Goodwill and Intangible Assets (Details 2) (USD $)	12 Months Ended												3 Months Ended	12 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012 Autonomy	Oct. 31, 2013 In-process research and development	Oct. 31, 2012 In-process research and development	Oct. 31, 2013 Customer contracts, customer lists and distribution agreements	Oct. 31, 2012 Customer contracts, customer lists and distribution agreements	Oct. 31, 2013 Developed and core technology and patents	Oct. 31, 2012 Developed and core technology and patents	Oct. 31, 2013 Trade name and trade marks	Oct. 31, 2012 Trade name and trade marks	Jul. 31, 2012 Compaq	Oct. 31, 2012 Compaq	Oct. 31, 2013 Developed and core technology, patents, product tradename and product trademarks
Intangible assets
Amortizable intangible assets, gross							$ 5,321,000,000	$ 5,807,000,000	$ 5,331,000,000	$ 6,580,000,000	$ 1,730,000,000	$ 1,732,000,000
Amortizable intangible assets, accumulated amortization	(4,886,000,000)	(5,281,000,000)					(2,709,000,000)	(2,625,000,000)	(1,966,000,000)	(2,501,000,000)	(211,000,000)	(155,000,000)
Intangible Assets, Accumulated Impairment Losses											(1,336,000,000)	(1,336,000,000)
Finite-lived Intangible Assets, Accumulated Impairment Losses	(4,330,000,000)	(4,330,000,000)					(856,000,000)	(856,000,000)	(2,138,000,000)	(2,138,000,000)
Amortizable intangible assets, net	3,166,000,000			800,000,000			1,756,000,000	2,326,000,000	1,227,000,000	1,941,000,000	183,000,000	241,000,000
Indefinite-lived intangible assets					3,000,000	7,000,000
Intangible assets, gross	12,385,000,000	14,126,000,000
Intangible assets, net	3,169,000,000	4,515,000,000
Weighted-Average Useful Lives	5 years						8 years				7 years				7 years
Amount of fully amortized intangible assets	1,700,000,000
Intangible asset impairment charges		4,300,000,000		3,100,000,000										1,200,000,000
Impairment charge		$ 18,035,000,000	$ 885,000,000										$ 1,200,000,000