Segment Information - Reconciliation of Segment Operating Results (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Net revenue:
Net revenue	$ 8,209	$ 8,005	$ 23,210	$ 25,046
Earnings before taxes:
Total segment earnings from operations	147	2,645	785	3,568
Amortization of intangible assets	(132)	(111)	(340)	(331)
Restructuring charges	(165)	(93)	(399)	(346)
Transformation costs	(31)	0	(31)	0
Acquisition and other related charges	(56)	(34)	(151)	(114)
Separation costs	(186)	(76)	(412)	(246)
Gain on H3C Divestiture	0	2,169	0	2,169
Interest and other, net	(97)	(69)	(260)	(195)
Tax indemnification adjustments	10	60	(1)	6
Earnings (loss) from equity interests	1	(72)	(24)	(72)
Earnings from continuing operations before taxes	61	2,564	500	3,307
Operating Segment
Net revenue:
Net revenue	8,406	8,350	24,075	26,157
Earnings before taxes:
Total segment earnings from operations	849	1,019	2,609	3,196
Elimination of intersegment net revenue and other
Net revenue:
Net revenue	197	345	865	1,111
Segment Reconciling Items
Earnings before taxes:
Corporate and unallocated costs and eliminations	(59)	(129)	(220)	(430)
Stock-based compensation expense	(97)	(100)	(316)	(330)
Amortization of intangible assets	(132)	(111)	(340)	(331)
Restructuring charges	(165)	(93)	(399)	(346)
Transformation costs	(31)	0	(31)	0
Acquisition and other related charges	(56)	(34)	(151)	(114)
Separation costs	(186)	(76)	(412)	(246)
Defined benefit plan settlement charges and remeasurement (benefit)	24	0	45	0
Gain on H3C Divestiture	0	2,169	0	2,169
Interest and other, net	(97)	(69)	(260)	(195)
Tax indemnification adjustments	10	60	(1)	6
Earnings (loss) from equity interests	$ 1	$ (72)	$ (24)	$ (72)