SEGMENT INFORMATION, Information Concerning Operations (Details) $ in Millions	3 Months Ended
	Dec. 31, 2022 USD ($) businessSegment	Dec. 31, 2021 USD ($)	Sep. 30, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | businessSegment	5
Revenues:
Total net revenues	$ 2,786	$ 2,781
Pre-tax income
Total pre-tax income	652	558
Insurance settlement	32
Net interest income (expense):
Net interest income	586	188
Total assets:
Total assets	77,047		$ 80,951
Goodwill:
Goodwill	1,435		1,422
Operating segments | Private Client Group
Revenues:
Total net revenues	2,063	1,839
Pre-tax income
Total pre-tax income	434	195
Net interest income (expense):
Net interest income	87	30
Total assets:
Total assets	13,920		17,770
Goodwill:
Goodwill	562		550
Operating segments | Capital Markets
Revenues:
Total net revenues	295	614
Pre-tax income
Total pre-tax income	(16)	201
Net interest income (expense):
Net interest income	0	3
Total assets:
Total assets	2,898		3,951
Goodwill:
Goodwill	275		274
Operating segments | Asset Management
Revenues:
Total net revenues	207	236
Pre-tax income
Total pre-tax income	80	107
Net interest income (expense):
Net interest income	2	0
Total assets:
Total assets	558		556
Goodwill:
Goodwill	69		69
Operating segments | Bank
Revenues:
Total net revenues	508	183
Pre-tax income
Total pre-tax income	136	102
Net interest income (expense):
Net interest income	491	177
Total assets:
Total assets	57,623		56,737
Goodwill:
Goodwill	529		529
Operating segments | Other
Revenues:
Total net revenues	9	(15)
Pre-tax income
Total pre-tax income	18	(47)
Net interest income (expense):
Net interest income	6	(22)
Total assets:
Total assets	2,048		$ 1,937
Intersegment eliminations
Revenues:
Total net revenues	$ (296)	$ (76)