Taxes on Earnings - Deferred Tax Asset Valuation Allowance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Valuation Allowance [Line Items]
Valuation allowance for deferred tax assets	$ 7,976	$ 7,930	$ 7,906	$ 8,807
Increase (decrease) in valuation allowances	46	24	(901)
Deferred tax asset valuation allowance
Valuation Allowance [Line Items]
Valuation allowance for deferred tax assets	$ 8,000	$ 7,900	$ 7,900