Taxes on Earnings - Deferred Tax Asset Valuation Allowance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Valuation Allowance [Line Items]
Valuation allowance for deferred tax assets	$ 7,930	$ 7,906	$ 8,807	$ 8,520
(Decrease) increase in valuation allowances	24	901	287
Deferred tax asset valuation allowance
Valuation Allowance [Line Items]
Valuation allowance for deferred tax assets	$ 7,900	$ 7,900	$ 8,800