Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade (Details) - USD ($) $ in Millions	Jun. 30, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 63,260	$ 62,565
Commercial: | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1,864	5,780
Financing receivable, originated year two	5,681	2,818
Financing receivable, originated year three	2,550	3,840
Financing receivable, originated year four	3,506	2,562
Financing receivable, originated year five	2,192	1,121
Financing receivable, originated prior to year five	4,767	4,079
LMC	4,058	3,471
Revolving Loans	9,514	9,446
Revolving Loans Converted to Term Loans	227	311
Loans and leases	34,359	33,428
Commercial: | Commercial and industrial | Pass (PD grades 1 through 12)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1,850	5,590
Financing receivable, originated year two	5,466	2,607
Financing receivable, originated year three	2,337	3,649
Financing receivable, originated year four	3,171	2,336
Financing receivable, originated year five	1,993	1,055
Financing receivable, originated prior to year five	4,444	3,853
LMC	4,056	3,471
Revolving Loans	8,972	8,784
Revolving Loans Converted to Term Loans	185	248
Loans and leases	32,474	31,593
Commercial: | Commercial and industrial | Special Mention (PD grade 13)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	1	106
Financing receivable, originated year two	112	27
Financing receivable, originated year three	59	78
Financing receivable, originated year four	85	47
Financing receivable, originated year five	38	33
Financing receivable, originated prior to year five	86	57
LMC	2	0
Revolving Loans	193	279
Revolving Loans Converted to Term Loans	14	2
Loans and leases	590	629
Commercial: | Commercial and industrial | Substandard, Doubtful, or Loss (PD grades 14,15, and 16)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	13	84
Financing receivable, originated year two	103	184
Financing receivable, originated year three	154	113
Financing receivable, originated year four	250	179
Financing receivable, originated year five	161	33
Financing receivable, originated prior to year five	237	169
LMC	0	0
Revolving Loans	349	383
Revolving Loans Converted to Term Loans	28	61
Loans and leases	1,295	1,206
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,936	14,421
Commercial: | Commercial real estate | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	351	697
Financing receivable, originated year two	860	1,369
Financing receivable, originated year three	1,626	3,813
Financing receivable, originated year four	3,411	3,254
Financing receivable, originated year five	2,732	1,047
Financing receivable, originated prior to year five	4,473	3,847
Revolving Loans	393	346
Revolving Loans Converted to Term Loans	90	48
Loans and leases	13,936	14,421
Commercial: | Commercial real estate | Pass (PD grades 1 through 12) | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	348	694
Financing receivable, originated year two	856	1,296
Financing receivable, originated year three	1,570	3,282
Financing receivable, originated year four	2,832	2,778
Financing receivable, originated year five	2,274	894
Financing receivable, originated prior to year five	3,864	3,281
Revolving Loans	344	340
Revolving Loans Converted to Term Loans	90	47
Loans and leases	12,178	12,612
Commercial: | Commercial real estate | Special Mention (PD grade 13) | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	0
Financing receivable, originated year two	0	42
Financing receivable, originated year three	8	280
Financing receivable, originated year four	198	198
Financing receivable, originated year five	286	37
Financing receivable, originated prior to year five	129	130
Revolving Loans	43	0
Revolving Loans Converted to Term Loans	0	1
Loans and leases	664	688
Commercial: | Commercial real estate | Substandard, Doubtful, or Loss (PD grades 14,15, and 16) | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	3	3
Financing receivable, originated year two	4	31
Financing receivable, originated year three	48	251
Financing receivable, originated year four	381	278
Financing receivable, originated year five	172	116
Financing receivable, originated prior to year five	480	436
Revolving Loans	6	6
Revolving Loans Converted to Term Loans	0	0
Loans and leases	$ 1,094	$ 1,121