Financial Instruments - Pre-tax Effect of Derivative Instruments and Related Hedged Items in a Fair Value Hedging Relationship (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017
Interest rate contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in Earnings on Derivative	$ 16	$ 23	$ (194)	$ (202)
Gains (Losses) Recognized in Earnings on Related Hedged Item	(16)	(23)	194	202
Cash flow hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in Other Comprehensive Income (OCI) on Derivatives (Effective Portion)	149	(133)	50	7
Interest and other, net \| Cash flow hedges \| Foreign exchange contracts
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in Other Comprehensive Income (OCI) on Derivatives (Effective Portion)	$ 28	$ 28	$ (9)	$ 170

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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Total amount of gain (loss) derived from fair value hedges recognized in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

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