Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	Jun. 30, 2026	Sep. 30, 2025
Variable Interest Entity [Line Items]
Assets	$ 10,727	$ 9,829
Liabilities	9,641	9,072
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Assets	61	65
Liabilities	$ 2	$ 2

Amount of asset recognized for present right to economic benefit.

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- Definition

Amount of liability recognized for present obligation requiring transfer or otherwise providing economic benefit to others.

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