COLLATERALIZED AGREEMENTS AND FINANCINGS, Schedule of Offsetting Transactions (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Reverse repurchase agreements
Gross amounts of recognized assets/liabilities	$ 302	$ 413
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	302	413
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(302)	(413)
Net amounts	0	0
Securities borrowed
Gross amounts of recognized assets/liabilities	396	336
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	396	336
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(372)	(326)
Net amounts	24	10
Gross amounts of recognized assets/liabilities	698	749
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	698	749
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(674)	(739)
Net amounts	24	10
Repurchase agreements
Gross amounts of recognized assets/liabilities	325	402
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	325	402
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(325)	(402)
Net amounts	0	0
Securities loaned
Gross amounts of recognized assets/liabilities	786	536
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	786	536
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(768)	(522)
Net amounts	18	14
Gross amounts of recognized assets/liabilities	1,111	938
Gross amounts offset on the Condensed Consolidated Statements of Financial Condition	0	0
Net amounts included in the Condensed Consolidated Statements of Financial Condition	1,111	938
Gross amounts not offset on the Condensed Consolidated Statements of Financial Condition	(1,093)	(924)
Net amounts	$ 18	$ 14