Loans and Leases - Accruing and Non-Accruing Loans by Class (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	$ 62,110	$ 60,724
Total Accruing	62,207	60,830
Current, non-accruing	292	228
Total Non- Accruing	574	462
Loans and leases	62,781	61,292
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	91	85
Past due, non-accruing	49	30
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	6	21
Past due, non-accruing	233	204
Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	33,252	32,416
Total Accruing	33,285	32,449
Current, non-accruing	87	113
Total Non- Accruing	167	184
Loans and leases	33,452	32,633
Commercial: | Commercial, financial and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	32	32
Past due, non-accruing	3	18
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	77	53
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,669	14,216
Commercial: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	190	180
Consumer:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,909	13,650
Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,713	13,453
Total Accruing	13,765	13,510
Current, non-accruing	67	73
Total Non- Accruing	144	140
Loans and leases	13,909	13,650
Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	49	40
Past due, non-accruing	17	12
Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	17
Past due, non-accruing	60	55
Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	741	783
Total Accruing	749	791
Current, non-accruing	1	1
Total Non- Accruing	2	2
Loans and leases	751	793
Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	6	5
Past due, non-accruing	0	0
Consumer: | Credit Card and Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	2	3
Past due, non-accruing	1	1
General C I | Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	30,318	30,398
Total Accruing	30,351	30,430
Current, non-accruing	87	108
Total Non- Accruing	167	179
Loans and leases	30,518	30,609
Nonaccrual, no allowance	158	178
General C I | Commercial: | Commercial, financial and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	32	31
Past due, non-accruing	3	18
General 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	77	53
Loans to mortgage companies | Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,934	2,018
Total Accruing	2,934	2,019
Current, non-accruing	0	5
Total Non- Accruing	0	5
Loans and leases	2,934	2,024
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	0	1
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	255	129
Commercial Real Estate | Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,669	14,216
Commercial Real Estate | Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	14,404	14,072
Total Accruing	14,408	14,080
Current, non-accruing	137	41
Total Non- Accruing	261	136
Loans and leases	14,669	14,216
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	4	8
Past due, non-accruing	29	0
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	95	95
Home Equity Line of Credit | Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,068	2,158
Total Accruing	2,080	2,173
Current, non-accruing	29	30
Total Non- Accruing	42	46
Loans and leases	2,122	2,219
Nonaccrual, no allowance	4	4
Home Equity Line of Credit | Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	9	11
Past due, non-accruing	4	6
Home Equity Line of Credit | Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	4
Past due, non-accruing	9	10
R E Installment Loans | Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	11,645	11,295
Total Accruing	11,685	11,337
Current, non-accruing	38	43
Total Non- Accruing	102	94
Loans and leases	11,787	11,431
Nonaccrual, no allowance	10	10
R E Installment Loans | Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	40	29
Past due, non-accruing	13	6
R E Installment Loans | Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	13
Past due, non-accruing	51	45
Credit card | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	276	271
Total Accruing	282	277
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	282	277
Credit card | Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	3
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	2	3
Past due, non-accruing	0	0
Other | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	465	512
Total Accruing	467	514
Current, non-accruing	1	1
Total Non- Accruing	2	2
Loans and leases	469	516
Other | Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	2	2
Past due, non-accruing	0	0
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	$ 1	$ 1