REVENUES, Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Principal transactions	$ 147	$ 97
Noninterest Income	2,057	1,763
All other	40	11
Interest income	203	297
Total revenues	2,260	2,060
Interest expense	(38)	(51)
Net revenues	2,222	2,009
Receivables related to contracts with customers	299		$ 342
Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	1,067	955
Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	528	460
Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	381	363
Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	151	148
Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	98	101
Equities, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	132	114
Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	145	178
Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	94	90
RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	21	58
Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	30	30
Total investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	261	141
Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	149	60
Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	66	50
Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	46	31
Total other
Disaggregation of Revenue [Line Items]
Noninterest Income	56	29
Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	16	18
Operating segments | Private Client Group
Disaggregation of Revenue [Line Items]
Principal transactions	12	17
Noninterest Income	1,439	1,373
All other	5	9
Interest income	30	49
Total revenues	1,469	1,422
Interest expense	(2)	(8)
Net revenues	1,467	1,414
Operating segments | Private Client Group | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	885	782
Operating segments | Private Client Group | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	353	347
Operating segments | Private Client Group | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	341	330
Operating segments | Private Client Group | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	148	144
Operating segments | Private Client Group | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	98	101
Operating segments | Private Client Group | Equities, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	95	85
Operating segments | Private Client Group | Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	190	224
Operating segments | Private Client Group | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	94	90
Operating segments | Private Client Group | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	64	105
Operating segments | Private Client Group | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	32	29
Operating segments | Private Client Group | Total investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	6	11
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	6	11
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	5	9
Operating segments | Private Client Group | Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Capital Markets
Disaggregation of Revenue [Line Items]
Principal transactions	134	82
Noninterest Income	451	266
All other	3	0
Interest income	3	8
Total revenues	454	274
Interest expense	(2)	(6)
Net revenues	452	268
Operating segments | Capital Markets | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	2
Operating segments | Capital Markets | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	173	115
Operating segments | Capital Markets | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	39	33
Operating segments | Capital Markets | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	3
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, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	37	30
Operating segments | Capital Markets | Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	1
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	0	0
Operating segments | Capital Markets | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	1
Operating segments | Capital Markets | Total investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	255	130
Operating segments | Capital Markets | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	149	60
Operating segments | Capital Markets | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	60	39
Operating segments | Capital Markets | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	46	31
Operating segments | Capital Markets | Total other
Disaggregation of Revenue [Line Items]
Noninterest Income	19	18
Operating segments | Capital Markets | Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	16	18
Operating segments | Asset Management
Disaggregation of Revenue [Line Items]
Principal transactions	0	0
Noninterest Income	195	183
All other	1	0
Interest income	0	1
Total revenues	195	184
Interest expense	0	0
Net revenues	195	184
Operating segments | Asset Management | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	188	176
Operating segments | Asset Management | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	2	2
Operating segments | Asset Management | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	2
Operating segments | Asset Management | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	2	2
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, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | Asset Management | Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	4	5
Operating segments | Asset Management | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	1
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	4	4
Operating segments | Asset Management | Total 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	1	0
Operating segments | Asset Management | Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank
Disaggregation of Revenue [Line Items]
Principal transactions	1	0
Noninterest Income	10	6
All other	9	6
Interest income	168	231
Total revenues	178	237
Interest expense	(11)	(21)
Net revenues	167	216
Operating segments | RJ Bank | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	1	0
Operating segments | RJ Bank | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Equities, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Total investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Operating segments | RJ Bank | Total other
Disaggregation of Revenue [Line Items]
Noninterest Income	9	6
Operating segments | RJ Bank | Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations
Disaggregation of Revenue [Line Items]
Principal transactions	0	(2)
Noninterest Income	(38)	(65)
All other	22	(4)
Interest income	2	8
Total revenues	(36)	(57)
Interest expense	(23)	(16)
Net revenues	(59)	(73)
Other and intersegment eliminations | Other and intersegment eliminations | Asset management and related administrative fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(8)	(5)
Other and intersegment eliminations | Other and intersegment eliminations | Total brokerage revenues
Disaggregation of Revenue [Line Items]
Noninterest Income	(1)	(4)
Other and intersegment eliminations | Other and intersegment eliminations | Subtotal securities commissions
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(1)	(2)
Other and intersegment eliminations | Other and intersegment eliminations | Mutual and other fund products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(1)	(1)
Other and intersegment eliminations | Other and intersegment eliminations | Insurance and annuity products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations | Equities, ETFs and fixed income products
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	(1)
Other and intersegment eliminations | Other and intersegment eliminations | Total account and service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(51)	(52)
Other and intersegment eliminations | Other and intersegment eliminations | Mutual fund and annuity service fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	(1)
Other and intersegment eliminations | Other and intersegment eliminations | RJBDP fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(43)	(47)
Other and intersegment eliminations | Other and intersegment eliminations | Client account and other fees
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	(8)	(4)
Other and intersegment eliminations | Other and intersegment eliminations | Total investment banking
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations | Merger & acquisition and advisory
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations | Equity underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations | Debt underwriting
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	0	0
Other and intersegment eliminations | Other and intersegment eliminations | Total other
Disaggregation of Revenue [Line Items]
Noninterest Income	22	(4)
Other and intersegment eliminations | Other and intersegment eliminations | Tax credit fund revenues
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 0	$ 0