v3.26.1
Segment reporting - Reconciliation of information on reportable segments to the amounts reported in the financial statements (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Geographical information      
Revenues from external customers $ 415.4 $ 392.1 [1]  
Finance costs (110.7) (93.1) [1]  
Finance income 116.6 18.3 [1]  
Income before taxation 117.2 91.0 [1]  
Segment assets 4,665.7   $ 4,489.6
Total liabilities 4,689.4   $ 4,579.4
Expense from long-term employee benefits due to changes in expected vesting and settlement amounts in connection with merger agreement 17.5 0.0  
Expenses related to strategic initiatives and operating systems 7.0 1.5  
Discontinued operations      
Geographical information      
Revenues from external customers 51.8 47.5  
Finance costs (14.3) (21.2)  
Finance income 9.9 2.2  
Income before taxation 2.8 (21.8)  
Impairment loss 29.9 0.0  
Aggregate continuing and discontinuing operations      
Geographical information      
Segment Adjusted EBITDA 297.8 286.5  
Unallocated corporate expenses (29.1) (33.9)  
Finance costs (125.0) (114.3)  
Depreciation and amortization (55.8) (89.4)  
Share-based payment expense (23.9) (5.5)  
Other costs (24.5) (3.1)  
Net impairment of property, plant and equipment, intangible assets excluding goodwill and related prepaid land rent (32.8) (2.0)  
Business combination costs (9.2) (0.9)  
Insurance claims   0.1  
Net gain/(loss) on disposal of property, plant and equipment and right-of-use assets 1.5 (1.2)  
Net impairment loss/(reversal) of withholding tax receivables (5.5) 12.4  
Finance income 126.5 20.5  
Cost of sales      
Geographical information      
Net impairment of property, plant and equipment, intangible assets excluding goodwill and related prepaid land rent (2.4) (0.9)  
Nigeria      
Geographical information      
Revenues from external customers 285.0 271.4  
Nigeria | Aggregate continuing and discontinuing operations      
Geographical information      
Revenues from external customers 285.0 271.4  
Segment Adjusted EBITDA 182.6 179.2  
SSA      
Geographical information      
Revenues from external customers 130.4 120.7  
SSA | Aggregate continuing and discontinuing operations      
Geographical information      
Revenues from external customers 130.4 120.7  
Segment Adjusted EBITDA 77.6 71.7  
Latam | Discontinued operations      
Geographical information      
Revenues from external customers 51.8 47.5  
Latam | Aggregate continuing and discontinuing operations      
Geographical information      
Revenues from external customers 51.8 47.5  
Segment Adjusted EBITDA $ 37.6 $ 35.6  
[1] The results for the three months ended March 31, 2025 have been re-presented to reflect that the results of the Latam segment are now reported as a discontinued operation. See note 20.1 for more information.