FAIR VALUE, Investments in Private Equity Measured at Net Asset Value Per Share (Details) - Private equity investments - Recurring - USD ($) $ in Millions	Dec. 31, 2020	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Private equity investments measured at NAV	$ 85	$ 79
Private equity investments not measured at NAV	52	37
Total private equity investments	137	116
Total equity attributable to Raymond James Financial, Inc.
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Unfunded commitment	9	9
Total private equity investments	102	90
Noncontrolling interests
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis [Line Items]
Total private equity investments	$ 35	$ 26