Risk management - Quantitative SICR thresholds (Details)	Jun. 30, 2025	Dec. 31, 2024
Mortgages \| Investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.9	2.9
Mortgages \| Non-investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.4	2.4
Consumer lending \| Investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.9	2.8
Consumer lending \| Non-investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.2	2.1
Business lending \| Investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.7	2.7
Business lending \| Non-investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.0	2.1
Governments and financial institutions \| Investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.9	2.9
Governments and financial institutions \| Non-investment grade
Disclosure of financial assets [line items]
Average threshold ratio	1.9	1.9
Other Wholesale Banking \| Investment grade
Disclosure of financial assets [line items]
Average threshold ratio	2.7	2.7
Other Wholesale Banking \| Non-investment grade
Disclosure of financial assets [line items]
Average threshold ratio	1.9	1.9