Segment Information - Operating Results (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2017	Oct. 31, 2016	Oct. 31, 2015
Segment Reporting Information
Net revenue	$ 28,871	$ 30,280	$ 31,077
Segment earnings (loss) from operations	625	3,903	1,946
Enterprise Group
Segment Reporting Information
Net revenue	25,294	26,592	27,193
Financial Services
Segment Reporting Information
Net revenue	3,574	3,097	3,200
Corporate Investments
Segment Reporting Information
Net revenue	3	591	684
Intersegment Eliminations
Segment Reporting Information
Net revenue	945	1,280	1,334
Intersegment Eliminations | Enterprise Group
Segment Reporting Information
Net revenue	917	1,187	1,318
Intersegment Eliminations | Financial Services
Segment Reporting Information
Net revenue	28	93	16
Intersegment Eliminations | Corporate Investments
Segment Reporting Information
Net revenue	0	0	0
Operating segments
Segment Reporting Information
Net revenue	29,816	31,560	32,411
Segment earnings (loss) from operations	2,869	3,665	4,077
Operating segments | Enterprise Group
Segment Reporting Information
Net revenue	26,211	27,779	28,511
Segment earnings (loss) from operations	2,707	3,569	3,999
Operating segments | Financial Services
Segment Reporting Information
Net revenue	3,602	3,190	3,216
Segment earnings (loss) from operations	304	336	349
Operating segments | Corporate Investments
Segment Reporting Information
Net revenue	3	591	684
Segment earnings (loss) from operations	$ (142)	$ (240)	$ (271)