REVENUES (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Principal transactions	$ 139	$ 132
All other	15	20
Total non-interest revenues	2,467	2,200
Interest income	1,053	827
Total revenues	3,520	3,027
Interest expense	(507)	(241)
Net revenues	3,013	2,786
Receivables related to contracts with customers	481		$ 519
Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,407	1,242
Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	383	352
Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	137	130
Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	125	104
Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	121	118
Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	522	484
Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	319	289
Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	106	98
RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	152	137
Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	61	54
Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	181	141
Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	118	102
Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	37	23
Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	26	16
Total other
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	38	44
Noninterest income	38	44
Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	23	24
Operating segments | Private Client Group
Disaggregation of Revenue [Line Items]
Principal transactions	32	28
All other	4	6
Total non-interest revenues	2,134	1,976
Interest income	118	109
Total revenues	2,252	2,085
Interest expense	(26)	(22)
Net revenues	2,226	2,063
Operating segments | Private Client Group | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,191	1,053
Operating segments | Private Client Group | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	350	317
Operating segments | Private Client Group | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	136	128
Operating segments | Private Client Group | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	125	104
Operating segments | Private Client Group | Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	89	85
Operating segments | Private Client Group | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	382	345
Operating segments | Private Client Group | Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	546	563
Operating segments | Private Client Group | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	106	98
Operating segments | Private Client Group | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	375	405
Operating segments | Private Client Group | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	65	60
Operating segments | Private Client Group | Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	11	9
Operating segments | Private Client Group | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Private Client Group | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	11	9
Operating segments | Private Client Group | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Private Client Group | Total other
Disaggregation of Revenue [Line Items]
Noninterest income	4	6
Operating segments | Private Client Group | Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Capital Markets
Disaggregation of Revenue [Line Items]
Principal transactions	105	100
All other	1	0
Total non-interest revenues	337	295
Interest income	23	23
Total revenues	360	318
Interest expense	(22)	(23)
Net revenues	338	295
Operating segments | Capital Markets | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	1
Operating segments | Capital Markets | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	35	34
Operating segments | Capital Markets | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	1
Operating segments | Capital Markets | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Capital Markets | Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	33	33
Operating segments | Capital Markets | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	140	134
Operating segments | Capital Markets | Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	3	3
Operating segments | Capital Markets | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Capital Markets | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1	1
Operating segments | Capital Markets | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	2
Operating segments | Capital Markets | Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	170	133
Operating segments | Capital Markets | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	118	102
Operating segments | Capital Markets | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	26	15
Operating segments | Capital Markets | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	26	16
Operating segments | Capital Markets | Total other
Disaggregation of Revenue [Line Items]
Noninterest income	24	24
Operating segments | Capital Markets | Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	23	24
Operating segments | Asset Management
Disaggregation of Revenue [Line Items]
Principal transactions	0	0
All other	0	2
Total non-interest revenues	232	205
Interest income	3	2
Total revenues	235	207
Interest expense	0	0
Net revenues	235	207
Operating segments | Asset Management | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	224	197
Operating segments | Asset Management | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	1
Operating segments | Asset Management | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	1
Operating segments | Asset Management | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	2	1
Operating segments | Asset Management | Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	6	5
Operating segments | Asset Management | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1	0
Operating segments | Asset Management | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	5	5
Operating segments | Asset Management | Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Total other
Disaggregation of Revenue [Line Items]
Noninterest income	0	2
Operating segments | Asset Management | Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank
Disaggregation of Revenue [Line Items]
Principal transactions	2	4
All other	13	13
Total non-interest revenues	15	17
Interest income	872	676
Total revenues	887	693
Interest expense	(446)	(185)
Net revenues	441	508
Operating segments | Bank | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	2	4
Operating segments | Bank | Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Bank | Total other
Disaggregation of Revenue [Line Items]
Noninterest income	13	13
Operating segments | Bank | Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations
Disaggregation of Revenue [Line Items]
Principal transactions	0	0
All other	(3)	(1)
Total non-interest revenues	(251)	(293)
Interest income	37	17
Total revenues	(214)	(276)
Interest expense	(13)	(11)
Net revenues	(227)	(287)
Other and intersegment eliminations | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(8)	(9)
Other and intersegment eliminations | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(4)	0
Other and intersegment eliminations | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(3)	0
Other and intersegment eliminations | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Equities, exchange traded funds (“ETFs”) and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(1)	0
Other and intersegment eliminations | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Total brokerage revenues	(4)	0
Other and intersegment eliminations | Account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(236)	(282)
Other and intersegment eliminations | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(1)	0
Other and intersegment eliminations | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(224)	(269)
Other and intersegment eliminations | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(11)	(13)
Other and intersegment eliminations | Investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	(1)
Other and intersegment eliminations | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	(1)
Other and intersegment eliminations | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Total other
Disaggregation of Revenue [Line Items]
Noninterest income	(3)	(1)
Other and intersegment eliminations | Affordable housing investments business revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 0	$ 0