Segment Information - Operating Results (Details) - USD ($) $ in Millions	12 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2014
Segment Reporting Information
Net revenue	$ 50,123	$ 52,107	$ 55,123
Earnings (loss) from operations	4,150	1,523	2,335
Enterprise Group
Segment Reporting Information
Net revenue	26,017	26,668	26,812
Enterprise Services
Segment Reporting Information
Net revenue	18,094	19,010	21,297
Software
Segment Reporting Information
Net revenue	2,912	3,308	3,609
Financial Services
Segment Reporting Information
Net revenue	3,097	3,114	3,401
Corporate Investments
Segment Reporting Information
Net revenue	3	7	4
Intersegment Eliminations
Segment Reporting Information
Net revenue	2,356	2,451	2,437
Intersegment Eliminations | Enterprise Group
Segment Reporting Information
Net revenue	1,202	1,239	915
Intersegment Eliminations | Enterprise Services
Segment Reporting Information
Net revenue	778	796	1,101
Intersegment Eliminations | Software
Segment Reporting Information
Net revenue	283	314	324
Intersegment Eliminations | Financial Services
Segment Reporting Information
Net revenue	93	102	97
Intersegment Eliminations | Corporate Investments
Segment Reporting Information
Net revenue	0	0	0
Operating segments
Segment Reporting Information
Net revenue	52,479	54,558	57,560
Earnings (loss) from operations	5,653	5,595	5,742
Operating segments | Enterprise Group
Segment Reporting Information
Net revenue	27,219	27,907	27,727
Earnings (loss) from operations	3,459	3,862	3,909
Operating segments | Enterprise Services
Segment Reporting Information
Net revenue	18,872	19,806	22,398
Earnings (loss) from operations	1,457	1,019	818
Operating segments | Software
Segment Reporting Information
Net revenue	3,195	3,622	3,933
Earnings (loss) from operations	749	788	871
Operating segments | Financial Services
Segment Reporting Information
Net revenue	3,190	3,216	3,498
Earnings (loss) from operations	336	349	389
Operating segments | Corporate Investments
Segment Reporting Information
Net revenue	3	7	4
Earnings (loss) from operations	$ (348)	$ (423)	$ (245)