MSR (Activity Related to the MSR Portfolio) (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Servicing Assets at Fair Value
Securities gains , net - non-qualifying hedges on mortgage servcing rights	$ 3	$ 3	[1]
Changes in fair value and settlement of free-standing derivatives purchased to economically hedge the MSR portfolio (Mortgage banking net revenue)	350	60
MSR fair value adjustments due to changes in inputs or assumptions	378	84
Mortgage Servicing Rights
Servicing Assets at Fair Value
MSR fair value adjustments due to changes in inputs or assumptions	$ (331)	$ (57)

[1] During the first quarter of 2020, certain noninterest income and noninterest expense line items were reclassified to better align disclosures to business activities. These reclassifications were retrospectively applied to all prior periods presented. Total noninterest income and noninterest expense did not change as a result of these reclassifications.