Goodwill and Mortgage Servicing Rights - Mortgage Fees and Related Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Risk management:
All other	$ 1	$ 2	$ 1	$ 2
Mortgage fees and related income	887	262	1,562	1,051
Consumer & Community Banking
CCB mortgage fees and related income
Net production revenue	738	108	1,291	296
Operating revenue:
Loan servicing revenue	351	435	1,172	1,389
Changes in MSR asset fair value due to collection/realization of expected cash flows	(256)	(195)	(702)	(542)
Total operating revenue	95	240	470	847
Risk management:
Changes in MSR asset fair value due to market interest rates and other	(433)	150	(1,274)	636
Other changes in MSR asset fair value due to other inputs and assumptions in model	(14)	(52)	(298)	(59)
Change in derivative fair value and other	500	(186)	1,372	(671)
Total risk management	53	(88)	(200)	(94)
Total net mortgage servicing revenue	148	152	270	753
Mortgage fees and related income	$ 886	$ 260	$ 1,561	$ 1,049