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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 |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482017/420-10-50-1 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 17 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482740/230-10-45-17 + Details
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- Definition Amount of expense (reversal of expense) which increases (decreases) the restructuring reserve from an adjustment to a previously accrued restructuring liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.P.4.b.2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147479823/420-10-S99-2 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 420 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(2) -Publisher FASB -URI https://asc.fasb.org/1943274/2147482017/420-10-50-1 + Details
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