring - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Oct. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 3	$ 83
Current restructuring liability reported in Accrued restructuring	412		$ 445
Non-current restructuring liability reported in Other liabilities	72		96
All Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Restructuring charges	3
Current restructuring liability reported in Accrued restructuring	$ 75		$ 158