GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS, NET, Net Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Finite-lived Intangible Assets [Roll Forward]
Net identifiable intangible assets as of beginning of year	$ 222	$ 134
Additions	334	109
Amortization expense	(33)	(21)
Foreign currency translations	(14)
Net identifiable intangible assets as of end of year	509	222
Private Client Group
Finite-lived Intangible Assets [Roll Forward]
Net identifiable intangible assets as of beginning of year	120	31
Additions	85	96
Amortization expense	(13)	(7)
Foreign currency translations	(14)
Net identifiable intangible assets as of end of year	178	120
Capital Markets
Finite-lived Intangible Assets [Roll Forward]
Net identifiable intangible assets as of beginning of year	17	13
Additions	52	13
Amortization expense	(9)	(9)
Foreign currency translations	0
Net identifiable intangible assets as of end of year	60	17
Asset Management
Finite-lived Intangible Assets [Roll Forward]
Net identifiable intangible assets as of beginning of year	85	90
Additions	61	0
Amortization expense	(7)	(5)
Foreign currency translations	0
Net identifiable intangible assets as of end of year	139	85
Bank
Finite-lived Intangible Assets [Roll Forward]
Net identifiable intangible assets as of beginning of year	0	0
Additions	136	0
Amortization expense	(4)	0
Foreign currency translations	0
Net identifiable intangible assets as of end of year	$ 132	$ 0