Discontinued Operations - Schedule of Discontinued Operations, Financial Results (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Apr. 30, 2017	Apr. 30, 2018	Apr. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations	$ (72)	$ (134)	$ (118)	$ (118)
Separation and merger transactions | Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net revenue	0	3,124	0	7,629
Cost of revenue	0	2,201	0	5,620
Expenses	0	1,165	51	2,241
Interest and other, net(3)	72	3	68	3
Loss from discontinued operations before taxes	(72)	(245)	(119)	(235)
Benefit for taxes	0	111	1	117
Net loss from discontinued operations	$ (72)	$ (134)	$ (118)	$ (118)