Taxes on Earnings (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015	Oct. 31, 2015
Differences between the U.S. federal statutory income tax rate and HP's effective tax rate
Effective tax rate (as a percent)	21.10%	20.20%	21.60%	21.60%
U.S. federal statutory income tax rate (as a percent)			35.00%
Tax benefit arising from the retroactive research and development credit			$ 41	$ 26
Tax benefits from restructuring charges	$ 32	$ 4	38	7
Various tax (benefits) charges related to discrete items	(33)	$ 2	(86)	(15)
Tax expense from provision to return adjustments				$ 29
Unrecognized tax benefits	9,300		9,300
Unrecognized tax benefits that would affect effective tax rate if realized	3,200		3,200
Increase in unrecognized tax benefits			59
Distribution of liabilities related solely to uncertain tax positions	741		741
Accrued income tax payable for interest and penalties	136		136
Reasonably possible reduction in existing unrecognized tax benefits within the next 12 months	2		2
Advance royalty proceeds received from multi-year intercompany licensing arrangements	519				$ 3,800
Royalty recognition term					5 years
Hewlett-Packard Enterprise
Differences between the U.S. federal statutory income tax rate and HP's effective tax rate
Receivable for certain tax liabilities under the Tax Matters Agreement	$ 883		$ 883