v3.26.1
Borrowings and lease liabilities - Schedule of borrowings (Details)
$ in Millions, Tsh in Billions
 6 Months Ended 12 Months Ended
Jun. 30, 2026
USD ($)
Jun. 30, 2026
TZS (Tsh)
Jun. 30, 2025
USD ($)
Dec. 31, 2025
USD ($)
Disclosure of detailed information about borrowings [line items]        
Opening balance $ 2,044.0   $ 1,984.0 $ 1,984.0
Proceeds from borrowings 199.0   285.0 285.0
Repayment of borrowings (650.0)   (180.0) (245.0)
Finance costs paid on borrowings (55.0)     (106.0)
Interest charged to the income statement 56.0     4.0
Gain on settlement of bonds (15.0)     0.0
Deferred loan fees (1.0)     111.0
Translation (7.0)     11.0
Closing balance 1,571.0     2,044.0
Non-current 1,559.0     2,025.0
Current 12.0     19.0
Reconciliation of finance costs paid (excluding lease finance costs)        
Finance costs paid on borrowings 55.0     106.0
Interest paid on tax liability 0.0     46.0
Commitment fees, utilisation fees and other borrowing costs 6.0     12.0
Total finance costs paid 61.0   $ 54.0 $ 164.0
Repayments of bonds, notes and debentures 650.0      
Geita Revolving Loan, Facility A        
Disclosure of detailed information about borrowings [line items]        
Proceeds from borrowings 143.8      
Geita Revolving Loan, Facility B        
Disclosure of detailed information about borrowings [line items]        
Proceeds from borrowings 50.0 Tsh 131.5    
2028 Notes        
Reconciliation of finance costs paid (excluding lease finance costs)        
Repayments of bonds, notes and debentures 558.0      
2030 Notes        
Reconciliation of finance costs paid (excluding lease finance costs)        
Repayments of bonds, notes and debentures $ 107.0