Loans - Loans Classified as TDR Loans (Detail) - Consumer loans - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Modified [Line Items]
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent	$ 0	$ 5
Residential mortgages
Financing Receivable, Modified [Line Items]
Loans which were classified as TDR loans during previous 12 months which became contractually delinquent	$ 0	$ 5

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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