Segment Information - Segment Operating Results from Continuing Operations (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2017	Jul. 31, 2016
Segment Reporting Information [Line Items]
Net revenue	$ 8,209	$ 8,005	$ 23,210	$ 25,046
Segment earnings (loss) from operations	147	2,645	785	3,568
Intersegment net revenue and other
Segment Reporting Information [Line Items]
Net revenue	197	345	865	1,111
Operating Segment
Segment Reporting Information [Line Items]
Net revenue	8,406	8,350	24,075	26,157
Segment earnings (loss) from operations	849	1,019	2,609	3,196
Enterprise Group
Segment Reporting Information [Line Items]
Net revenue	6,606	6,367	18,647	20,119
Enterprise Group | Intersegment net revenue and other
Segment Reporting Information [Line Items]
Net revenue	185	248	712	837
Enterprise Group | Operating Segment
Segment Reporting Information [Line Items]
Net revenue	6,791	6,615	19,359	20,956
Segment earnings (loss) from operations	634	849	1,984	2,660
Software
Segment Reporting Information [Line Items]
Net revenue	708	666	1,999	2,089
Software | Intersegment net revenue and other
Segment Reporting Information [Line Items]
Net revenue	10	72	125	203
Software | Operating Segment
Segment Reporting Information [Line Items]
Net revenue	718	738	2,124	2,292
Segment earnings (loss) from operations	179	131	514	459
Financial Services
Segment Reporting Information [Line Items]
Net revenue	895	787	2,564	2,305
Financial Services | Intersegment net revenue and other
Segment Reporting Information [Line Items]
Net revenue	2	25	28	71
Financial Services | Operating Segment
Segment Reporting Information [Line Items]
Net revenue	897	812	2,592	2,376
Segment earnings (loss) from operations	70	80	226	253
Corporate Investments
Segment Reporting Information [Line Items]
Net revenue	0	185	0	533
Corporate Investments | Intersegment net revenue and other
Segment Reporting Information [Line Items]
Net revenue	0	0	0	0
Corporate Investments | Operating Segment
Segment Reporting Information [Line Items]
Net revenue	0	185	0	533
Segment earnings (loss) from operations	$ (34)	$ (41)	$ (115)	$ (176)