| **Postretirement Benefits - Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions** | Apr. 30, 2016 | Oct. 31, 2015 |
|------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| **Defined Benefit Plan Disclosure [Line Items]**                                                                                         |          |          |
| Noncurrent liability                                                                                                                     | $ (2,945)     | $ (2,995)     |
| Net liability recognized                                                                                                                 | $ (3,037)     | $ (3,088)     |

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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
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| - Definition
This represents the entire liability recognized in the balance sheet that is associated with the defined benefit plans.
+ References
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| - Definition
This represents the noncurrent liability for underfunded plans recognized in the balance sheet that is associated with the defined benefit pension plans and other postretirement defined benefit plans.
+ References
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