FAIR VALUE, Carrying Amounts and Estimated Fair Value of Financial Instruments not Recorded on Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2026	Sep. 30, 2025
Carrying amount
Financial assets:
Bank loans, net	$ 54,662	$ 51,345
Financial liabilities:
Bank deposits - certificates of deposit	2,320	1,937
Senior notes payable	3,521	3,520
Recurring \| Total estimated fair value
Financial assets:
Bank loans, net	54,366	50,748
Financial liabilities:
Bank deposits - certificates of deposit	2,320	1,943
Senior notes payable	3,187	3,299
Recurring \| Level 2 \| Total estimated fair value
Financial assets:
Bank loans, net	193	386
Financial liabilities:
Bank deposits - certificates of deposit	2,320	1,943
Senior notes payable	3,187	3,299
Recurring \| Level 3 \| Total estimated fair value
Financial assets:
Bank loans, net	54,173	50,362
Financial liabilities:
Bank deposits - certificates of deposit	0	0
Senior notes payable	$ 0	$ 0

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Name:	us-gaap_DebtInstrumentFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant