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PROVISIONS - Narrative (Details) - Environmental rehabilitation - USD ($)
$ in Millions
3 Months Ended 12 Months Ended
Dec. 31, 2019
Dec. 31, 2019
Disclosure of other provisions [line items]    
Increase in other provisions $ (511) $ 241
Discount rate change (as percent)   1.00%
Expected decrease in other provisions with 1% increase in discount rate   $ (357)
Expected increase in other provisions with 1% decrease in discount rate   $ 207