Derivative Financial Instruments - Amounts Related to Derivative Instruments Not Designated as Hedges (Details) - Not designated as hedges - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	$ (122)	$ 79	$ 768	$ 130
Client-related and other risk management | Interest rate contracts | Investment banking and trading income and other income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	37	16	(27)	26
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	(26)	(1)	81	1
Client-related and other risk management | Equity contracts | Investment banking and trading income and other income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	3	0	(7)	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	(153)	0	306	0
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	1	0	4	0
Mortgage banking | Interest rate contracts | Residential mortgage income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	(26)	(19)	(148)	(34)
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	0	0
MSRs | Interest rate contracts | Residential mortgage income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	42	83	537	137
MSRs | Interest rate contracts | Commercial real estate related income
Derivative Instruments, Gain (Loss) [Line Items]
Pre-tax Gain (Loss) Recognized in Income	$ 2	$ 0	$ 22	$ 0