Retirement and Post-Retirement Benefit Plans - Defined Contribution Plans (Narrative) (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Oct. 31, 2025 |
Oct. 31, 2024 |
Oct. 31, 2023 |
|
| Retirement Benefits [Abstract] | |||
| Total defined contribution expense | $ 132 | $ 133 | $ 131 |
| Defined Contribution Plan Disclosure [Line Items] | |||
| Total defined contribution expense | $ 132 | $ 133 | $ 131 |
| Employee service period | 3 years | ||
| HP 401(k) Plan | |||
| Defined Contribution Plan Disclosure [Line Items] | |||
| Employer matching contributions, as a percent | 100.00% | ||
| Percentage of maximum matching contribution | 4.00% | ||