Stock-Based Compensation - Stock Options (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized pre-tax stock-based compensation expense related to non-vested restricted stock awards	$ 7
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	12	$ 20	$ 109
Total grant date fair value of options vested	$ 3	$ 9	$ 12
Remaining weighted-average vesting period (less than)	1 year 6 months

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

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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.

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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

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- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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