Loans and Related Allowance for Credit Losses, Commercial Loan Categories by Delinquency Status (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	$ 909,711	$ 936,682	$ 942,424
Total nonaccrual loans	8,172	8,256
Total Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	530,642	547,427
Total nonaccrual loans	4,952	4,914
Total Commercial [Member] | Current-29 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	523,187	540,997
Total Commercial [Member] | 30-89 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	1,972	1,328
Total Commercial [Member] | 90 days or more past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans	531	188
Total Commercial [Member] | Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	372,750	380,388
Nonaccrual loans	743	662
Total Commercial [Member] | Commercial and industrial loans [Member] | Current-29 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	370,641	379,099
Total Commercial [Member] | Commercial and industrial loans [Member] | 30-89 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,097	584
Total Commercial [Member] | Commercial and industrial loans [Member] | 90 days or more past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	269	43
Total Commercial [Member] | Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	141,410	150,616
Nonaccrual loans	4,115	4,188
Total Commercial [Member] | Commercial real estate [Member] | Current-29 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	136,362	145,721
Total Commercial [Member] | Commercial real estate [Member] | 30-89 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	671	562
Total Commercial [Member] | Commercial real estate [Member] | 90 days or more past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	262	145
Total Commercial [Member] | Lease financing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease financing	16,482	16,423
Nonaccrual lease financing	94	64
Total Commercial [Member] | Lease financing [Member] | Current-29 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease financing	16,184	16,177
Total Commercial [Member] | Lease financing [Member] | 30-89 days past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease financing	204	182
Total Commercial [Member] | Lease financing [Member] | 90 days or more past due [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease financing	$ 0	$ 0