Loans - Loan Payment Modifications by Type of Modification (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Modified [Line Items]
Loans modified	$ 292	$ 357
% of Total Loans	0.50%	0.60%
Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified	$ 284	$ 349
% of Total Loans	0.70%	0.90%
Commercial loans \| Real estate, including construction
Financing Receivable, Modified [Line Items]
Loans modified	$ 235	$ 235
% of Total Loans	3.30%	3.30%
Commercial loans \| Business and corporate banking
Financing Receivable, Modified [Line Items]
Loans modified	$ 44	$ 109
% of Total Loans	0.30%	0.70%
Commercial loans \| Global banking
Financing Receivable, Modified [Line Items]
Loans modified	$ 5	$ 5
% of Total Loans	0.00%	0.00%
Consumer loans
Financing Receivable, Modified [Line Items]
Loans modified	$ 8	$ 8
% of Total Loans	0.00%	0.00%
Consumer loans \| Residential mortgages
Financing Receivable, Modified [Line Items]
Loans modified	$ 8	$ 8
% of Total Loans	0.00%	0.00%
Consumer mortgage loans with payment modifications carried at the lower of amortized cost or fair value	$ 8	$ 8
Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Commercial loans \| Real estate, including construction
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Commercial loans \| Business and corporate banking
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Commercial loans \| Global banking
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Consumer loans
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Interest Rate Reduction \| Consumer loans \| Residential mortgages
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Commercial loans \| Real estate, including construction
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Commercial loans \| Business and corporate banking
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Commercial loans \| Global banking
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Consumer loans
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Principal Forgiveness \| Consumer loans \| Residential mortgages
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Term Extension / Significant Payment Deferral
Financing Receivable, Modified [Line Items]
Loans modified	291	344
Term Extension / Significant Payment Deferral \| Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified	284	337
Term Extension / Significant Payment Deferral \| Commercial loans \| Real estate, including construction
Financing Receivable, Modified [Line Items]
Loans modified	235	235
Term Extension / Significant Payment Deferral \| Commercial loans \| Business and corporate banking
Financing Receivable, Modified [Line Items]
Loans modified	44	97
Term Extension / Significant Payment Deferral \| Commercial loans \| Global banking
Financing Receivable, Modified [Line Items]
Loans modified	5	5
Term Extension / Significant Payment Deferral \| Consumer loans
Financing Receivable, Modified [Line Items]
Loans modified	7	7
Term Extension / Significant Payment Deferral \| Consumer loans \| Residential mortgages
Financing Receivable, Modified [Line Items]
Loans modified	7	7
Combination
Financing Receivable, Modified [Line Items]
Loans modified	1	13
Combination \| Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified	0	12
Combination \| Commercial loans \| Real estate, including construction
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Combination \| Commercial loans \| Business and corporate banking
Financing Receivable, Modified [Line Items]
Loans modified	0	12
Combination \| Commercial loans \| Global banking
Financing Receivable, Modified [Line Items]
Loans modified	0	0
Combination \| Consumer loans
Financing Receivable, Modified [Line Items]
Loans modified	1	1
Combination \| Consumer loans \| Residential mortgages
Financing Receivable, Modified [Line Items]
Loans modified	$ 1	$ 1

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- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

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- Definition

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+ References

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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