Restructuring - Schedule of Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2018	Jan. 31, 2017
Restructuring Reserve
Charges	$ 3	$ 83
Cash payments	(226)	$ (326)
Total
Restructuring Reserve
Balance at the beginning of the period	254
Charges	3
Cash payments	(118)
Non-cash items	8
Balance at the end of the period	147
Total costs incurred to date, as of January 31, 2018	2,226
Total costs expected to be incurred, as of January 31, 2018	2,226
Employee Severance | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period	219
Charges	2
Cash payments	(108)
Non-cash items	6
Balance at the end of the period	119
Total costs incurred to date, as of January 31, 2018	744
Total costs expected to be incurred, as of January 31, 2018	744
Infrastructure and other | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period	17
Charges	2
Cash payments	(4)
Non-cash items	0
Balance at the end of the period	15
Total costs incurred to date, as of January 31, 2018	82
Total costs expected to be incurred, as of January 31, 2018	82
Infrastructure and other | 2012 Plan
Restructuring Reserve
Balance at the beginning of the period	2
Charges	(1)
Cash payments	0
Non-cash items	0
Balance at the end of the period	1
Total costs incurred to date, as of January 31, 2018	145
Total costs expected to be incurred, as of January 31, 2018	145
Employee Severance and EER | 2012 Plan
Restructuring Reserve
Balance at the beginning of the period	16
Charges	0
Cash payments	(6)
Non-cash items	2
Balance at the end of the period	12
Total costs incurred to date, as of January 31, 2018	1,255
Total costs expected to be incurred, as of January 31, 2018	$ 1,255