Restructuring (Details) $ in Millions	3 Months Ended		6 Months Ended		59 Months Ended
	Apr. 30, 2017 USD ($) position	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($) position	Apr. 30, 2016 USD ($)	Apr. 30, 2017 USD ($) position	Oct. 31, 2016 USD ($)
Restructuring Reserve
Restructuring charges	$ 118	$ 87	$ 234	$ 253
Short-term portion of restructuring reserve, recorded in Accrued restructuring	228		228		$ 228	$ 301
Long-term portion of restructuring reserve, recorded in Other liabilities	54		54		54	$ 52
Restructuring Plan All
Restructuring Reserve
Liability as of October 31, 2016			353
Restructuring charges			234
Cash payments			(257)
Non-cash items			(48)
Liability as of April 30, 2017	282		282		282
Total costs incurred to date, as of April 30, 2017	2,187		2,187		2,187
Total costs expected to be incurred, as of April 30, 2017	$ 2,574		$ 2,574		$ 2,574
Fiscal 2015 Plan
Restructuring Reserve
Expected number of positions to be eliminated | position			12,200
Number of positions still to be eliminated | position	4,000		4,000		4,000
Total costs expected to be incurred	$ 1,100		$ 1,100		$ 1,100
Fiscal 2015 Plan | Employee Severance
Restructuring Reserve
Liability as of October 31, 2016			277
Restructuring charges			198
Cash payments			(221)
Non-cash items			(23)
Liability as of April 30, 2017	231		231		231
Total costs incurred to date, as of April 30, 2017	642		642		642
Total costs expected to be incurred, as of April 30, 2017	850		850		850
Total costs expected to be incurred	800		800		800
Fiscal 2015 Plan | Infrastructure and other
Restructuring Reserve
Liability as of October 31, 2016			22
Restructuring charges			28
Cash payments			(14)
Non-cash items			(19)
Liability as of April 30, 2017	17		17		17
Total costs incurred to date, as of April 30, 2017	86		86		86
Total costs expected to be incurred, as of April 30, 2017	265		265		265
Total costs expected to be incurred	300		300		300
Fiscal 2012 Plan
Restructuring Reserve
Total costs incurred to date, as of April 30, 2017	1,400		1,400		$ 1,400
Expected number of positions to be eliminated | position					12,700
Fiscal 2012 Plan | Employee Severance
Restructuring Reserve
Total costs incurred to date, as of April 30, 2017	1,200		1,200		$ 1,200
Fiscal 2012 Plan | Infrastructure and other
Restructuring Reserve
Liability as of October 31, 2016			15
Restructuring charges			0
Cash payments			(4)
Non-cash items			(8)
Liability as of April 30, 2017	3		3		3
Total costs incurred to date, as of April 30, 2017	222		222		222
Total costs expected to be incurred, as of April 30, 2017	222		222		222
Fiscal 2012 Plan | Employee Severance and EER
Restructuring Reserve
Liability as of October 31, 2016			39
Restructuring charges			8
Cash payments			(18)
Non-cash items			2
Liability as of April 30, 2017	31		31		31
Total costs incurred to date, as of April 30, 2017	1,237		1,237		1,237
Total costs expected to be incurred, as of April 30, 2017	1,237		1,237		$ 1,237
Enterprise Services | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Restructuring Reserve
Restructuring charges	$ 98	$ 74	$ 159	$ 219