COLLATERALIZED AGREEMENTS AND FINANCINGS, Collateral (Details) - USD ($) $ in Millions	Jun. 30, 2023	Sep. 30, 2022
Collateral Received that Can be Resold or Repledged [Abstract]
Collateral we received that was available to be delivered or repledged	$ 3,099	$ 3,812
Collateral that we delivered or repledged	$ 776	$ 947

Fair value of the collateral, or portion thereof, that has been re-pledged, delivered, or otherwise used.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 860
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481420/860-30-50-1A

Name:	us-gaap_FairValueOfSecuritiesReceivedAsCollateralThatHaveBeenResoldOrRepledged
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant