Accounting and Reporting Developments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023		Jan. 01, 2023	Dec. 31, 2022		Mar. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (2,215)	[1]		$ (2,194)	[1]	$ (1,908)	$ (1,892)
Retained earnings	$ 22,032			21,689
Loans modified maintained on nonaccrual status, payment history, period	6 months
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]
Carrying value of loans and leases evaluated for ALLL	$ 1
Commercial
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (1,143)			(1,127)		(1,110)	(1,102)
Threshold period past due for nonaccrual loans	90 days
Loans modified maintained on accrual status, payment history, period	6 months
Established threshold nonaccrual commercial loans	$ 1
Residential Mortgage
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for loan and lease losses	$ (185)			(245)		(239)	(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	$ (887)			(822)		$ (559)	$ (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 $5 and $17 of other short-term investments, $44 and $185 of portfolio loans and leases, $(1) and $(2) of ALLL, $0 and $2 of other assets, $9 and $9 of other liabilities, and $38 and $118 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2023 and December 31, 2022, respectively. For further information, refer to Note 12.