Taxes on Earnings - Schedule of Deferred Tax Assets for Net Operating Loss Carryforwards (Details) - USD ($) $ in Millions	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Operating Loss Carryforwards [Line Items]
Gross NOLs	$ 29,323
Valuation allowance	(7,930)	$ (7,906)	$ (8,807)	$ (8,520)
Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	7,679
Valuation allowance	(7,438)
Federal
Operating Loss Carryforwards [Line Items]
Gross NOLs	372
Federal | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	78
Valuation allowance	(19)
State
Operating Loss Carryforwards [Line Items]
Gross NOLs	2,634
State | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	167
Valuation allowance	(62)
Foreign
Operating Loss Carryforwards [Line Items]
Gross NOLs	26,317
Foreign | Operating loss carryforwards
Operating Loss Carryforwards [Line Items]
Deferred Taxes on NOLs	7,434
Valuation allowance	$ (7,357)