Loans - Summary of TDRs (Detail) $ in Millions	Dec. 31, 2022 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	$ 538
Residential mortgage loan TDR carried at lower of amortized cost or fair value less cost to sell	99
Non Accrual loans included in TDR loan	122
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	388
Additional commitments to lend to commercial borrowers with modified TDRs	38
Commercial loans \| Business and corporate banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	382
Commercial loans \| Global banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	6
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	150
Consumer loans \| Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	136
Consumer loans \| Home equity mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	12
Consumer loans \| Credit cards
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDR Loans	$ 2

Residential Mortgage Loan TDR Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell

No definition available.

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- Definition

Trouble debt restructuring non accrual loan.

+ References

No definition available.

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- Definition

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+ References

No definition available.

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- Definition

Accumulated amortized cost of financing receivable modified for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-42

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
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-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-33

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 310
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-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481746/310-40-50-4

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- Definition

Amount of commitment to lend additional funds to debtor experiencing financial difficulty for which creditor has modified terms of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 36
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-36

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 1
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-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481746/310-40-50-1

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