DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Derivative Assets and Liability Fair Value (Details) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Derivative assets
Derivative assets	$ 428	$ 536
Counterparty netting	(24)	(35)
Cash collateral netting	(175)	(313)
Total amounts offset	(199)	(348)
Derivative assets	229	188
Financial instruments	(108)	(60)
Net amount	121	128
Derivative liabilities
Derivative liabilities	473	595
Counterparty netting	(24)	(35)
Cash collateral netting	(56)	(30)
Total amounts offset	(80)	(65)
Net amounts presented on the Condensed Consolidated Statements of Financial Condition	393	530
Financial instruments	0	(52)
Net amount	393	478
Notional amount	22,077	19,618
Derivatives not designated as hedging instruments
Derivative assets
Derivative assets	416	518
Derivative liabilities
Derivative liabilities	473	595
Notional amount	19,639	17,476
Derivatives not designated as hedging instruments | Interest rate - other
Derivative assets
Derivative assets	414	462
Derivative liabilities
Derivative liabilities	469	535
Notional amount	17,811	14,647
Derivatives not designated as hedging instruments | Interest rate - matched book
Derivative assets
Interest rate - matched book	0	52
Derivative liabilities
Interest rate - matched book	0	52
Notional amount	0	1,340
Derivatives not designated as hedging instruments | Foreign exchange
Derivative assets
Derivative assets	2	4
Derivative liabilities
Derivative liabilities	0	5
Notional amount	1,167	958
Derivatives not designated as hedging instruments | Other
Derivative assets
Derivative assets	0	0
Derivative liabilities
Derivative liabilities	4	3
Notional amount	661	531
Derivatives designated as hedging instruments
Derivative assets
Derivative assets	12	18
Derivative liabilities
Derivative liabilities	0	0
Notional amount	2,438	2,142
Derivatives designated as hedging instruments | Interest rate - other
Derivative assets
Derivative assets	9	12
Derivative liabilities
Derivative liabilities	0	0
Notional amount	1,250	1,050
Derivatives designated as hedging instruments | Foreign exchange
Derivative assets
Derivative assets	3	6
Derivative liabilities
Derivative liabilities	0	0
Notional amount	$ 1,188	$ 1,092