Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 62,445	$ 61,292
Commercial: | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	4,869	4,124
Financing receivable, originated year two	2,990	5,832
Financing receivable, originated year three	4,087	3,664
Financing receivable, originated year four	2,712	1,743
Financing receivable, originated year five	1,199	1,805
Financing receivable, originated prior to year five	4,362	3,605
LMC	3,244	2,024
Revolving Loans	9,271	9,460
Revolving Loans Converted to Term Loans	358	376
Loans and leases	33,092	32,633
Commercial: | Commercial and industrial | PD Grade 1 -12
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	4,726	4,008
Financing receivable, originated year two	2,801	5,637
Financing receivable, originated year three	3,893	3,506
Financing receivable, originated year four	2,523	1,636
Financing receivable, originated year five	1,145	1,665
Financing receivable, originated prior to year five	4,061	3,448
LMC	3,244	2,019
Revolving Loans	8,665	9,087
Revolving Loans Converted to Term Loans	287	327
Loans and leases	31,345	31,333
Commercial: | Commercial and industrial | PD Grade 13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	80	75
Financing receivable, originated year two	44	60
Financing receivable, originated year three	55	64
Financing receivable, originated year four	34	56
Financing receivable, originated year five	17	101
Financing receivable, originated prior to year five	120	57
LMC	0	0
Revolving Loans	332	186
Revolving Loans Converted to Term Loans	33	0
Loans and leases	715	599
Commercial: | Commercial and industrial | PD Grade 14 ,15 and 16
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	63	41
Financing receivable, originated year two	145	135
Financing receivable, originated year three	139	94
Financing receivable, originated year four	155	51
Financing receivable, originated year five	37	39
Financing receivable, originated prior to year five	181	100
LMC	0	5
Revolving Loans	274	187
Revolving Loans Converted to Term Loans	38	49
Loans and leases	1,032	701
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,705	14,216
Commercial: | Commercial real estate | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	486	858
Financing receivable, originated year two	1,209	3,476
Financing receivable, originated year three	3,887	3,652
Financing receivable, originated year four	3,549	1,259
Financing receivable, originated year five	1,159	1,566
Financing receivable, originated prior to year five	3,998	2,994
Revolving Loans	357	393
Revolving Loans Converted to Term Loans	60	18
Loans and leases	14,705	14,216
Commercial: | Commercial real estate | PD Grade 1 -12 | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	486	853
Financing receivable, originated year two	1,154	3,473
Financing receivable, originated year three	3,449	3,518
Financing receivable, originated year four	3,200	1,162
Financing receivable, originated year five	1,010	1,216
Financing receivable, originated prior to year five	3,415	2,853
Revolving Loans	351	393
Revolving Loans Converted to Term Loans	59	18
Loans and leases	13,124	13,486
Commercial: | Commercial real estate | PD Grade 13 | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	5
Financing receivable, originated year two	38	1
Financing receivable, originated year three	239	129
Financing receivable, originated year four	175	86
Financing receivable, originated year five	29	175
Financing receivable, originated prior to year five	121	82
Revolving Loans	0	0
Revolving Loans Converted to Term Loans	1	0
Loans and leases	603	478
Commercial: | Commercial real estate | PD Grade 14 ,15 and 16 | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	0
Financing receivable, originated year two	17	2
Financing receivable, originated year three	199	5
Financing receivable, originated year four	174	11
Financing receivable, originated year five	120	175
Financing receivable, originated prior to year five	462	59
Revolving Loans	6	0
Revolving Loans Converted to Term Loans	0	0
Loans and leases	$ 978	$ 252