Equity Method Investments (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
		Oct. 31, 2017	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015	May 31, 2016
Schedule of Equity Method Investments [Line Items]
Investments in equity interests		$ 2,535	$ 2,535	$ 2,648
Loss from equity interests	[1]		23	76	$ 2
Equity Method Investee | H3C
Schedule of Equity Method Investments [Line Items]
Sales to related party			1,200	500
Purchases from related party			331	169
Payable to H3C		64	64	71
H3C
Schedule of Equity Method Investments [Line Items]
Investments in equity interests		$ 2,500	$ 2,500	$ 2,600
Ownership		49.00%	49.00%	49.00%		49.00%
Cash dividend		$ 98
Basis difference						$ 2,534
Equity method goodwill						1,674
Intangible assets						749
In-process research and development						188
Deferred tax liabilities						(152)
Other						$ 75
Weighted-average useful life			5 years
Loss from equity interests			$ 23	$ 76
Amortization of difference in basis			155	93
Investment's earnings			127	32
Elimination of intra-entity sales			$ 5	$ 15
Unisplendour | H3C
Schedule of Equity Method Investments [Line Items]
Ownership						51.00%

[1] Primarily represents the Company’s ownership interest in the net earnings of H3C, which the Company records as an equity method investment.