Taxes on Earnings - Schedule of Deferred Tax Assets for Net Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Operating Loss Carryforwards [Line Items]
Gross NOLs	$ 29,253
Valuation allowance	(7,976)	$ (7,930)	$ (7,906)	$ (8,807)
Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	7,613
Valuation allowance	(7,161)
Federal
Operating Loss Carryforwards [Line Items]
Gross NOLs	291
Federal | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	61
Valuation allowance	(15)
State
Operating Loss Carryforwards [Line Items]
Gross NOLs	2,737
State | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	174
Valuation allowance	(61)
Foreign
Operating Loss Carryforwards [Line Items]
Gross NOLs	26,225
Foreign | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	7,378
Valuation allowance	$ (7,085)