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, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 11	$ 117	$ 361	$ 177
Interest rate contracts | Mortgage banking net revenue | Forward contracts | Residential mortgages held for sale
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	47	(5)	(11)	(5)
Interest rate contracts | Mortgage banking net revenue | MSR portfolio
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	11	117	361	177
Foreign exchange contracts | Other noninterest income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(6)	(3)	8	(5)
Equity contracts | Other noninterest income | Swap
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (29)	$ (22)	$ (51)	$ (52)