Allowance for credit losses - Troubled debt restructurings loan count by type of modification (Details) - loans	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Modifications [Line Items]
Loan count	1,706	2,373
Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	174	372
Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	352	313
Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	890	1,604
Other
Financing Receivable, Modifications [Line Items]
Loan count	290	84
Mortgages
Financing Receivable, Modifications [Line Items]
Loan count	1,110	1,774
Mortgages | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	7	39
Mortgages | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	217	140
Mortgages | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	881	1,590
Mortgages | Other
Financing Receivable, Modifications [Line Items]
Loan count	5	5
Commercial | Commercial multi-family
Financing Receivable, Modifications [Line Items]
Loan count		2
Commercial | Commercial multi-family | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count		0
Commercial | Commercial multi-family | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count		1
Commercial | Commercial multi-family | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count		1
Commercial | Commercial multi-family | Other
Financing Receivable, Modifications [Line Items]
Loan count		0
Commercial | CRE non-owner occupied
Financing Receivable, Modifications [Line Items]
Loan count	8	12
Commercial | CRE non-owner occupied | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Commercial | CRE non-owner occupied | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	2	11
Commercial | CRE non-owner occupied | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	2	1
Commercial | CRE non-owner occupied | Other
Financing Receivable, Modifications [Line Items]
Loan count	4	0
Commercial | CRE owner occupied
Financing Receivable, Modifications [Line Items]
Loan count	28	43
Commercial | CRE owner occupied | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	3	4
Commercial | CRE owner occupied | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	10	23
Commercial | CRE owner occupied | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	1	4
Commercial | CRE owner occupied | Other
Financing Receivable, Modifications [Line Items]
Loan count	14	12
Commercial | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Loan count	30	39
Commercial | Commercial and Industrial | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	4	5
Commercial | Commercial and Industrial | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	9	13
Commercial | Commercial and Industrial | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	1	0
Commercial | Commercial and Industrial | Other
Financing Receivable, Modifications [Line Items]
Loan count	16	21
Consumer | Credit card
Financing Receivable, Modifications [Line Items]
Loan count	96	178
Consumer | Credit card | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	48	134
Consumer | Credit card | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Credit card | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	1
Consumer | Credit card | Other
Financing Receivable, Modifications [Line Items]
Loan count	48	43
Consumer | Home equity lines of credit
Financing Receivable, Modifications [Line Items]
Loan count	1	2
Consumer | Home equity lines of credit | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Home equity lines of credit | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	1
Consumer | Home equity lines of credit | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	1	1
Consumer | Home equity lines of credit | Other
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Personal loans
Financing Receivable, Modifications [Line Items]
Loan count	265	303
Consumer | Personal loans | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	111	183
Consumer | Personal loans | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	111	117
Consumer | Personal loans | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	3	1
Consumer | Personal loans | Other
Financing Receivable, Modifications [Line Items]
Loan count	40	2
Consumer | Auto Loan
Financing Receivable, Modifications [Line Items]
Loan count	130	10
Consumer | Auto Loan | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Auto Loan | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	1	7
Consumer | Auto Loan | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	3
Consumer | Auto Loan | Other
Financing Receivable, Modifications [Line Items]
Loan count	129	0
Consumer | Other
Financing Receivable, Modifications [Line Items]
Loan count	1	8
Consumer | Other | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	1	7
Consumer | Other | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Other | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Consumer | Other | Other
Financing Receivable, Modifications [Line Items]
Loan count	0	1
Leasing
Financing Receivable, Modifications [Line Items]
Loan count	37	2
Leasing | Reduction in interest rate
Financing Receivable, Modifications [Line Items]
Loan count	0	0
Leasing | Extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	2	0
Leasing | Combination of reduction in interest rate and extension of maturity date
Financing Receivable, Modifications [Line Items]
Loan count	1	2
Leasing | Other
Financing Receivable, Modifications [Line Items]
Loan count	34	0