Goodwill and Intangible Assets - Intangibles (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Apr. 30, 2017	Apr. 30, 2016	Apr. 30, 2017	Apr. 30, 2016	Oct. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 6,353		$ 6,353		$ 5,762
Amortizable intangible assets, accumulated amortization	(1,710)		(1,710)		(1,575)
Finite-lived Intangible Assets, Accumulated Impairment Losses			(3,103)		(3,103)
Total Intangible Assets- Net	1,540		1,540		1,084
Amortizable intangible assets, net	1,455		1,455
Fully amortized intangibles	73		73
Amortization of intangible assets	107	$ 101	208	$ 220
SGI
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	579		579
In-process research and development
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	85		85		0
Amortizable intangible assets, accumulated amortization	0		0		0
Finite-lived Intangible Assets, Accumulated Impairment Losses			0		0
Amortizable intangible assets, net	85		85		0
In-process research and development | SGI
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	85		85
Customer contracts, customer lists and distribution agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	1,488		1,488		1,394
Amortizable intangible assets, accumulated amortization	(305)		(305)		(322)
Finite-lived Intangible Assets, Accumulated Impairment Losses			(856)		(856)
Amortizable intangible assets, net	327		327		216
Developed and core technology and patents
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	4,565		4,565		4,190
Amortizable intangible assets, accumulated amortization	(1,378)		(1,378)		(1,232)
Finite-lived Intangible Assets, Accumulated Impairment Losses			(2,138)		(2,138)
Amortizable intangible assets, net	1,049		1,049		820
Trade name and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	215		215		178
Amortizable intangible assets, accumulated amortization	(27)		(27)		(21)
Finite-lived Intangible Assets, Accumulated Impairment Losses			(109)		(109)
Amortizable intangible assets, net	$ 79		$ 79		$ 48