DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Derivative Assets and Liability Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2023	Sep. 30, 2022
Derivative assets
Derivative assets	$ 370	$ 536
Counterparty netting	(36)	(35)
Cash collateral netting	(243)	(313)
Total amounts offset	(279)	(348)
Derivative assets	91	188
Financial instruments	(14)	(60)
Net amount	77	128
Derivative liabilities
Derivative liabilities	429	595
Counterparty netting	(36)	(35)
Cash collateral netting	(42)	(30)
Total amounts offset	(78)	(65)
Net amounts presented on the Condensed Consolidated Statements of Financial Condition	351	530
Financial instruments	(8)	(52)
Net amount	343	478
Notional amount	20,733	19,618
Derivatives not designated as hedging instruments
Derivative assets
Derivative assets	361	518
Derivative liabilities
Derivative liabilities	423	595
Notional amount	18,284	17,476
Derivatives not designated as hedging instruments | Interest rate - other
Derivative assets
Derivative assets	353	462
Derivative liabilities
Derivative liabilities	407	535
Notional amount	16,404	14,647
Derivatives not designated as hedging instruments | Interest rate - matched book
Derivative assets
Interest rate - matched book	8	52
Derivative liabilities
Interest rate - matched book	8	52
Notional amount	170	1,340
Derivatives not designated as hedging instruments | Foreign exchange
Derivative assets
Derivative assets	0	4
Derivative liabilities
Derivative liabilities	4	5
Notional amount	1,128	958
Derivatives not designated as hedging instruments | Other
Derivative assets
Derivative assets	0	0
Derivative liabilities
Derivative liabilities	4	3
Notional amount	582	531
Derivatives designated as hedging instruments
Derivative assets
Derivative assets	9	18
Derivative liabilities
Derivative liabilities	6	0
Notional amount	2,449	2,142
Derivatives designated as hedging instruments | Interest rate - other
Derivative assets
Derivative assets	9	12
Derivative liabilities
Derivative liabilities	1	0
Notional amount	1,300	1,050
Derivatives designated as hedging instruments | Foreign exchange
Derivative assets
Derivative assets	0	6
Derivative liabilities
Derivative liabilities	5	0
Notional amount	$ 1,149	$ 1,092