Loans and Leases - Balances of Commercial Loan Portfolio Classes, Disaggregated by PD Grade (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 62,215	$ 62,565
Commercial: | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	757	5,780
Financing receivable, originated year two	5,985	2,818
Financing receivable, originated year three	2,710	3,840
Financing receivable, originated year four	3,656	2,562
Financing receivable, originated year five	2,343	1,121
Financing receivable, originated prior to year five	4,984	4,079
LMC	3,369	3,471
Revolving Loans	9,299	9,446
Revolving Loans Converted to Term Loans	251	311
Loans and leases	33,354	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	756	5,590
Financing receivable, originated year two	5,804	2,607
Financing receivable, originated year three	2,525	3,649
Financing receivable, originated year four	3,344	2,336
Financing receivable, originated year five	2,127	1,055
Financing receivable, originated prior to year five	4,674	3,853
LMC	3,369	3,471
Revolving Loans	8,744	8,784
Revolving Loans Converted to Term Loans	211	248
Loans and leases	31,554	31,593
Commercial: | Commercial and industrial | Special Mention (PD grade 13)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	0	106
Financing receivable, originated year two	72	27
Financing receivable, originated year three	25	78
Financing receivable, originated year four	82	47
Financing receivable, originated year five	55	33
Financing receivable, originated prior to year five	69	57
LMC	0	0
Revolving Loans	193	279
Revolving Loans Converted to Term Loans	6	2
Loans and leases	502	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	1	84
Financing receivable, originated year two	109	184
Financing receivable, originated year three	160	113
Financing receivable, originated year four	230	179
Financing receivable, originated year five	161	33
Financing receivable, originated prior to year five	241	169
LMC	0	0
Revolving Loans	362	383
Revolving Loans Converted to Term Loans	34	61
Loans and leases	1,298	1,206
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	14,139	14,421
Commercial: | Commercial real estate | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, originated year one	160	697
Financing receivable, originated year two	756	1,369
Financing receivable, originated year three	1,466	3,813
Financing receivable, originated year four	3,684	3,254
Financing receivable, originated year five	3,031	1,047
Financing receivable, originated prior to year five	4,632	3,847
Revolving Loans	353	346
Revolving Loans Converted to Term Loans	57	48
Loans and leases	14,139	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	160	694
Financing receivable, originated year two	753	1,296
Financing receivable, originated year three	1,391	3,282
Financing receivable, originated year four	3,179	2,778
Financing receivable, originated year five	2,457	894
Financing receivable, originated prior to year five	3,990	3,281
Revolving Loans	304	340
Revolving Loans Converted to Term Loans	57	47
Loans and leases	12,291	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	42	280
Financing receivable, originated year four	172	198
Financing receivable, originated year five	267	37
Financing receivable, originated prior to year five	121	130
Revolving Loans	43	0
Revolving Loans Converted to Term Loans	0	1
Loans and leases	645	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	0	3
Financing receivable, originated year two	3	31
Financing receivable, originated year three	33	251
Financing receivable, originated year four	333	278
Financing receivable, originated year five	307	116
Financing receivable, originated prior to year five	521	436
Revolving Loans	6	6
Revolving Loans Converted to Term Loans	0	0
Loans and leases	$ 1,203	$ 1,121