Overview and Basis of Presentation (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | |
|---|---|---|---|
Apr. 30, 2018 |
Apr. 30, 2018 |
Apr. 30, 2017 |
|
| Segment Reporting Information [Line Items] | |||
| Net excess tax benefits | $ 28 | $ 42 | |
| Net cash provided by (used in) operating activities | 389 | $ (451) | |
| Net cash provided by financing activities | $ (1,713) | (625) | |
| Accounting Standards Update 2016-09, Statutory Tax Withholding Component | |||
| Segment Reporting Information [Line Items] | |||
| Net cash provided by (used in) operating activities | (377) | ||
| Net cash provided by financing activities | $ 377 | ||