Accumulated Other Comprehensive Income (Loss) (Details 2) - USD ($) $ in Millions	12 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax [Abstract]
Foreign currency translation, tax	$ (5)	$ 29	$ (16)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax [Abstract]
Actuarial gains (losses) deferred during the period, tax	(150)	15	165
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax [Abstract]
Amortization of deferred actuarial (gains) losses into earnings, tax	(34)	(34)	(15)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax [Abstract]
Gains (losses) deferred during the period, tax	(15)	2	1
Reclassification of (gains) losses to sales and cost of sales, tax	$ 11	$ (2)	$ 0

Amount of tax expense (benefit) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount of tax (expense) benefit for reclassification adjustment from accumulated other comprehensive (income) loss of defined benefit plan.

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