Loans and ACL - Aging Analysis of Loans and Leases (Details) - USD ($) $ in Millions		Jun. 30, 2023		Dec. 31, 2022
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		$ 322,092		$ 325,991
Nonperforming		1,511		1,188
Total loans and leases		322,092		325,991
Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		318,369		320,931
Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		1,550		2,267
Financial Asset, Equal to or Greater than 90 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		662		1,605
Commercial: | Commercial and industrial
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		167,153		164,307
Nonperforming		562		398
Total loans and leases		167,153		164,307
Commercial: | Commercial and industrial | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		166,413		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		142		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		36		49
Commercial: | CRE
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		22,825		22,676
Nonperforming		275		82
Total loans and leases		22,825		22,676
Commercial: | CRE | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		22,512		22,568
Commercial: | CRE | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		38		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		5,943		5,849
Nonperforming		16		0
Total loans and leases		5,943		5,849
Commercial: | Commercial construction | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		5,916		5,844
Commercial: | Commercial construction | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		6		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		5		0
Consumer: | Residential mortgage
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		56,476		56,645
Nonperforming		221		240
Total loans and leases		56,476		56,645
Consumer: | Residential mortgage | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		55,170		55,005
Consumer: | Residential mortgage | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		521		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		564	[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		541		759
Consumer: | Home equity
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		10,348		10,876
Nonperforming		129		135
Total loans and leases		10,348		10,876
Consumer: | Home equity | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		10,156		10,661
Consumer: | Home equity | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		56		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		7		12
Consumer: | Indirect auto
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		25,759		27,951
Nonperforming		262		289
Total loans and leases		25,759		27,951
Consumer: | Indirect auto | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		24,948		27,015
Consumer: | Indirect auto | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		549		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		28,755		27,533
Nonperforming		46		44
Total loans and leases		28,755		27,533
Consumer: | Other consumer | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		28,522		27,289
Consumer: | Other consumer | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		175		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		12		13
Consumer: | Student
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss				5,287
Nonperforming				0
Total loans and leases				5,287
Consumer: | Student | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss				4,179
Consumer: | Student | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss				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	[2]			706
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				702
Credit card
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		4,833		4,867
Nonperforming		0		0
Total loans and leases		4,833		4,867
Credit card | Financial Asset, Not Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		4,732		4,766
Credit card | Financing Receivables 30 To 89 Days Past Due
Financing Receivable [Line Items]
Financing Receivable, before Allowance for Credit Loss		63		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 $541 million in the residential mortgage portfolio.

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