Loans and Related Allowance for Credit Losses, Payment Performance of Commercial Loan Modifications (Details) - Total Commercial [Member] $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	$ 209
Charge-offs	10
Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	205
Current-29 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	185
30-89 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	20
90 days or more past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	0
Commercial and industrial loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	137
Charge-offs	10
Commercial and industrial loans [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	134
Commercial and industrial loans [Member] | Current-29 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	115
Commercial and industrial loans [Member] | 30-89 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	19
Commercial and industrial loans [Member] | 90 days or more past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	0
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	72
Charge-offs	0
Commercial real estate [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	71
Commercial real estate [Member] | Current-29 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	70
Commercial real estate [Member] | 30-89 days past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	1
Commercial real estate [Member] | 90 days or more past due [Member] | Excluding Modifications in Payment Deferral Period Member [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans modified during the period	$ 0