Premises, Equipment and Leases - Operating Lease Portfolio (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment and Lease Commitments [Abstract]
Right-of-use assets	$ 1,137	$ 1,316
Lease liabilities	$ 1,485	$ 1,688
Weighted-average remaining lease term	8 years	8 years 8 months 12 days
Weighted-average discount rate	3.00%	3.10%
Operating lease cost	$ 305	$ 315
Variable lease cost	42	43
Total lease cost	347	358
Sublease income	(23)	(26)
Net lease cost	324	332
Cash paid for amounts included in the measurement of lease liabilities	353	325
Right-of-use assets obtained in exchange for lease liabilities	$ 81	$ 180
Operating Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities
Operating lease, right of use asset, statement of financial position, extensible enumeration	Other assets	Other assets