Goodwill and Mortgage Servicing Rights - Mortgage Fees and Related Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Risk management:
All other	$ 1	$ 0
Mortgage fees and related income	704	320
Consumer & Community Banking
CCB mortgage fees and related income
Production revenue	757	319
Operating revenue:
Loan servicing revenue	248	339
Changes in MSR asset fair value due to collection/realization of expected cash flows	(187)	(248)
Total operating revenue	61	91
Risk management:
Changes in MSR asset fair value due to market interest rates and other	836	(1,370)
Other changes in MSR asset fair value due to other inputs and assumptions in model	(39)	(12)
Changes in derivative fair value and other	(912)	1,292
Total risk management	(115)	(90)
Total net mortgage servicing revenue	(54)	1
Mortgage fees and related income	$ 703	$ 320