Transfers of financial assets and servicing assets - Key economic assumptions used (Details) - Residential Mortgage	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
BPPR
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Prepayment speed	7.20%	6.10%
Weighted average life (in years)	9 years 7 months 6 days	9 years 7 months 6 days
Discount rate (annual rate)	9.80%	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]
Prepayment speed	6.30%	6.00%
Weighted average life (in years)	8 years 9 months 18 days	8 years 9 months 18 days
Discount rate (annual rate)	12.90%	12.50%