Accounting and Reporting Developments (Details) - USD ($) $ in Millions		9 Months Ended
	Jun. 30, 2023	Sep. 30, 2023		Jan. 01, 2023	Dec. 31, 2022		Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (2,327)	$ (2,340)	[1]		$ (2,194)	[1]	$ (2,099)	$ (2,014)	$ (1,892)
Retained earnings		$ 22,747			21,689
Loans modified maintained on nonaccrual status, payment history, period		6 months
SOFR
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Basis spread on variable rate (as a percent)	0.26161%
Chapter 7 Bankruptcy
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans modified maintained on accrual status, payment history, period		12 months
Large Commercial Loans And Leases
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Established threshold nonaccrual commercial loans		$ 1
Commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (1,199)	$ (1,187)			(1,127)		(1,158)	(1,165)	(1,102)
Threshold period past due for nonaccrual loans		90 days
Loans modified maintained on accrual status, payment history, period		6 months
Carrying value of loans and leases evaluated for ALLL		$ 1
Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	(173)	$ (155)			(245)		(254)	(248)	(235)
Residential Mortgage | Residential mortgage loans
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Threshold period past due for nonaccrual loans		150 days
Foreclosure process, period		180 days
Threshold period past due for accrual loans		90 days
Consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (955)	$ (998)			(822)		$ (687)	$ (601)	$ (555)
Consumer | Home equity
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Threshold period past due for nonaccrual loans		90 days
Threshold period past due for nonaccrual loans, with senior lien in default		60 days
Senior lien in default, threshold period		120 days
Consumer | Credit card
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Threshold period past due		90 days
Loans modified maintained on nonaccrual status, payment history, period		6 months
Loans modified maintained on accrual status, payment history, period		6 months
Consumer | Indirect Secured Consumer Loan And Other Consumer Loan
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Threshold period past due for nonaccrual loans		90 days
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses					49
Cumulative Effect, Period of Adoption, Adjustment | Commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses					(4)
Cumulative Effect, Period of Adoption, Adjustment | Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses					36
Cumulative Effect, Period of Adoption, Adjustment | Consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses					$ 17
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2022-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses				$ 49
Retained earnings				$ 37

[1] Includes $59 and $17 of other short-term investments, $1,728 and $185 of portfolio loans and leases, $(27) and $(2) of ALLL, $11 and $2 of other assets, $15 and $9 of other liabilities, and $1,553 and $118 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2023 and December 31, 2022, respectively. For further information, refer to Note 12.