Fair Value Measurements - Carrying Value and Estimated Fair Value of Financial Instruments (Detail) - USD ($) $ in Millions		Jun. 30, 2023		Dec. 31, 2022		Jun. 30, 2022
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Federal funds sold and securities purchased under agreements to resell	[1]	$ 12,519		$ 23,085
Total loans, net		57,340	[1]	58,796	[1]	$ 61,264
Loans held for sale	[1]	997		354
Deposits		121,636	[1]	123,223	[1]	$ 127,263
Long-term debt	[1]	19,671		17,591
Level 1
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Short-term financial assets, net of allowance for credit losses		831		1,004
Federal funds sold and securities purchased under agreements to resell		0		0
Securities held-to-maturity, net of allowance for credit losses		0		0
Short-term financial liabilities		0		0
Deposits		0		0
Long-term debt		0		0
Level 1 | Commercial loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		0		0
Loans held for sale		0		0
Level 1 | Consumer loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		0		0
Loans held for sale		0		0
Level 2
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Short-term financial assets, net of allowance for credit losses		29,476		17,744
Federal funds sold and securities purchased under agreements to resell		12,519		23,085
Securities held-to-maturity, net of allowance for credit losses		12,872		6,862
Short-term financial liabilities		8,227		5,945
Deposits		120,233		121,652
Long-term debt		11,024		9,769
Level 2 | Commercial loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		0		0
Loans held for sale		622		112
Level 2 | Consumer loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		0		0
Loans held for sale		1		5
Level 3
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Short-term financial assets, net of allowance for credit losses		32		54
Federal funds sold and securities purchased under agreements to resell		0		0
Securities held-to-maturity, net of allowance for credit losses		0		0
Short-term financial liabilities		32		54
Deposits		0		0
Long-term debt		0		0
Level 3 | Commercial loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		39,568		42,050
Loans held for sale		0		0
Level 3 | Consumer loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		16,042		15,984
Loans held for sale		0		0
Carrying Value
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Short-term financial assets, net of allowance for credit losses		30,339		18,802
Federal funds sold and securities purchased under agreements to resell		12,519		23,085
Securities held-to-maturity, net of allowance for credit losses		13,428		7,317
Short-term financial liabilities		8,259		5,999
Deposits		120,284		121,669
Long-term debt		10,465		9,213
Carrying Value | Commercial loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		39,218		41,266
Loans held for sale		622		112
Carrying Value | Consumer loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		18,105		17,510
Loans held for sale		1		5
Fair Value
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Short-term financial assets, net of allowance for credit losses		30,339		18,802
Federal funds sold and securities purchased under agreements to resell		12,519		23,085
Securities held-to-maturity, net of allowance for credit losses		12,872		6,862
Short-term financial liabilities		8,259		5,999
Deposits		120,233		121,652
Long-term debt		11,024		9,769
Fair Value | Commercial loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		39,568		42,050
Loans held for sale		622		112
Fair Value | Consumer loans
Fair Value Disclosure, Asset and Liability, Not Measured at Fair Value [Line Items]
Total loans, net		16,042		15,984
Loans held for sale		$ 1		$ 5

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at June 30, 2023 and December 31, 2022. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. June 30, 2023December 31, 2022(in millions)AssetsLoans, net$186 $162 Other assets40 44 Total assets$226 $206 LiabilitiesInterest, taxes and other liabilities$35 $22 Total liabilities$35 $22