v3.26.1
Post-retirement benefit obligations - Sensitivity analysis (Details) - Pension - ZAR (R)
R in Millions
Jun. 30, 2026
Jun. 30, 2025
South Africa | Salary increase    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R 5 R 6
Increase (decrease) in net obligation due to decrease in actuarial assumption R (4) R (5)
South Africa | Discount rate    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R (1,508) R (1,443)
Increase (decrease) in net obligation due to decrease in actuarial assumption R 1,805 R 1,722
South Africa | Pension increase    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R 1,855 R 1,770
Increase (decrease) in net obligation due to decrease in actuarial assumption R (1,581) R (1,513)
Foreign Countries | Salary increase    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R 200 R 247
Increase (decrease) in net obligation due to decrease in actuarial assumption R (175) R (215)
Foreign Countries | Discount rate    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R (1,141) R (1,212)
Increase (decrease) in net obligation due to decrease in actuarial assumption R 1,402 R 1,473
Foreign Countries | Pension increase    
Disclosure of sensitivity analysis for actuarial assumptions    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
Increase (decrease) in net obligation due to increase in actuarial assumption R 758 R 821
Increase (decrease) in net obligation due to decrease in actuarial assumption R (639) R (689)