Loans and Leases - Accruing and Non-Accruing Loans by Class (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	$ 61,774	$ 60,724
Total Accruing	61,867	60,830
Current, non-accruing	333	228
Total Non- Accruing	578	462
Loans and leases	62,445	61,292
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	76	85
Past due, non-accruing	36	30
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	17	21
Past due, non-accruing	209	204
Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	32,873	32,416
Total Accruing	32,902	32,449
Current, non-accruing	102	113
Total Non- Accruing	190	184
Loans and leases	33,092	32,633
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	24	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	64	53
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,705	14,216
Commercial: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	184	180
Consumer:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,961	13,650
Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,781	13,453
Total Accruing	13,833	13,510
Current, non-accruing	50	73
Total Non- Accruing	128	140
Loans and leases	13,961	13,650
Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	39	40
Past due, non-accruing	12	12
Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	13	17
Past due, non-accruing	66	55
Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	679	783
Total Accruing	686	791
Current, non-accruing	0	1
Total Non- Accruing	1	2
Loans and leases	687	793
Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	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	3	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	29,629	30,398
Total Accruing	29,658	30,430
Current, non-accruing	102	108
Total Non- Accruing	190	179
Loans and leases	29,848	30,609
Nonaccrual, no allowance	175	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	28	31
Past due, non-accruing	24	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	64	53
Loans to mortgage companies | Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	3,244	2,018
Total Accruing	3,244	2,019
Current, non-accruing	0	5
Total Non- Accruing	0	5
Loans and leases	3,244	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	253	129
Commercial Real Estate | Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,705	14,216
Commercial Real Estate | Commercial real estate | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	14,441	14,072
Total Accruing	14,446	14,080
Current, non-accruing	181	41
Total Non- Accruing	259	136
Loans and leases	14,705	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	5	8
Past due, non-accruing	0	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	78	95
Home Equity Line of Credit | Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,038	2,158
Total Accruing	2,051	2,173
Current, non-accruing	20	30
Total Non- Accruing	34	46
Loans and leases	2,085	2,219
Nonaccrual, no allowance	3	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	10	11
Past due, non-accruing	5	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	11,743	11,295
Total Accruing	11,782	11,337
Current, non-accruing	30	43
Total Non- Accruing	94	94
Loans and leases	11,876	11,431
Nonaccrual, no allowance	9	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	29	29
Past due, non-accruing	7	6
R E Installment Loans | Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	10	13
Past due, non-accruing	57	45
Credit card | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	268	271
Total Accruing	273	277
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	273	277
Credit card | Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	2	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	3	3
Past due, non-accruing	0	0
Other | Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	411	512
Total Accruing	413	514
Current, non-accruing	0	1
Total Non- Accruing	1	2
Loans and leases	414	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