v3.25.4
Significant accounting policies - Fair value measurement (Details) - SEK (kr)
kr in Millions
12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value kr 343,254 kr 360,634
Financial liabilities at fair value 314,304 330,209
Level 3 | Bottom of range    
Disclosure of fair value measurement of assets [line items]    
Effect of changing the non-observable parameters (10) (16)
Level 3 | Top of range    
Disclosure of fair value measurement of assets [line items]    
Effect of changing the non-observable parameters 10 16
At fair value | Level 2    
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value 41,000 45,000
Financial liabilities at fair value kr 22,000 kr 18,000
Percentage of total financial assets 12.00% 13.00%
Percentage of total financial liabilities 7.00% 6.00%
At fair value | Level 3    
Disclosure of fair value measurement of assets [line items]    
Financial assets at fair value kr 0 kr 0
Financial liabilities at fair value kr 4,000 kr 5,000
Percentage of total financial assets 0.00% 0.00%
Percentage of total financial liabilities 1.00% 1.00%