Accounting for Leases as a Lessor - Gross Financing Receivables and Related Allowance Evaluated for Loss (Details) - USD ($) $ in Millions	Apr. 30, 2020	Oct. 31, 2019	Oct. 31, 2018
Leases [Abstract]
Gross financing receivables collectively evaluated for loss	$ 8,239	$ 8,255
Gross financing receivables individually evaluated for loss	439	397
Financing receivables, gross	8,678	8,652
Allowance for financing receivables collectively evaluated for loss	85	84
Allowance for financing receivables individually evaluated for loss	41	47
Total	$ 126	$ 131	$ 120

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement.

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