DERIVATIVE ASSETS AND DERIVATIVE LIABILITIES, Income Statement Location (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Principal transactions/other revenues | Interest rate
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative liability	$ 0	$ 0	$ 5	$ 2
Other revenues | Foreign exchange
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative liability	43	(4)	32	22
Compensation, commissions and benefits expense | Deutsche Bank Restricted Stock Derivative
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of derivative liability	$ (1)	$ 0	$ (1)	$ 5