Segment Information - Subsegments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Segment Reporting Information
Net revenue	$ 12,210	$ 13,057	$ 37,645	$ 38,659
Operating segments
Segment Reporting Information
Net revenue	12,751	13,692	39,344	40,419
Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	541	635	1,699	1,760
Enterprise Group
Segment Reporting Information
Net revenue	6,223	6,674	19,689	19,683
Enterprise Group | Operating segments
Segment Reporting Information
Net revenue	6,476	7,007	20,537	20,549
Enterprise Group | Operating segments | Servers
Segment Reporting Information
Net revenue	3,368	3,520	10,497	10,447
Enterprise Group | Operating segments | Technology Services
Segment Reporting Information
Net revenue	1,745	1,880	5,378	5,800
Enterprise Group | Operating segments | Networking
Segment Reporting Information
Net revenue	639	823	2,376	1,941
Enterprise Group | Operating segments | Storage
Segment Reporting Information
Net revenue	724	784	2,286	2,361
Enterprise Group | Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	253	333	848	866
Enterprise Services
Segment Reporting Information
Net revenue	4,534	4,779	13,559	14,179
Enterprise Services | Operating segments
Segment Reporting Information
Net revenue	4,725	4,976	14,136	14,786
Enterprise Services | Operating segments | Infrastructure Technology Outsourcing
Segment Reporting Information
Net revenue	2,866	3,036	8,579	9,039
Enterprise Services | Operating segments | Application and Business Services
Segment Reporting Information
Net revenue	1,859	1,940	5,557	5,747
Enterprise Services | Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	191	197	577	607
Software
Segment Reporting Information
Net revenue	666	821	2,089	2,452
Software | Operating segments
Segment Reporting Information
Net revenue	738	901	2,292	2,663
Software | Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	72	80	203	211
Financial Services
Segment Reporting Information
Net revenue	787	782	2,305	2,339
Financial Services | Operating segments
Segment Reporting Information
Net revenue	812	807	2,376	2,415
Financial Services | Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	25	25	71	76
Corporate Investments
Segment Reporting Information
Net revenue	0	1	3	6
Corporate Investments | Operating segments
Segment Reporting Information
Net revenue	0	1	3	6
Corporate Investments | Elimination of intersegment net revenue and other
Segment Reporting Information
Net revenue	$ 0	$ 0	$ 0	$ 0