Acquisitions and Divestitures (Details) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended	9 Months Ended
	May. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Jul. 31, 2015 USD ($) item	Jul. 31, 2015 USD ($) item	Oct. 31, 2014 USD ($)
Acquisitions
Goodwill			$ 33,025	$ 33,025	$ 31,139
Divestitures
Proceeds from business divestitures				156
Aruba
Acquisitions
Total fair value of consideration	$ 2,800
Goodwill	1,800		1,800	1,800
Intangible assets	$ 628		628	$ 628
Weighted-average useful life	6 years
Aruba | In-process research and development
Acquisitions
Intangible assets	$ 149
Aggregate purchase price allocation
Acquisitions:
Number of acquisitions | item				4
Acquisitions
Total fair value of consideration				$ 3,041
Goodwill			1,959	1,959
Intangible assets			687	687
Net assets assumed			240	240
Aggregate purchase price allocation | In-process research and development
Acquisitions
Net tangible assets			$ 155	$ 155
Non-core divestitures | Disposal groups
Divestitures
Number of divestitures | item			3
Proceeds from business divestitures			$ 156
Disposal Group Disposed of by Other than Sale Not Discontinued Operations Spinoff | H3C | Forecast | HP China businesses
Divestitures
Entity ownership of HP China businesses (as a percent)		100.00%
Disposal Group Disposed of by Other than Sale Not Discontinued Operations Spinoff | Tsinghua Holdings Subsidiary | H3C | Forecast
Divestitures
Interest acquired (as a percent)		51.00%
Proceeds from divestiture of businesses		$ 2,300