Loans and Leases - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	$ 61,292	$ 57,648
Total Accruing	61,384	57,786
Current, non-accruing	202	160
Total Non- Accruing	394	316
Loans and leases	61,778	58,102
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	75	105
Past due, non-accruing	64	19
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	17	33
Past due, non-accruing	128	137
Commercial: | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	33,009	31,567
Total Accruing	33,040	31,628
Current, non-accruing	78	64
Total Non- Accruing	123	153
Loans and leases	33,163	31,781
Commercial: | Commercial, financial and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	28	50
Past due, non-accruing	2	10
Commercial: | Commercial, financial and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	11
Past due, non-accruing	43	79
Commercial: | Commercial, financial and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	30,772	29,309
Total Accruing	30,803	29,370
Current, non-accruing	78	64
Total Non- Accruing	123	153
Loans and leases	30,926	29,523
Nonaccrual, no allowance	108	147
Commercial: | Commercial, financial and industrial | C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	28	50
Past due, non-accruing	2	10
Commercial: | Commercial, financial and industrial | C&I | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	11
Past due, non-accruing	43	79
Commercial: | Commercial, financial and industrial | Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,237	2,258
Total Accruing	2,237	2,258
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	2,237	2,258
Commercial: | Commercial, financial and industrial | Loans to mortgage companies | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	0	0
Commercial: | Commercial, financial and industrial | Loans to mortgage companies | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	0	0
Commercial: | Commercial, financial and industrial | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual, no allowance	117	5
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,121	13,228
Commercial: | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,121	13,228
Commercial: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	187	193
Commercial real estate | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,992	13,208
Total Accruing	13,996	13,219
Current, non-accruing	43	7
Total Non- Accruing	125	9
Loans and leases	14,121	13,228
Commercial real estate | Commercial real estate | CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	11
Past due, non-accruing	50	0
Commercial real estate | Commercial real estate | CRE | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	32	2
Consumer:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,685	12,253
Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,492	12,046
Total Accruing	13,541	12,101
Current, non-accruing	79	88
Total Non- Accruing	144	152
Loans and leases	13,685	12,253
Consumer: | Consumer Real Estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	38	37
Past due, non-accruing	12	9
Consumer: | Consumer Real Estate | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	11	18
Past due, non-accruing	53	55
Consumer: | Consumer Real Estate | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,185	1,967
Total Accruing	2,203	1,984
Current, non-accruing	32	32
Total Non- Accruing	45	44
Loans and leases	2,248	2,028
Nonaccrual, no allowance	5	5
Consumer: | Consumer Real Estate | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	13	12
Past due, non-accruing	4	4
Consumer: | Consumer Real Estate | HELOC | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	5	5
Past due, non-accruing	9	8
Consumer: | Consumer Real Estate | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	11,307	10,079
Total Accruing	11,338	10,117
Current, non-accruing	47	56
Total Non- Accruing	99	108
Loans and leases	11,437	10,225
Nonaccrual, no allowance	10	7
Consumer: | Consumer Real Estate | Real estate installment loans | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	25	25
Past due, non-accruing	8	5
Consumer: | Consumer Real Estate | Real estate installment loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	6	13
Past due, non-accruing	44	47
Consumer: | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	799	827
Total Accruing	807	838
Current, non-accruing	2	1
Total Non- Accruing	2	2
Loans and leases	809	840
Consumer: | Credit Card and Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	5	7
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	4
Past due, non-accruing	0	1
Consumer: | Credit Card and Other | Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	274	287
Total Accruing	281	296
Current, non-accruing	0	0
Total Non- Accruing	0	0
Loans and leases	281	296
Consumer: | Credit Card and Other | Credit card | 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 | Credit card | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	4
Past due, non-accruing	0	0
Consumer: | Credit Card and Other | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	525	540
Total Accruing	526	542
Current, non-accruing	2	1
Total Non- Accruing	2	2
Loans and leases	528	544
Consumer: | Credit Card and Other | Other | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	1	2
Past due, non-accruing	0	0
Consumer: | Credit Card and Other | Other | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	0	0
Past due, non-accruing	$ 0	$ 1