XML 402 R163.htm IDEA: XBRL DOCUMENT v3.22.2.2
Post-retirement benefit obligations - Sensitivity Analysis (Details) - ZAR (R)
R in Millions
Jun. 30, 2022
Jun. 30, 2021
Sensitivity analysis    
Cost inflation as premium over CPI 2.00%  
South Africa | Healthcare | Healthcare cost inflation    
Sensitivity analysis    
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 387 R 411
Increase (decrease) in net obligation due to decrease in actuarial assumption R (325) R (344)
South Africa | Healthcare | Discount rate    
Sensitivity analysis    
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 (309) R (329)
Increase (decrease) in net obligation due to decrease in actuarial assumption R 373 R 399
United States | Healthcare | Healthcare cost inflation    
Sensitivity analysis    
Increase in actuarial assumption (as a percent) 1.00% 1.00%
Decrease in actuarial assumption (as a percent) 1.00% 1.00%
United States | Healthcare | Discount rate    
Sensitivity analysis    
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 (21) R (25)
Increase (decrease) in net obligation due to decrease in actuarial assumption R 28 R 34