Goodwill and Mortgage Servicing Rights - Mortgage Fees and Related Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Risk management:
Mortgage fees and related income	$ 551	$ 917	$ 1,255	$ 1,237
All other	3	0	4	0
Consumer & Community Banking
CCB mortgage fees and related income
Production revenue	517	742	1,274	1,061
Operating revenue:
Loan servicing revenue	316	343	564	682
Changes in MSR asset fair value due to collection/realization of expected cash flows	(182)	(247)	(369)	(495)
Total operating revenue	134	96	195	187
Risk management:
Changes in MSR asset fair value due to market interest rates and other	(500)	(144)	336	(1,514)
Other changes in MSR asset fair value due to other inputs and assumptions in model	(28)	33	(67)	21
Changes in derivative fair value and other	425	190	(487)	1,482
Total risk management	(103)	79	(218)	(11)
Total net mortgage servicing revenue	31	175	(23)	176
Mortgage fees and related income	$ 548	$ 917	$ 1,251	$ 1,237