v3.26.3
Segment reporting - Reconciliation of information on reportable segments to the amounts reported in the financial statements (Details) - USD ($)
$ in Millions
 1 Months Ended 3 Months Ended 9 Months Ended
Aug. 31, 2026
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Geographical information            
Revenues from external customers   $ 490.5 $ 403.9 $ 1,334.5 $ 1,184.2  
Finance costs   (114.4) (87.1) (313.0) (259.7)  
Finance income   70.8 122.0 218.4 171.6  
Net loss on disposal of subsidiary $ (58.7)          
Income before taxation   90.1 217.5 233.1 409.5  
Segment assets   4,115.3   4,115.3   $ 4,489.6
Total liabilities   4,285.6   4,285.6   $ 4,579.4
Expense from long-term employee benefits due to changes in expected vesting and settlement amounts in connection with merger agreement   39.0 0.0 96.4 0.0  
Costs related to internal reorganization   0.0 1.8 0.0 3.5  
Expenses related to strategic initiatives and operating systems   13.1 0.8 35.9 5.1  
Impairment of assets held for sale   0.0   (75.4) 0.0  
Discontinued operations            
Geographical information            
Revenues from external customers   17.6 51.2 111.8 143.8  
Finance costs   (0.9) (14.6) (26.7) (70.6)  
Finance income   6.0 8.2 19.9 14.7  
Net loss on disposal of subsidiary   (58.7)   (38.7)    
Income before taxation   (40.8) (29.1) (39.6) (84.2)  
Impairment loss       75.4    
Aggregate continuing and discontinuing operations            
Geographical information            
Segment Adjusted EBITDA   305.8 290.8 873.7 854.3  
Unallocated corporate expenses   (23.1) (29.3) (77.0) (91.8)  
Finance costs   (115.3) (101.7) (339.7) (330.3)  
Depreciation and amortization   (54.6) (105.0) (166.6) (283.4)  
Share-based payment expense   (17.1) (6.0) (57.8) (20.0)  
Other costs   (52.2) (13.1) (133.5) (21.7)  
Net impairment of property, plant and equipment, intangible assets excluding goodwill and related prepaid land rent   (2.1) (1.8) (82.5) (5.4)  
Business combination costs   (13.5) (0.1) (29.0) (1.3)  
Insurance claims   0.1 0.1 0.2 0.4  
Net gain/(loss) on disposal of property, plant and equipment and right-of-use assets   0.9 (0.6) 4.3 0.4  
Net impairment reversal of withholding tax receivables   2.3 24.9 1.8 37.8  
Finance income   76.8 130.2 238.3 186.3  
Net loss on disposal of subsidiary   (58.7)   (38.7)    
Cost of sales            
Geographical information            
Net impairment of property, plant and equipment, intangible assets excluding goodwill and related prepaid land rent   (2.1) (1.6) (5.9) (3.4)  
Nigeria            
Geographical information            
Revenues from external customers   359.4 268.0 942.6 799.7  
Nigeria | Aggregate continuing and discontinuing operations            
Geographical information            
Revenues from external customers   359.4 268.0 942.6 799.7  
Segment Adjusted EBITDA   215.0 169.6 564.0 519.2  
SSA            
Geographical information            
Revenues from external customers   131.1 135.9 391.9 384.5  
SSA | Aggregate continuing and discontinuing operations            
Geographical information            
Revenues from external customers   131.1 135.9 391.9 384.5  
Segment Adjusted EBITDA   74.8 80.0 223.3 224.8  
Latam | Discontinued operations            
Geographical information            
Revenues from external customers   17.6 51.2 111.8 143.8  
Latam | Aggregate continuing and discontinuing operations            
Geographical information            
Revenues from external customers   17.6 51.2 111.8 143.8  
Segment Adjusted EBITDA   $ 16.0 $ 41.2 $ 86.4 $ 110.3