Segment Information - Revenue by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Apr. 30, 2020	Apr. 30, 2019
Segment Reporting Information [Line Items]
Total net revenue	$ 6,009	$ 7,150	$ 12,958	$ 14,703
Total Americas
Segment Reporting Information [Line Items]
Total net revenue	2,316	2,667	5,102	5,672
United States
Segment Reporting Information [Line Items]
Total net revenue	1,906	2,184	4,224	4,685
Americas excluding U.S.
Segment Reporting Information [Line Items]
Total net revenue	410	483	878	987
Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Total net revenue	2,198	2,727	4,758	5,637
Asia Pacific and Japan
Segment Reporting Information [Line Items]
Total net revenue	$ 1,495	$ 1,756	$ 3,098	$ 3,394