Derivative Financial Instruments - Net Gains (Losses) Recorded in the Condensed Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used for Risk Management and Other Business Purposes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 46	$ 11	$ (88)	$ 361
Forward contracts related to residential mortgage loans held for sale | Mortgage banking net revenue | Residential mortgages held for sale
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(58)	47	9	(11)
Interest rate contracts | Mortgage banking net revenue | MSR portfolio
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	46	11	(88)	361
Foreign exchange contracts | Other noninterest income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(3)	(6)	(5)	8
Equity contracts | Other noninterest income | Swap
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (37)	$ (29)	$ (50)	$ (51)