Receivables, Loans, Notes Receivable, and Others (Details) - USD ($) $ in Millions	3 Months Ended
Dec. 31, 2020	Sep. 30, 2020
Accounts and Financing Receivable, after Allowance for Credit Loss, Current and Noncurrent [Abstract]
Accounts receivable	$ 5,350	$ 5,467
Less: Allowance for expected credit losses	(173)	(173)
Accounts receivable - net	5,177	$ 5,294
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	173
Provision for expected credit losses	7
Write-offs charged against the allowance for expected credit losses	(12)
Other (including impact of adoption of ASU 2016-13)	5
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 173

Accounts Receivable, Allowance for Credit Loss, Other

No definition available.

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- Definition

Amount, before allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

+ References

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- Definition

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

+ References

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- References

No definition available.

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- Definition

Amount of allowance for credit loss on accounts receivable.

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- Definition

Amount of allowance for credit loss on accounts receivable, classified as current.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

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- Definition

Amount of expense (reversal of expense) for expected credit loss on accounts receivable.

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