GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS, NET, Schedule of Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Goodwill [Roll Forward]
Goodwill as of beginning of year	$ 1,437	$ 1,422
Foreign currency translations	14	15
Goodwill as of end of year	1,451	1,437
Private Client Group
Goodwill [Roll Forward]
Goodwill as of beginning of year	564	550
Foreign currency translations	14	14
Goodwill as of end of year	578	564
Capital Markets
Goodwill [Roll Forward]
Goodwill as of beginning of year	275	274
Foreign currency translations	0	1
Goodwill as of end of year	275	275
Asset Management
Goodwill [Roll Forward]
Goodwill as of beginning of year	69	69
Foreign currency translations	0	0
Goodwill as of end of year	69	69
Bank
Goodwill [Roll Forward]
Goodwill as of beginning of year	529	529
Foreign currency translations	0	0
Goodwill as of end of year	$ 529	$ 529