COMMITMENTS, CONTINGENCIES AND GUARANTEES, Summary of Off-Balance Sheet Risks (Details) - USD ($) $ in Millions	Jun. 30, 2024	Sep. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
SBL and other consumer lines of credit	$ 42,523	$ 38,791
Commercial lines of credit	4,436	4,131
Unfunded lending commitments	672	936
Standby letters of credit	$ 106	$ 123