Loans and Leases - Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 61,778	$ 58,102
Commercial and industrial | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	3,352	7,509
Financing receivable, originated year two	6,099	3,738
Financing receivable, originated year three	3,912	1,861
Financing receivable, originated year four	1,812	2,071
Financing receivable, originated year five	1,911	1,145
Financing receivable, originated prior to year five	3,790	3,305
LMC	2,237	2,258
Revolving Loans	9,588	9,426
Revolving Loans Converted to Term Loans	462	468
Loans and leases	33,163	31,781
Commercial and industrial | PD Grade 1 -12 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	3,351	7,456
Financing receivable, originated year two	5,945	3,634
Financing receivable, originated year three	3,796	1,803
Financing receivable, originated year four	1,710	1,912
Financing receivable, originated year five	1,772	1,112
Financing receivable, originated prior to year five	3,634	3,170
LMC	2,237	2,258
Revolving Loans	9,302	9,166
Revolving Loans Converted to Term Loans	358	371
Loans and leases	32,105	30,882
Commercial and industrial | PD Grade 13 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1	17
Financing receivable, originated year two	31	56
Financing receivable, originated year three	54	17
Financing receivable, originated year four	53	125
Financing receivable, originated year five	100	8
Financing receivable, originated prior to year five	60	80
LMC	0	0
Revolving Loans	139	126
Revolving Loans Converted to Term Loans	1	0
Loans and leases	439	429
Commercial and industrial | PD Grade 14 ,15 and 16 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	36
Financing receivable, originated year two	123	48
Financing receivable, originated year three	62	41
Financing receivable, originated year four	49	34
Financing receivable, originated year five	39	25
Financing receivable, originated prior to year five	96	55
LMC	0	0
Revolving Loans	147	134
Revolving Loans Converted to Term Loans	103	97
Loans and leases	619	470
Commercial real estate | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,121	13,228
Commercial real estate | Commercial: | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	664	2,638
Financing receivable, originated year two	3,358	3,331
Financing receivable, originated year three	3,651	1,503
Financing receivable, originated year four	1,347	1,942
Financing receivable, originated year five	1,619	907
Financing receivable, originated prior to year five	3,139	2,601
Revolving Loans	324	286
Revolving Loans Converted to Term Loans	19	20
Loans and leases	14,121	13,228
Commercial real estate | PD Grade 1 -12 | Commercial: | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	663	2,637
Financing receivable, originated year two	3,355	3,324
Financing receivable, originated year three	3,643	1,488
Financing receivable, originated year four	1,306	1,855
Financing receivable, originated year five	1,331	808
Financing receivable, originated prior to year five	2,978	2,565
Revolving Loans	316	274
Revolving Loans Converted to Term Loans	19	20
Loans and leases	13,611	12,971
Commercial real estate | PD Grade 13 | Commercial: | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1	0
Financing receivable, originated year two	1	3
Financing receivable, originated year three	3	3
Financing receivable, originated year four	30	37
Financing receivable, originated year five	147	68
Financing receivable, originated prior to year five	77	5
Revolving Loans	0	1
Revolving Loans Converted to Term Loans	0	0
Loans and leases	259	117
Commercial real estate | PD Grade 14 ,15 and 16 | Commercial: | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	1
Financing receivable, originated year two	2	4
Financing receivable, originated year three	5	12
Financing receivable, originated year four	11	50
Financing receivable, originated year five	141	31
Financing receivable, originated prior to year five	84	31
Revolving Loans	8	11
Revolving Loans Converted to Term Loans	0	0
Loans and leases	$ 251	$ 140