Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions	Mar. 31, 2023		Dec. 31, 2022
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 327,673		$ 325,991
Nonperforming	1,192		1,188
Total loans and leases	327,673		325,991
Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	323,315		320,931
Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,805		2,267
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,361		1,605
Commercial: | Commercial and industrial
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	167,217		164,307
Nonperforming	394		398
Total loans and leases	167,217		164,307
Commercial: | Commercial and industrial | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	166,663		163,604
Commercial: | Commercial and industrial | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	125		256
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	35		49
Commercial: | CRE
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	22,670		22,676
Nonperforming	117		82
Total loans and leases	22,670		22,676
Commercial: | CRE | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	22,519		22,568
Commercial: | CRE | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	34		25
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]
Financing Receivable, before Allowance for Credit Loss	5,951		5,849
Nonperforming	1		0
Total loans and leases	5,951		5,849
Commercial: | Commercial construction | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	5,947		5,844
Commercial: | Commercial construction | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	3		5
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]
Financing Receivable, before Allowance for Credit Loss	56,455		56,645
Nonperforming	233		240
Total loans and leases	56,455		56,645
Consumer: | Residential mortgage | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	55,057		55,005
Consumer: | Residential mortgage | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	491		614
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	674	[1]	786	[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	649		759
Consumer: | Home equity
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,577		10,876
Nonperforming	132		135
Total loans and leases	10,577		10,876
Consumer: | Home equity | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,370		10,661
Consumer: | Home equity | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	65		68
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	10		12
Consumer: | Indirect auto
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	27,279		27,951
Nonperforming	270		289
Total loans and leases	27,279		27,951
Consumer: | Indirect auto | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	26,498		27,015
Consumer: | Indirect auto | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	511		646
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		1
Consumer: | Other consumer
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	27,742		27,533
Nonperforming	45		44
Total loans and leases	27,742		27,533
Consumer: | Other consumer | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	27,523		27,289
Consumer: | Other consumer | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	164		187
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	10		13
Consumer: | Student
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,996		5,287
Nonperforming	0		0
Total loans and leases	4,996		5,287
Consumer: | Student | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,046		4,179
Consumer: | Student | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	356		402
Consumer: | Student | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	594	[1]	706	[2]
Consumer: | Student | 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	590		702
Credit card
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,786		4,867
Nonperforming	0		0
Total loans and leases	4,786		4,867
Credit card | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	4,692		4,766
Credit card | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	56		64
Credit card | Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 38		$ 37

[1] (1)Includes government guaranteed loans of $649 million in the residential mortgage portfolio and $590 million in the student portfolio.

[2] (1)Includes government guaranteed loans of $759 million in the residential mortgage portfolio and $702 million in the student portfolio.