Derivatives (Net Gains (Losses) Recorded in the Consolidated Statements of Income Relating to Free-Standing Derivative Instruments Used For Risk Management) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Interest Rate Contract | Forward Contracts | Loans Held For Sale | Mortgage banking net revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ 0	$ 0
Interest Rate Contract | Servicing Rights | Mortgage banking net revenue
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	60	(49)
Foreign Exchange Contract | Other noninterest income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	(2)	2
Equity Contract | Swap | Other noninterest income
Derivative Instruments, Gain (Loss)
Net gains (losses) recorded in earnings	$ (31)	$ (39)