Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions	Jun. 30, 2025		Dec. 31, 2024
Financing Receivable [Line Items]
Nonperforming	$ 1,251		$ 1,429
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	318,796		306,383
Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	315,188		302,418
Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,811		1,949
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	546		587
Commercial: | Commercial and industrial
Financing Receivable [Line Items]
Nonperforming	520		521
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	162,273		154,848
Commercial: | Commercial and industrial | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	161,629		154,140
Commercial: | Commercial and industrial | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	122		168
Commercial: | Commercial and industrial | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	2		19
Commercial: | CRE
Financing Receivable [Line Items]
Nonperforming	128		298
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	20,270		20,363
Commercial: | CRE | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	20,108		20,004
Commercial: | CRE | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	34		60
Commercial: | CRE | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	0		1
Commercial: | Commercial construction
Financing Receivable [Line Items]
Nonperforming	1		3
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	8,277		8,520
Commercial: | Commercial construction | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,261		8,514
Commercial: | Commercial construction | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	15		3
Commercial: | Commercial construction | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	0		0
Consumer: | Residential mortgage
Financing Receivable [Line Items]
Nonperforming	191		166
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	57,828		55,599
Consumer: | Residential mortgage | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	56,477		54,233
Consumer: | Residential mortgage | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	695		719
Consumer: | Residential mortgage | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	465	[1]	481	[2]
Consumer: | Residential mortgage | Financial Asset, Equal to or Greater than 90 Days Past Due | Loans Insured or Guaranteed by US Government Authorities
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	424		430
Consumer: | Home equity
Financing Receivable [Line Items]
Nonperforming	107		116
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	9,591		9,642
Consumer: | Home equity | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,424		9,457
Consumer: | Home equity | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	54		60
Consumer: | Home equity | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	6		9
Consumer: | Indirect auto
Financing Receivable [Line Items]
Nonperforming	240		259
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	24,558		23,089
Consumer: | Indirect auto | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	23,736		22,208
Consumer: | Indirect auto | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	582		622
Consumer: | Indirect auto | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	0		0
Consumer: | Other consumer
Financing Receivable [Line Items]
Nonperforming	64		66
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	31,122		29,395
Consumer: | Other consumer | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	30,795		29,070
Consumer: | Other consumer | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	239		236
Consumer: | Other consumer | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	24		23
Credit card
Financing Receivable [Line Items]
Nonperforming	0		0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	4,877		4,927
Credit card | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,758		4,792
Credit card | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	70		81
Credit card | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 49		$ 54

[1] (1)Includes government guaranteed loans of $424 million in the residential mortgage portfolio.

[2] (1)Includes government guaranteed loans of $430 million in the residential mortgage portfolio.