Restructuring (Details) $ in Millions	3 Months Ended		41 Months Ended
	Jan. 31, 2017 USD ($) position	Jan. 31, 2016 USD ($)	Oct. 31, 2015 position	Oct. 31, 2016 USD ($)
Restructuring Reserve
Restructuring charges	$ 177	$ 311
Short-term portion of restructuring reserve, recorded in Accrued restructuring	510			$ 671
Long-term portion of restructuring reserve, recorded in Other liabilities	135			$ 166
Restructuring Plan All
Restructuring Reserve
Liability as of October 31, 2016	837
Restructuring charges	177
Cash payments	(326)
Non-cash items	(43)
Liability as of January 31, 2017	645
Total costs incurred to date, as of January 31, 2017	9,328
Total costs expected to be incurred, as of January 31, 2017	10,255
Fiscal 2015 Plan
Restructuring Reserve
Total costs expected to be incurred	$ 2,600
Expected number of positions to be eliminated | position	30,000
Fiscal 2015 Plan | Employee Severance
Restructuring Reserve
Liability as of October 31, 2016	$ 629
Restructuring charges	123
Cash payments	(260)
Non-cash items	(18)
Liability as of January 31, 2017	474
Total costs incurred to date, as of January 31, 2017	1,406
Total costs expected to be incurred, as of January 31, 2017	2,158
Total costs expected to be incurred	2,200
Fiscal 2015 Plan | Infrastructure and other
Restructuring Reserve
Liability as of October 31, 2016	35
Restructuring charges	58
Cash payments	(37)
Non-cash items	(22)
Liability as of January 31, 2017	34
Total costs incurred to date, as of January 31, 2017	276
Total costs expected to be incurred, as of January 31, 2017	451
Total costs expected to be incurred	400
Fiscal 2012 Plan
Restructuring Reserve
Total costs incurred to date, as of January 31, 2017	4,500
Expected number of positions to be eliminated | position			42,100
Fiscal 2012 Plan | Employee Severance
Restructuring Reserve
Total costs incurred to date, as of January 31, 2017	4,000
Fiscal 2012 Plan | Infrastructure and other
Restructuring Reserve
Liability as of October 31, 2016	23
Restructuring charges	0
Cash payments	(2)
Non-cash items	0
Liability as of January 31, 2017	21
Total costs incurred to date, as of January 31, 2017	546
Total costs expected to be incurred, as of January 31, 2017	546
Fiscal 2012 Plan | Employee Severance and EER
Restructuring Reserve
Liability as of October 31, 2016	139
Restructuring charges	0
Cash payments	(26)
Non-cash items	(3)
Liability as of January 31, 2017	110
Total costs incurred to date, as of January 31, 2017	3,980
Total costs expected to be incurred, as of January 31, 2017	3,980
Other Plans | Employee Severance
Restructuring Reserve
Liability as of October 31, 2016	1
Restructuring charges	0
Cash payments	0
Non-cash items	0
Liability as of January 31, 2017	1
Total costs incurred to date, as of January 31, 2017	1,997
Total costs expected to be incurred, as of January 31, 2017	1,997
Other Plans | Infrastructure and other
Restructuring Reserve
Liability as of October 31, 2016	10
Restructuring charges	(4)
Cash payments	(1)
Non-cash items	0
Liability as of January 31, 2017	5
Total costs incurred to date, as of January 31, 2017	1,123
Total costs expected to be incurred, as of January 31, 2017	$ 1,123