v3.7.0.1
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