Allowance for Credit Losses - Narrative (Details) $ in Millions	6 Months Ended
Apr. 30, 2021 USD ($) class_receivable segment	Apr. 30, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of portfolio segments of finance receivables \| segment	2
Classes of receivables \| class_receivable	1
Retail portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired finance receivables \| $	$ 39	$ 25

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5258-111524

Name:	us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration