Sales of Receivables and Servicing Rights - Activity Related to the MSR Portfolio (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Transfers and Servicing of Financial Assets [Abstract]
Securities gains (losses), net -non-qualifying hedges on MSRs	[1]	$ 2	$ 3	$ (15)
Changes in fair value and settlement of free-standing derivatives purchased to economically hedge the MSR portfolio		307	221	(21)
MSR fair value adjustments due to changes in inputs or assumptions		$ (311)	$ (203)	$ 42

[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.