Taxes on Earnings - Uncertain Tax Positions (Narrative) (Details) $ in Millions	12 Months Ended
	Oct. 31, 2025 USD ($) country	Oct. 31, 2024 USD ($)	Oct. 31, 2023 USD ($)	Oct. 31, 2022 USD ($)
Income Tax Disclosure [Abstract]
Unrecognized tax benefits	$ 865	$ 1,217	$ 1,137	$ 1,045
Unrecognized tax benefits that would affect effective tax rate if realized	656
Increase in gross unrecognized tax benefits	(352)
Accrued income tax for interest and penalties	$ 122	$ 135	$ 102
Likelihood of no resolution period	12 months
Reasonably possible decrease in existing unrecognized tax benefits within the next 12 months	$ 42
Number of other countries in which HP is subject to income taxes | country	60
Undistributed earnings from non-U.S. operations	$ 5,100