Taxes on Earnings (Detail 2)	9 Months Ended	12 Months Ended
	Jul. 31, 2018	Oct. 31, 2018	Oct. 31, 2017	Oct. 31, 2016
Differences between the U.S. federal statutory income tax rate and HP's effective tax rate
U.S. federal statutory income tax rate	23.30%	23.30%	35.00%	35.00%
State income taxes, net of federal tax benefit		4.30%	3.00%	1.00%
Lower rates in other jurisdictions, net		(121.40%)	(426.30%)	(24.50%)
Valuation allowance		(59.80%)	310.00%	(14.70%)
U.S. permanent differences		39.30%	27.80%	(2.30%)
Uncertain tax positions		(694.80%)	(8.40%)	23.10%
Impacts of the Tax Act		158.00%	0.00%	0.00%
Other, net		0.40%	(1.40%)	(1.50%)
Effective tax rate (as a percent)		(650.70%)	(60.30%)	16.10%