INCOME TAXES, Deferred Tax Assets/(Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Deferred tax assets:
Deferred compensation	$ 455	$ 433
Allowances for credit losses	143	140
Lease liabilities	135	123
Unrealized loss associated with available-for-sale securities	131	161
Accrued expenses	43	46
Net operating losses and credit carryforwards	30	26
Unrealized loss associated with loan portfolios	23	32
Property and equipment	3	0
Other	19	19
Total deferred tax assets	982	980
Less: valuation allowance	(9)	(9)
Total deferred tax assets, net of valuation allowance	973	971
Deferred tax liabilities:
ROU lease assets	(148)	(134)
Goodwill and identifiable intangible assets	(144)	(138)
Property and equipment	0	(44)
Other	(10)	(8)
Total deferred tax liabilities	(302)	(324)
Net deferred tax assets	671	647
Deferred income taxes, net	671	651
Other payables
Deferred tax liabilities:
Other payables	$ 0	$ (4)