v3.26.1
Allowance for expected credit losses - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Financing Receivable, Allowance for Credit Loss [Line Items]          
Allowance for expected credit losses $ 28.4   $ 28.4   $ 27.6
Current expected credit losses $ 0.6 $ 0.0 $ 1.0 $ 0.0  
Credit Rating Agencies | Assets within scope of credit losses | Credit concentration risk          
Financing Receivable, Allowance for Credit Loss [Line Items]          
Concentration risk, percentage     64.00%    
Credit Rating Agencies | Assets within scope of credit losses | Credit concentration risk | A- Or Better Rating          
Financing Receivable, Allowance for Credit Loss [Line Items]          
Concentration risk, percentage     97.00%