SEGMENT INFORMATION, Information Concerning Operations (Details) $ in Millions	1 Months Ended	3 Months Ended		6 Months Ended
	Dec. 31, 2020 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) businessSegment	Mar. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)
Segment Reporting Information [Line Items]
Number of operating segments | businessSegment				5
Revenues:
Total net revenues		$ 2,372	$ 2,068	$ 4,594	$ 4,077
Pre-tax income
Total pre-tax income		447	239	846	598
Net interest income (expense):
Net interest income		163	242	328	488
Total assets:
Total assets		56,066		56,066		$ 47,482
Goodwill:
Goodwill		636		636		466
NWPS
Goodwill:
Goodwill, acquired during period	$ 139
Operating segments | Private Client Group
Revenues:
Total net revenues		1,647	1,495	3,114	2,909
Pre-tax income
Total pre-tax income		192	170	332	323
Net interest income (expense):
Net interest income		27	38	55	79
Total assets:
Total assets		18,338		18,338		12,574
Goodwill:
Goodwill		417		417		277
Operating segments | Capital Markets
Revenues:
Total net revenues		433	290	885	558
Pre-tax income
Total pre-tax income		105	28	234	57
Net interest income (expense):
Net interest income		3	4	4	6
Total assets:
Total assets		2,334		2,334		2,336
Goodwill:
Goodwill		150		150		120
Operating segments | Asset Management
Revenues:
Total net revenues		209	184	404	368
Pre-tax income
Total pre-tax income		87	73	170	146
Net interest income (expense):
Net interest income		0	0	0	1
Total assets:
Total assets		369		369		380
Goodwill:
Goodwill		69		69		69
Operating segments | RJ Bank
Revenues:
Total net revenues		160	210	327	426
Pre-tax income
Total pre-tax income		111	14	182	149
Net interest income (expense):
Net interest income		155	205	312	415
Total assets:
Total assets		33,010		33,010		30,356
Operating segments | Other
Revenues:
Total net revenues		(12)	(44)	(8)	(52)
Pre-tax income
Total pre-tax income		(48)	(46)	(72)	(77)
Net interest income (expense):
Net interest income		(22)	(5)	(43)	(13)
Total assets:
Total assets		2,015		2,015		$ 1,836
Intersegment eliminations
Revenues:
Total net revenues		$ (65)	$ (67)	$ (128)	$ (132)