Receivables, Loans, Notes Receivable, and Others (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Accounts and Financing Receivable, after Allowance for Credit Loss, Current and Noncurrent [Abstract]
Accounts Receivable, Sale	$ 129	$ 0
Outstanding Receivables Sold under Factoring Agreements	127
Accounts Receivable, before Allowance for Credit Loss, Current	5,723	5,467
Less: Allowance for expected credit losses	(110)	(173)	[1]
Accounts receivable - net	5,613	5,294
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Accounts Receivable, Allowance for Credit Loss, Beginning Balance	173
Accounts Receivable, Credit Loss Expense (Reversal)	(3)
Accounts Receivable, Allowance for Credit Loss, Writeoff	(65)
Accounts Receivable, Allowance for Credit Loss, Currency translation	1
Accounts Receivable, Allowance for Credit Loss, Other	4
Accounts Receivable, Allowance for Credit Loss, Ending Balance	$ 110	$ 173

[1] (1) Allowance for doubtful accounts as of September 30, 2020, prior to the adoption of ASU 2016-13.