Loans and Leases - Accruing And Non-Accruing Loans By Class (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	$ 60,724	$ 57,648
Total accruing	60,830	57,786
Current, non-accruing	228	160
Total non-accruing	462	316
Loans and leases	61,292	58,102
30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	85	105
Past due, non-accruing	30	19
90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	21	33
Past due, non-accruing	204	137
Commercial | Commercial, financial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	32,416	31,567
Total accruing	32,449	31,628
Current, non-accruing	113	64
Total non-accruing	184	153
Loans and leases	32,633	31,781
Commercial | Commercial, financial and industrial | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	32	50
Past due, non-accruing	18	10
Commercial | Commercial, financial and industrial | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	1	11
Past due, non-accruing	53	79
Commercial | Commercial, financial and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	30,403	29,309
Total accruing	30,435	29,370
Current, non-accruing	108	64
Total non-accruing	179	153
Loans and leases	30,614	29,523
Nonaccrual, no allowance	178	147
Commercial | Commercial, financial and industrial | C&I | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	31	50
Past due, non-accruing	18	10
Commercial | Commercial, financial and industrial | C&I | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	1	11
Past due, non-accruing	53	79
Commercial | Commercial, financial and industrial | Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,013	2,258
Total accruing	2,014	2,258
Current, non-accruing	5	0
Total non-accruing	5	0
Loans and leases	2,019	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	1	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	129	5
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,216	13,228
Commercial | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	14,072	13,208
Total accruing	14,080	13,219
Current, non-accruing	41	7
Total non-accruing	136	9
Loans and leases	14,216	13,228
Commercial | Commercial real estate | CRE | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	8	11
Past due, non-accruing	0	0
Commercial | 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	95	2
Commercial | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	180	193
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,650	12,253
Consumer | Consumer real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	13,453	12,046
Total accruing	13,510	12,101
Current, non-accruing	73	88
Total non-accruing	140	152
Loans and leases	13,650	12,253
Consumer | Consumer real estate | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	40	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	17	18
Past due, non-accruing	55	55
Consumer | Consumer real estate | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	2,158	1,967
Total accruing	2,173	1,984
Current, non-accruing	30	32
Total non-accruing	46	44
Loans and leases	2,219	2,028
Nonaccrual, no allowance	4	5
Consumer | Consumer real estate | HELOC | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	11	12
Past due, non-accruing	6	4
Consumer | Consumer real estate | HELOC | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	4	5
Past due, non-accruing	10	8
Consumer | Consumer real estate | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	11,295	10,079
Total accruing	11,337	10,117
Current, non-accruing	43	56
Total non-accruing	94	108
Loans and leases	11,431	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	29	25
Past due, non-accruing	6	5
Consumer | Consumer real estate | Real estate installment loans | 90+ Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	13	13
Past due, non-accruing	45	47
Consumer | Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	783	827
Total accruing	791	838
Current, non-accruing	1	1
Total non-accruing	2	2
Loans and leases	793	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	1	1
Consumer | Credit Card and Other | Credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current, accruing	271	287
Total accruing	277	296
Current, non-accruing	0	0
Total non-accruing	0	0
Loans and leases	277	296
Consumer | Credit Card and Other | Credit card | 30-89 Days Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Past due, accruing	3	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	512	540
Total accruing	514	542
Current, non-accruing	1	1
Total non-accruing	2	2
Loans and leases	516	544
Consumer | Credit Card and Other | 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
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	$ 1	$ 1