Stockholders' Equity (Details 2) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Oct. 31, 2011	Oct. 31, 2015
Stockholders' Equity
Common Stock, Dividends, Per Share, Declared	$ 0.25	$ 0.32
Repurchases of common stock (in shares)	68.0	36.0
Payment in connection with repurchases of shares	$ 797	$ 1,571
Share repurchases that will be settled in subsequent period	1.6
Share repurchase authorization remaining	$ 1,200
Share repurchase authorization increase after balance sheet date			$ 10,000
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax (provision) benefit on unrealized gains (losses) arising during the period	16	(179)
Net change	(1,122)			$ (6,302)
Net revenue	12,246	13,858
Cost of products	11,318	12,740
Interest and other, net	(94)	(121)
Earnings from continuing operations before taxes	834	997
Other comprehensive income, net of taxes	99	206
Reclassifications of losses (gains) into earnings
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Other comprehensive income, net of taxes	99	206
Change in unrealized gains on available-for-sale securities
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax provision (benefit) on other comprehensive income		(15)
Tax (provision) benefit on unrealized gains (losses) arising during the period		(15)
Other comprehensive (losses) income before reclassifications		31
Net change in unrealized (losses) gains on available-for-sale securities		31
Change in unrealized (losses) gains on cash flow hedges
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax provision (benefit) on other comprehensive income	11	(201)
Tax provision (benefit) on (gains) losses	8	98
Tax (provision) benefit on unrealized gains (losses) arising during the period	19	(103)
Other comprehensive (losses) income before reclassifications	116	430
(Gains) losses reclassified into earnings	(26)	(236)
Net change in unrealized (losses) gains on derivatives qualifying as hedges	90	194
Change in unrealized (losses) gains on cash flow hedges | Reclassifications of losses (gains) into earnings
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Net revenue	(78)	(334)
Cost of products	40	26
Other operating expenses		4
Interest and other, net	4	(30)
Earnings from continuing operations before taxes	(34)	(334)
Change in unrealized components of defined benefit plans
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax (provision) benefit on unrealized gains (losses) arising during the period	(3)	(14)
Net change in unrealized gains (losses) on benefit plans	9	96
Amortization of actuarial loss and prior service benefit
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax provision (benefit) on (gains) losses	(3)	(14)
Losses (gains) adjustments reclassified into earnings	$ 9	98
Curtailments, settlements and other
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Net change in unrealized gains (losses) on other adjustments		(2)
Change in cumulative translation adjustment
Changes and reclassifications related to Other Comprehensive (Loss) Income, net of taxes
Tax (provision) benefit on unrealized gains (losses) arising during the period		(47)
Net change in unrealized gains (losses) in translation adjustment		$ (115)