Stockholders' Equity - Narrative (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	12 Months Ended
Jan. 31, 2020	Oct. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Remaining authorized repurchase amount	$ 2,300
Share Repurchase program
Equity, Class of Treasury Stock [Line Items]
Common stock retired (in shares)	12.8	0.5
Open share repurchases during period (in shares)	0.6
Repurchases of common stock recorded as a reduction to stockholders' equity	$ 204

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration