Summary of Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Nov. 01, 2018	Jul. 31, 2019	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total costs and expenses			$ 54,879	$ 54,641	$ 48,688
Interest and other, net			(1,354)	(818)	$ (92)
ASU 2018-02 | Early adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from accumulated other comprehensive income to accumulated deficit		$ 69
ASU 2017-07 | Total cost and expenses
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Total costs and expenses				$ 233
ASU 2017-07 | Interest and other
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Interest and other, net			(233)
ASU 2016-16
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net reduction in prepaid taxes	$ 353
Adjustment for deferred tax asset adjusted through accumulated deficit			$ 47
Adjustments under Topic 606
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ 212