v3.10.0.1
Derivative Financial Assets - Disclosure of Open Position at the Reporting Date (Details)
oz in Thousands, R / kg in Thousands, $ in Millions
Jun. 30, 2018
USD ($)
R / $
R / kg
$ / oz
oz
$ / R
Rand gold hedging contracts | Cash flow hedges  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 300
Price of hedging instrument | R / kg 639
Rand gold hedging contracts | Cash flow hedges | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 54
Price of hedging instrument | R / kg 697
Rand gold hedging contracts | Cash flow hedges | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 51
Price of hedging instrument | R / kg 621
Rand gold hedging contracts | Cash flow hedges | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 53
Price of hedging instrument | R / kg 630
Rand gold hedging contracts | Cash flow hedges | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 41
Price of hedging instrument | R / kg 614
Rand gold hedging contracts | Cash flow hedges | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 43
Price of hedging instrument | R / kg 622
Rand gold hedging contracts | Cash flow hedges | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 34
Price of hedging instrument | R / kg 643
Rand gold hedging contracts | Cash flow hedges | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 15
Price of hedging instrument | R / kg 631
Rand gold hedging contracts | Cash flow hedges | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 9
Price of hedging instrument | R / kg 655
Zero cost collars  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 252
Zero cost collars | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 13.69
Zero cost collars | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 14.54
Zero cost collars | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 94
Zero cost collars | FY19 Q1 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 14.09
Zero cost collars | FY19 Q1 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 15.09
Zero cost collars | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 53
Zero cost collars | FY19 Q2 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 14.14
Zero cost collars | FY19 Q2 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 15.08
Zero cost collars | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 45
Zero cost collars | FY19 Q3 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 13.14
Zero cost collars | FY19 Q3 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 13.80
Zero cost collars | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 60
Zero cost collars | FY19 Q4 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 13.09
Zero cost collars | FY19 Q4 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 13.77
Zero cost collars | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 0
Zero cost collars | FY20 Q1 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q1 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 0
Zero cost collars | FY20 Q2 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q2 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 0
Zero cost collars | FY20 Q3 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q3 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 0
Zero cost collars | FY20 Q4 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Zero cost collars | FY20 Q4 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | R / $ 0.00
Forward contracts  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 273
Price of derivative instrument at fair value through profit and loss | $ / R 13.95
Forward contracts | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 8
Price of derivative instrument at fair value through profit and loss | $ / R 13.55
Forward contracts | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 59
Price of derivative instrument at fair value through profit and loss | $ / R 13.50
Forward contracts | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 69
Price of derivative instrument at fair value through profit and loss | $ / R 13.63
Forward contracts | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 65
Price of derivative instrument at fair value through profit and loss | $ / R 13.76
Forward contracts | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 18
Price of derivative instrument at fair value through profit and loss | $ / R 14.59
Forward contracts | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 18
Price of derivative instrument at fair value through profit and loss | $ / R 14.76
Forward contracts | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 18
Price of derivative instrument at fair value through profit and loss | $ / R 14.94
Forward contracts | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, notional amount | $ $ 18
Price of derivative instrument at fair value through profit and loss | $ / R 15.12
US gold derivative contracts  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 96
Price of derivative instrument at fair value through profit and loss | $ / oz 1,318
US gold derivative contracts | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 24
Price of derivative instrument at fair value through profit and loss | $ / oz 1,288
US gold derivative contracts | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 24
Price of derivative instrument at fair value through profit and loss | $ / oz 1,291
US gold derivative contracts | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 20
Price of derivative instrument at fair value through profit and loss | $ / oz 1,335
US gold derivative contracts | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 18
Price of derivative instrument at fair value through profit and loss | $ / oz 1,338
US gold derivative contracts | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 6
Price of derivative instrument at fair value through profit and loss | $ / oz 1,370
US gold derivative contracts | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 4
Price of derivative instrument at fair value through profit and loss | $ / oz 1,400
US gold derivative contracts | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 0
Price of derivative instrument at fair value through profit and loss | $ / oz 0
US gold derivative contracts | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 0
Price of derivative instrument at fair value through profit and loss | $ / oz 0
Gold derivative contracts  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 396
Gold derivative contracts | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 78
Gold derivative contracts | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 75
Gold derivative contracts | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 73
Gold derivative contracts | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 59
Gold derivative contracts | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 49
Gold derivative contracts | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 38
Gold derivative contracts | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 15
Gold derivative contracts | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 9
US silver derivative contracts  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 750
US silver derivative contracts | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.19
US silver derivative contracts | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.19
US silver derivative contracts | FY19 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 240
US silver derivative contracts | FY19 Q1 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.10
US silver derivative contracts | FY19 Q1 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.10
US silver derivative contracts | FY19 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 240
US silver derivative contracts | FY19 Q2 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.10
US silver derivative contracts | FY19 Q2 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.10
US silver derivative contracts | FY19 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 90
US silver derivative contracts | FY19 Q3 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.30
US silver derivative contracts | FY19 Q3 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.30
US silver derivative contracts | FY19 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 90
US silver derivative contracts | FY19 Q4 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.30
US silver derivative contracts | FY19 Q4 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.30
US silver derivative contracts | FY20 Q1  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 90
US silver derivative contracts | FY20 Q1 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 17.40
US silver derivative contracts | FY20 Q1 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 18.40
US silver derivative contracts | FY20 Q2  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 0
US silver derivative contracts | FY20 Q2 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00
US silver derivative contracts | FY20 Q2 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00
US silver derivative contracts | FY20 Q3  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 0
US silver derivative contracts | FY20 Q3 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00
US silver derivative contracts | FY20 Q3 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00
US silver derivative contracts | FY20 Q4  
Disclosure of detailed information about financial instruments [line items]  
Derivative, nonmonetary notional amount (oz) 0
US silver derivative contracts | FY20 Q4 | Floor  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00
US silver derivative contracts | FY20 Q4 | Cap  
Disclosure of detailed information about financial instruments [line items]  
Price of derivative instrument at fair value through profit and loss | $ / oz 0.00