Restructuring - Schedule of Restructuring Activities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Restructuring Reserve
Charges	$ 2	$ 152	$ 14	$ 304
Cash payments			(540)	$ (688)
Total
Restructuring Reserve
Balance at the beginning of the period			254
Charges			14
Cash payments			(167)
Non-cash items			0
Balance at the end of the period	101		101
Total costs incurred to date, as of July 31, 2018	2,237		2,237
Total costs expected to be incurred, as of July 31, 2018	2,237		2,237
Employee Severance | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period			219
Charges			5
Cash payments			(147)
Non-cash items			(3)
Balance at the end of the period	74		74
Total costs incurred to date, as of July 31, 2018	747		747
Total costs expected to be incurred, as of July 31, 2018	747		747
Infrastructure and other | 2015 Plan
Restructuring Reserve
Balance at the beginning of the period			17
Charges			(2)
Cash payments			(8)
Non-cash items			4
Balance at the end of the period	11		11
Total costs incurred to date, as of July 31, 2018	78		78
Total costs expected to be incurred, as of July 31, 2018	78		78
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		1
Total costs incurred to date, as of July 31, 2018	145		145
Total costs expected to be incurred, as of July 31, 2018	145		145
Employee Severance and EER | 2012 Plan
Restructuring Reserve
Balance at the beginning of the period			16
Charges			12
Cash payments			(12)
Non-cash items			(1)
Balance at the end of the period	15		15
Total costs incurred to date, as of July 31, 2018	1,267		1,267
Total costs expected to be incurred, as of July 31, 2018	$ 1,267		$ 1,267