Loans - Narrative (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net deferred origination costs (fees)		$ 27		$ 27		$ 40
Net unamortized premium (discount)		(9)		(9)		5
Interest income that was recorded on nonaccrual loans and included in interest income during the period		3	$ 6	8	$ 31
Loans	[1]	61,775		61,775		55,864
Interest only residential mortgage loans		4,029		4,029		3,739
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 17,308		$ 17,308		16,068
Weighted average rate of reduction		1.25%	3.13%	0.25%	2.08%
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		$ 0	$ 1	$ 0	$ 4
Threshold period for troubled debt restructuring status		60 days	60 days	60 days	60 days
Consumer loans | Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		$ 248		$ 248		214
Loans		16,691		16,691		15,469
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		0	$ 1	0	$ 4
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Collateral-dependent loans		241		241		347
Loans		44,467		44,467		$ 39,796
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent		$ 0	$ 0	$ 0	$ 0
Threshold period for troubled debt restructuring status		90 days	90 days	90 days	90 days

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at September 30, 2022 and December 31, 2021. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 17, "Variable Interest Entities," for additional information. September 30, 2022December 31, 2021(in millions)AssetsLoans$127 $46 Other assets44 55 Total assets$171 $101 LiabilitiesInterest, taxes and other liabilities$26 $9 Total liabilities$26 $9