v3.26.1
Segment reporting - Summarized segment assets and liabilities and additions (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Disclosure of operating segments [line items]      
Segment assets $ 4,665.7   $ 4,489.6
Total liabilities 4,689.4   $ 4,579.4
Additions of property, plant and equipment, right of use assets and intangible assets 47.3 $ 56.8  
Operating segments      
Disclosure of operating segments [line items]      
Additions of property, plant and equipment, right of use assets and intangible assets 47.3 56.4  
Unallocated items      
Disclosure of operating segments [line items]      
Additions of property, plant and equipment, right of use assets and intangible assets   0.4  
Nigeria | Operating segments      
Disclosure of operating segments [line items]      
Additions of property, plant and equipment, right of use assets and intangible assets 17.4 1.6  
SSA | Operating segments      
Disclosure of operating segments [line items]      
Additions of property, plant and equipment, right of use assets and intangible assets 8.4 18.7  
Latam | Operating segments      
Disclosure of operating segments [line items]      
Additions of property, plant and equipment, right of use assets and intangible assets $ 21.5 $ 36.1