Stock-Based Compensation - Narrative (Details) $ in Millions	3 Months Ended	6 Months Ended
Apr. 30, 2017 USD ($)	Apr. 30, 2017 USD ($)
Stock-Based Compensation
Intrinsic value of options exercised	$ 14	$ 17
Unrecognized pre-tax, stock-based compensation expense	11	11
Restricted Stock Awards
Stock-Based Compensation
Unrecognized pre-tax stock-based compensation expense	$ 262	$ 262
Remaining weighted-average vesting period over which pre-tax stock-based compensation expense is expected to be recognized		1 year 4 months 24 days
Stock Options
Stock-Based Compensation
Remaining weighted-average vesting period over which pre-tax stock-based compensation expense is expected to be recognized		1 year 3 months 18 days

Unrecognized cost of unvested share-based compensation awards.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Unrecognized cost of unvested options awarded to employees as compensation.

+ References

No definition available.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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