FAIR VALUE, Investments in Private Equity Measured at Net Asset Value Per Share (Details) - Other investments - Recurring - USD ($) $ in Millions	Mar. 31, 2020	Sep. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Private equity investments at NAV	$ 71	$ 83
Private equity investments not measured at net asset value (NAV)	30	63
Total private equity investments	101	146
Total equity attributable to Raymond James Financial, Inc.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unfunded commitment	12	15
Total private equity investments	79	99
Noncontrolling interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total private equity investments	$ 22	$ 47