Derivative Financial Instruments - Amounts Related to Derivative Instruments Not Designated as Hedges (Details) - Not designated as hedges - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	$ 890	$ 51
Client-related and other risk management | Interest rate contracts | Investment banking and trading income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	(64)	10
Client-related and other risk management | Foreign exchange contracts | Investment banking and trading income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	107	2
Client-related and other risk management | Equity contracts | Investment banking and trading income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	(10)	0
Client-related and other risk management | Credit Contract | Investment banking and trading income and other income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income		0
Client-related and other risk management | Credit Contract | Investment banking and trading income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	459
Client-related and other risk management | Commodity Contract | Investment banking and trading income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	3	0
Mortgage banking | Interest rate contracts | Residential mortgage income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	(122)	(15)
Mortgage banking | Interest rate contracts | Commercial real estate related income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	2	0
MSRs | Interest rate contracts | Residential mortgage income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	495	54
MSRs | Interest rate contracts | Commercial real estate related income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	$ 20	$ 0