Loans - Additional Information (Detail) - USD ($)		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred origination costs (fees)		$ 40,000,000	$ 57,000,000
Net unamortized premium (discount)		5,000,000	9,000,000
Interest income that was recorded on nonaccrual loans and included in interest income during the period		34,000,000	12,000,000	$ 15,000,000
Commercial loans removed from TDR classification		0	0	$ 12,000,000
Loans	[1]	55,864,000,000	62,088,000,000
Interest only residential mortgage loans		$ 3,739,000,000	$ 3,597,000,000
Affiliated Entity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Executive loans as percent of total equity, maximum (in percent)		5.00%	5.00%
Payment Deferral | COVID-19
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 76,000,000
Consumer loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 16,068,000,000	$ 20,489,000,000
Weighted average rate of reduction		2.08%	1.75%	2.18%
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		$ 5,000,000	$ 5,000,000	$ 3,000,000
Threshold period for troubled debt restructuring status		60 days	60 days	60 days
Consumer loans: | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		$ 214,000,000	$ 817,000,000
Loans		15,469,000,000	18,377,000,000
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		5,000,000	5,000,000	$ 3,000,000
Commercial loans:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		347,000,000	456,000,000
Loans		39,796,000,000	41,599,000,000
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		$ 0	$ 0	$ 0
Threshold period for troubled debt restructuring status		90 days	90 days	90 days

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2021 and 2020. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 27, "Variable Interest Entities," for additional information. At December 31,20212020(in millions)AssetsLoans$46 $10 Other assets55 79 Total assets$101 $89 LiabilitiesInterest, taxes and other liabilities$9 $10 Total liabilities$9 $10