Restructuring Activities - Summary of Amount of Restructuring Severance Liabilities Related to Program (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Restructuring Cost And Reserve [Line Items]
Utilization (cash paid)	$ (13)	$ (1)	$ (15)	$ (4)
2025 Restructuring program
Restructuring Cost And Reserve [Line Items]
Beginning balance			0
Restructuring reserve			12
Utilization (cash paid)	(5)	0	(6)	0
Ending balance	6		6
2023 Restructuring program
Restructuring Cost And Reserve [Line Items]
Beginning balance			18
Restructuring reserve			(2)
Utilization (cash paid)	(8)	$ (1)	(9)	$ (4)
Ending balance	$ 7		$ 7

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
-SubTopic 10
-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 420
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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-URI https://asc.fasb.org/1943274/2147482017/420-10-50-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability.

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