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
	Mar. 31, 2021	Mar. 31, 2020
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (134)	$ 350
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	67	(58)
Interest rate contracts | Mortgage banking net revenue | MSR portfolio
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(134)	350
Foreign exchange contracts | Other noninterest income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(2)	13
Equity contracts | Other noninterest income | Swap
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (13)	$ (22)