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v3.25.3

Derivatives - Additional Information (Detail) - USD ($) | 12 Months Ended |
--- | --- | ---
Sep. 30, 2025 | Sep. 30, 2024
Derivative [Line Items] |  |
Significant concentration of credit risk associated with our derivative instruments | $ 0 | $ 0
Maximum [Member] |  |
Derivative [Line Items] |  |
Fair value of derivative instruments not designated as hedges, liability | 1,000,000 | 1,000,000
Net Investment Hedge [Member] | Cross Currency Swaps [Member] |  |
Derivative [Line Items] |  |
Net cash interest received | 4,000,000 |
Fair value of swaps, liability | 12,000,000 |
Fair value of swaps, net asset |  | 1,000,000
Cumulative gain (loss) related to swaps | $ (8,000,000) | $ 5,000,000
Net Investment Hedge [Member] | Cross Currency Swaps [Member] | Fixed Rate Debt [Member] |  |
Derivative [Line Items] |  |
Derivative Instruments Frequency of Cash Settlements | semi-annually |

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- Definition Accumulated other comprehensive income (loss) cumulative changes in net gain (loss) from net investment hedges net of tax. + References No definition available. + Details
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- Definition Derivative instruments frequency of cash settlements. + References No definition available. + Details
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- Definition The amount of cash received during the period on settlement of a hedge. + References No definition available. + Details
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