Restructuring - Schedule of Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended
	Jan. 31, 2019	Jan. 31, 2018
Restructuring Reserve
Cash payments	$ (110)	$ (226)
Total
Restructuring Reserve
Balance at the beginning of the period	84
Cash payments	(12)
Balance at the end of the period	72
Total costs incurred to date, as of January 31, 2019	2,242
Total costs expected to be incurred, as of January 31, 2019	2,242
Employee Severance | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period	62
Cash payments	(9)
Balance at the end of the period	53
Total costs incurred to date, as of January 31, 2019	751
Total costs expected to be incurred, as of January 31, 2019	751
Infrastructure and other | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period	10
Cash payments	(1)
Balance at the end of the period	9
Total costs incurred to date, as of January 31, 2019	78
Total costs expected to be incurred, as of January 31, 2019	78
Infrastructure and other | 2012 Plan
Restructuring Reserve
Balance at the beginning of the period	1
Cash payments	0
Balance at the end of the period	1
Total costs incurred to date, as of January 31, 2019	145
Total costs expected to be incurred, as of January 31, 2019	145
Employee Severance and EER | 2012 Plan
Restructuring Reserve
Balance at the beginning of the period	11
Cash payments	(2)
Balance at the end of the period	9
Total costs incurred to date, as of January 31, 2019	1,268
Total costs expected to be incurred, as of January 31, 2019	$ 1,268