v3.26.1
Financial assets and liabilities at fair value - Narrative (Details)
6 Months Ended 12 Months Ended
Jun. 30, 2026
SEK (kr)
Dec. 31, 2025
SEK (kr)
Disclosure of detailed information about financial instruments [line items]    
Transfers into Level 3 of fair value hierarchy, assets   kr 0
Transfers into Level 3 of fair value hierarchy, liabilities   kr 0
Sensitivity, correlations maximum positive relationship 1  
Sensitivity correlations maximum negative relationship (1)  
Correlation input    
Disclosure of detailed information about financial instruments [line items]    
Sensitivity, input depreciation, assets 0.12  
Sensitivity, input appreciation, assets 0.12  
Sensitivity, input depreciation, liabilities 0.12  
Sensitivity, input appreciation, liabilities 0.12  
Credit spread, measurement input    
Disclosure of detailed information about financial instruments [line items]    
Sensitivity, input depreciation, assets 0.10%  
Sensitivity, input appreciation, assets 0.10%  
Sensitivity, input appreciation, liabilities 0.10%  
Sensitivity, input depreciation, liabilities 0.10%  
Debt securities issued    
Disclosure of detailed information about financial instruments [line items]    
Transfers from Level 3 kr 346,000,000  
Derivatives    
Disclosure of detailed information about financial instruments [line items]    
Transfers from Level 3 58,000,000  
Other interest-bearing securities except loans    
Disclosure of detailed information about financial instruments [line items]    
Transfers out of Level 1 into Level 2 of fair value hierarchy, assets held at end of reporting period kr 128,000,000