Loans and Leases - Accruing and Non-Accruing Loans by Class (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	$ 61,501	$ 61,853
Total Accruing	61,606	61,963
Current, non-accruing	380	372
Total Non- Accruing	609	602
Loans and leases	62,215	62,565
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	97	89
Past due, non-accruing	54	51
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	8	21
Past due, non-accruing	175	179
Commercial: | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	33,130	33,222
Total Accruing	33,159	33,255
Current, non-accruing	116	101
Total Non- Accruing	195	173
Loans and leases	33,354	33,428
Commercial: | Commercial, financial, and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	28	32
Past due, non-accruing	12	26
Commercial: | Commercial, financial, and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	1	1
Past due, non-accruing	67	46
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,139	14,421
Commercial: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	168	174
Consumer:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,089	14,047
Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,900	13,845
Total Accruing	13,960	13,914
Current, non-accruing	48	50
Total Non- Accruing	129	133
Loans and leases	14,089	14,047
Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	53	50
Past due, non-accruing	17	14
Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	7	19
Past due, non-accruing	64	69
Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	625	662
Total Accruing	632	667
Current, non-accruing	0	0
Total Non- Accruing	1	2
Loans and leases	633	669
Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	7	4
Past due, non-accruing	1	1
Consumer: | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	1
Past due, non-accruing	0	1
C&I | Commercial: | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	29,764	29,751
Total Accruing	29,790	29,784
Current, non-accruing	116	101
Total Non- Accruing	195	173
Loans and leases	29,985	29,957
Nonaccrual, no allowance	185	172
C&I | Commercial: | Commercial, financial, and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	25	32
Past due, non-accruing	12	26
C&I | Commercial: | Commercial, financial, and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	1	1
Past due, non-accruing	67	46
Loans to mortgage companies | Commercial: | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	3,366	3,471
Total Accruing	3,369	3,471
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	3,369	3,471
Loans to mortgage companies | Commercial: | Commercial, financial, and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	0
Past due, non-accruing	0	0
Loans to mortgage companies | Commercial: | Commercial, financial, and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	0	0
Commercial Real Estate | Commercial: | Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual, no allowance	278	287
Commercial Real Estate | Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,139	14,421
Commercial Real Estate | Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,846	14,124
Total Accruing	13,855	14,127
Current, non-accruing	216	221
Total Non- Accruing	284	294
Loans and leases	14,139	14,421
Commercial Real Estate | Commercial real estate | Commercial real estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	9	3
Past due, non-accruing	24	10
Commercial Real Estate | Commercial real estate | Commercial real estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	44	63
HELOC | Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,050	2,045
Total Accruing	2,064	2,058
Current, non-accruing	18	19
Total Non- Accruing	31	34
Loans and leases	2,095	2,092
Nonaccrual, no allowance	3	3
HELOC | Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	11	11
Past due, non-accruing	3	4
HELOC | Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	2
Past due, non-accruing	10	11
R E Installment Loans | Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	11,850	11,800
Total Accruing	11,896	11,856
Current, non-accruing	30	31
Total Non- Accruing	98	99
Loans and leases	11,994	11,955
Nonaccrual, no allowance	8	9
R E Installment Loans | Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	42	39
Past due, non-accruing	14	10
R E Installment Loans | Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	17
Past due, non-accruing	54	58
Credit card | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	249	262
Total Accruing	253	265
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	253	265
Credit card | Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	2
Past due, non-accruing	0	0
Credit card | Consumer: | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	1
Past due, non-accruing	0	0
Other | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	376	400
Total Accruing	379	402
Current, non-accruing	0	0
Total Non- Accruing	1	2
Loans and leases	380	404
Other | Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	2
Past due, non-accruing	1	1
Other | Consumer: | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	$ 0	$ 1