Mortgage Banking Activities, Mortgage Banking Noninterest Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Servicing fees:
Contractually specified servicing fees	$ 846	$ 901	$ 1,686	$ 1,817
Late charges	30	42	63	86
Ancillary fees	38	47	76	87
Unreimbursed direct servicing costs	(84)	(85)	(154)	(179)
Net servicing fees	830	905	1,671	1,811
Changes in fair value of MSRs carried at fair value:
Due to changes in valuation model inputs or assumptions	(1,078)	345	(1,969)	1,675
Changes due to collection/realization of expected cash flows over time	(561)	(460)	(1,043)	(943)
Total changes in fair value of MSRs carried at fair value	(1,639)	(115)	(3,012)	732
Amortization	(69)	(65)	(135)	(130)
Net Derivative Gains (Losses) From Economic Hedges Related To Mortgage Servicing Activities	1,155	(319)	2,117	(1,539)
Total servicing income, net	277	406	641	874
Net gains on mortgage loan origination/sales activities (4)	481	364	825	830
Total mortgage banking noninterest income	758	770	1,466	1,704
Market-related valuation changes to MSRs, net of hedge results	77	26	148	136
Net Derivative Gains (Losses) From Economic Hedges Related To Mortgage Loans Held for Sale and Derivative Loan Commitments	$ (283)	$ 134	$ (434)	$ 759