Loans and Leases - Balances Of Commercial Loan Portfolio Classes, Disaggregated By PD Grade (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 61,753	$ 61,292
Commercial and industrial | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	706	4,124
Financing receivable, originated year two	4,056	5,832
Financing receivable, originated year three	5,555	3,664
Financing receivable, originated year four	3,508	1,743
Financing receivable, originated year five	1,654	1,805
Financing receivable, originated prior to year five	5,224	3,605
LMC	2,366	2,024
Revolving Loans	9,494	9,460
Revolving Loans Converted to Term Loans	348	376
Loans and leases	32,911	32,633
Commercial and industrial | PD Grade 1 -12 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	703	4,008
Financing receivable, originated year two	3,885	5,637
Financing receivable, originated year three	5,346	3,506
Financing receivable, originated year four	3,328	1,636
Financing receivable, originated year five	1,537	1,665
Financing receivable, originated prior to year five	4,874	3,448
LMC	2,362	2,019
Revolving Loans	8,999	9,087
Revolving Loans Converted to Term Loans	309	327
Loans and leases	31,343	31,333
Commercial and industrial | PD Grade 13 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1	75
Financing receivable, originated year two	127	60
Financing receivable, originated year three	73	64
Financing receivable, originated year four	87	56
Financing receivable, originated year five	69	101
Financing receivable, originated prior to year five	167	57
LMC	0	0
Revolving Loans	332	186
Revolving Loans Converted to Term Loans	2	0
Loans and leases	858	599
Commercial and industrial | PD Grade 14 ,15 and 16 | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	2	41
Financing receivable, originated year two	44	135
Financing receivable, originated year three	136	94
Financing receivable, originated year four	93	51
Financing receivable, originated year five	48	39
Financing receivable, originated prior to year five	183	100
LMC	4	5
Revolving Loans	163	187
Revolving Loans Converted to Term Loans	37	49
Loans and leases	710	701
Commercial real estate | Commercial:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,426	14,216
Commercial real estate | Commercial: | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	104	858
Financing receivable, originated year two	958	3,476
Financing receivable, originated year three	3,693	3,652
Financing receivable, originated year four	3,705	1,259
Financing receivable, originated year five	1,243	1,566
Financing receivable, originated prior to year five	4,364	2,994
Revolving Loans	344	393
Revolving Loans Converted to Term Loans	15	18
Loans and leases	14,426	14,216
Commercial real estate | PD Grade 1 -12 | Commercial: | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	104	853
Financing receivable, originated year two	955	3,473
Financing receivable, originated year three	3,611	3,518
Financing receivable, originated year four	3,513	1,162
Financing receivable, originated year five	1,107	1,216
Financing receivable, originated prior to year five	3,869	2,853
Revolving Loans	337	393
Revolving Loans Converted to Term Loans	15	18
Loans and leases	13,511	13,486
Commercial real estate | PD Grade 13 | Commercial: | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	5
Financing receivable, originated year two	1	1
Financing receivable, originated year three	76	129
Financing receivable, originated year four	182	86
Financing receivable, originated year five	86	175
Financing receivable, originated prior to year five	239	82
Revolving Loans	4	0
Revolving Loans Converted to Term Loans	0	0
Loans and leases	588	478
Commercial real estate | PD Grade 14 ,15 and 16 | Commercial: | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	0
Financing receivable, originated year two	2	2
Financing receivable, originated year three	6	5
Financing receivable, originated year four	10	11
Financing receivable, originated year five	50	175
Financing receivable, originated prior to year five	256	59
Revolving Loans	3	0
Revolving Loans Converted to Term Loans	0	0
Loans and leases	$ 327	$ 252