Taxes on Earnings (Details) (USD $)	3 Months Ended			6 Months Ended		12 Months Ended
	Apr. 30, 2015	Jan. 31, 2015	Apr. 30, 2014	Apr. 30, 2015 item	Apr. 30, 2014	Oct. 31, 2014
Taxes on Earnings
Tax benefit from the retroactive research and development credit				$ 47,000,000
Differences between the U.S. federal statutory income tax rate and HP's effective tax rate
Effective tax rate (as a percent)	21.70%		22.80%	21.80%	22.50%
U.S. federal statutory income tax rate (as a percent)	35.00%
Net tax charges (Benefits) related to discrete items	(104,000,000)		13,000,000	(185,000,000)	35,000,000
Tax benefits from separation costs	86,000,000			115,000,000
Tax benefits from restructuring charges	32,000,000		30,000,000	53,000,000	45,000,000
Various tax charges related to discrete items	14,000,000		43,000,000	30,000,000	80,000,000
Number of countries other than the United States where the entity is subject to income tax				105
Income tax examination, proposed assessment amount	680,000,000			680,000,000
Unrecognized Tax Benefits	4,200,000,000			4,200,000,000
Unrecognized tax benefits that would affect effective tax rate if realized	2,300,000,000			2,300,000,000
Accrued income tax payable for interest and penalties	246,000,000			246,000,000
Likelihood of no resolution period				12 months
Likelihood of conclusion period for certain federal, foreign and state tax issues				12 months
Reasonably possible reduction in existing unrecognized tax benefits within the next 12 months	1,500,000,000			1,500,000,000
Current and long-term deferred tax assets and deferred tax liabilities
Current deferred tax assets	3,149,000,000			3,149,000,000		2,754,000,000
Current deferred tax liabilities	(264,000,000)			(264,000,000)		(284,000,000)
Long-term deferred tax assets	942,000,000			942,000,000		740,000,000
Long-term deferred tax liabilities	(1,738,000,000)			(1,738,000,000)		(1,124,000,000)
Net deferred tax assets net of deferred tax liabilities	2,089,000,000			2,089,000,000		2,086,000,000
Advance royalty proceeds received from intercompany advanced royalty payments and licensing arrangements		8,200,000,000				11,500,000,000
Recognition of net long term deferred tax assets from intercompany licensing arrangement				$ 2,100,000,000		$ 1,700,000,000
Royalty recognition term	5 years			5 years		15 years
Number of independent publicly-traded companies				2