Transfers of financial assets and servicing assets - Key economic assumptions used (Details) - Residential Mortgage	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
BPPR
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Weighted average prepayment speed (annual rate)	6.10%	6.70%
Weighted average life (in years)	9 years 7 months 6 days	8 years 10 months 24 days
Discount rate (annual rate)	9.50%	9.50%
PB
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Weighted average prepayment speed (annual rate)	6.00%	7.30%
Weighted average life (in years)	8 years 9 months 18 days	8 years
Discount rate (annual rate)	12.50%	10.50%