Segment Information - Segment Assets (Details) - USD ($) $ in Millions |
Apr. 30, 2018 |
Oct. 31, 2017 |
|---|---|---|
| Segment Reporting Information [Line Items] | ||
| Assets | $ 59,876 | $ 61,406 |
| Operating Segment | Hybrid IT | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 26,488 | 25,923 |
| Operating Segment | Intelligent Edge | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 3,042 | 3,002 |
| Operating Segment | Financial Services | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 13,560 | 13,470 |
| Operating Segment | Corporate Investments | ||
| Segment Reporting Information [Line Items] | ||
| Assets | 160 | 161 |
| Corporate, Non-Segment | ||
| Segment Reporting Information [Line Items] | ||
| Assets | $ 16,626 | $ 18,850 |