Retirement and Post-Retirement Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2015	Oct. 31, 2014
Defined Benefit Plan And Deferred Profit Sharing Plan Disclosure [Line Items]
Plan Assets	$ 11,819	$ 12,807
Projected Benefit Obligation	13,458	14,584
U.S. Defined Benefit Plans
Defined Benefit Plan And Deferred Profit Sharing Plan Disclosure [Line Items]
Plan Assets	11,077	11,979
Projected Benefit Obligation	$ 12,716	13,756
Post-Retirement Benefit Plans
Post Retirement Benefit Plans
Eligible Age for HP Retirement Medical Savings Account Plan	45 years
DPSP
Defined Benefit Plan And Deferred Profit Sharing Plan Disclosure [Line Items]
Plan Assets	$ 742	828
Projected Benefit Obligation	$ 742	$ 828