Loans and Related Allowance for Credit Losses, 90 Days or More Past Due and Still Accruing (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	$ 4,139	$ 3,751
Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	1,450	1,105
Government insured or guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	2,689	2,646
Total Commercial [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	531	188
Total Commercial [Member] | Commercial and industrial loans [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	269	43
Total Commercial [Member] | Commercial real estate [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	262	145
Total Consumer [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	919	917
Total Consumer [Member] | Residential mortgage [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	28	31
Total Consumer [Member] | Credit card [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	785	743
Total Consumer [Member] | Auto [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	71	101
Total Consumer [Member] | Other consumer [Member] | Not government insured/guaranteed [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, 90 days or more past due and still accruing	$ 35	$ 42