Segment Information - Reconciliation of Segment Assets (Details) - USD ($) $ in Millions	Apr. 30, 2020	Oct. 31, 2019
Segment Reporting Information [Line Items]
Assets	$ 54,515	$ 51,803
Operating Segment | Compute
Segment Reporting Information [Line Items]
Assets	15,884	14,066
Operating Segment | HPC & MCS
Segment Reporting Information [Line Items]
Assets	6,006	6,819
Operating Segment | Storage
Segment Reporting Information [Line Items]
Assets	7,137	7,214
Operating Segment | A & PS
Segment Reporting Information [Line Items]
Assets	491	440
Operating Segment | Intelligent Edge
Segment Reporting Information [Line Items]
Assets	3,537	3,318
Operating Segment | Financial Services
Segment Reporting Information [Line Items]
Assets	14,702	14,700
Operating Segment | Corporate Investments
Segment Reporting Information [Line Items]
Assets	505	461
Corporate and unallocated assets
Segment Reporting Information [Line Items]
Assets	$ 6,253	$ 4,785