Goodwill and Intangible Assets - Intangibles (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Oct. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	$ 5,937		$ 5,762
Amortizable intangible assets, accumulated amortization	(1,670)		(1,575)
Finite-lived Intangible Assets, Accumulated Impairment Losses	(3,103)		(3,103)
Total Intangible Assets- Net	1,164		1,084
Amortizable intangible assets, net	1,134
Amortization of intangible assets	101	$ 218
SGI
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	150
In-process research and development
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	30		0
Amortizable intangible assets, accumulated amortization	0		0
Finite-lived Intangible Assets, Accumulated Impairment Losses	0		0
Amortizable intangible assets, net	30		0
In-process research and development | SGI
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets, gross	30
Customer contracts, customer lists and distribution agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	1,453		1,394
Amortizable intangible assets, accumulated amortization	(342)		(322)
Finite-lived Intangible Assets, Accumulated Impairment Losses	(856)		(856)
Amortizable intangible assets, net	255		216
Developed and core technology and patents
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	4,261		4,190
Amortizable intangible assets, accumulated amortization	(1,304)		(1,232)
Finite-lived Intangible Assets, Accumulated Impairment Losses	(2,138)		(2,138)
Amortizable intangible assets, net	819		820
Trade name and trademarks
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets, gross	193		178
Amortizable intangible assets, accumulated amortization	(24)		(21)
Finite-lived Intangible Assets, Accumulated Impairment Losses	(109)		(109)
Amortizable intangible assets, net	$ 60		$ 48