Taxes on Earnings (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($) country	Apr. 30, 2016 USD ($)	Oct. 31, 2016 USD ($)
Differences between the U.S. federal statutory income tax rate and HP's effective tax rate
Effective tax rate (as a percent)	582.20%	2.40%	152.80%	7.90%
Valuation allowance	$ 473		$ 473
Accrued divestiture tax	110		$ 110
U.S. federal statutory income tax rate (as a percent)			35.00%
Net income tax charges (benefits) related to discrete items	506	$ (92)	$ 471	$ (174)
Other benefits	(473)
Income tax charges for various prior period adjustments	(79)		$ (141)
Number of countries other than the United States where the entity is subject to income tax | country			110
Unrecognized tax benefits	11,500		$ 11,500		$ 11,400
Unrecognized tax benefits that would affect effective tax rate if realized	3,000		3,000		2,900
Accrued income tax for interest and penalties	403		$ 403		394
Likelihood of no resolution period			12 months
Reasonably possible reduction in existing unrecognized tax benefits within the next 12 months	2,700		$ 2,700
Likelihood of conclusion period for certain federal, foreign and state tax issues			12 months
Deferred tax assets - long-term	3,491		$ 3,491		3,830
Deferred tax liabilities - long-term	(83)		(83)		(98)
Deferred tax assets net of deferred tax liabilities	$ 3,408		3,408		3,732
Advance royalty proceeds received from multi-year intercompany licensing arrangements			$ 439		$ 3,700
Royalty recognition term			5 years