Other Operating Income, Net and Other Non-Operating Income (Expense), Net - Other Non-Operating Income (Expense), Net (Details) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Component of Operating Income [Abstract]
Gains (losses) on foreign currency contracts, net	$ 9	$ (20)	$ 38
Gain (Loss) on Derivative Instruments, Net, Pretax	2	0	0
Pension and other postretirement plans non-service income, net	1	0	1
Total other non-operating income (expense), net	$ 12	$ (20)	$ 39

Amount before tax of foreign currency transaction realized and unrealized gain (loss) recognized in the income statement.

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Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

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Amount of expense (reversal of expense) for net periodic benefit cost components, excluding service cost component, of defined benefit plan. Amount includes, but is not limited to, interest cost, expected (return) loss on plan asset, amortization of prior service cost (credit), amortization of (gain) loss, amortization of transition (asset) obligation, settlement (gain) loss, curtailment (gain) loss and certain termination benefits.

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Amount of income (expense) related to nonoperating activities, classified as other.

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