Commitments and contingent liabilities - Standby Letters of Credits by Investment Grade (Details) - Standby letters of credit	Sep. 30, 2021	Dec. 31, 2020
Investment grade
Concentration Risk [Line Items]
Standby letters of credit by investment grade	85.00%	82.00%
Non-investment grade
Concentration Risk [Line Items]
Standby letters of credit by investment grade	15.00%	18.00%

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.

No definition available.

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