XML 332 R201.htm IDEA: XBRL DOCUMENT v3.19.3
Financial risk management and financial instruments - Foreign Currency Risk (Details)
€ in Millions, R in Millions, $ in Millions
12 Months Ended
Jun. 30, 2019
USD ($)
Jun. 30, 2019
ZAR (R)
Jun. 30, 2018
EUR (€)
Jun. 30, 2018
USD ($)
Jun. 30, 2018
ZAR (R)
Zero-cost collar          
Financial risk management and financial instruments          
Period of foreign currency exposure hedged 12 months        
Notional amount $ 4,000     $ 4,000  
Zero-cost collar | Maximum          
Financial risk management and financial instruments          
Maturity period of derivatives 1 year        
Foreign exchange contracts          
Financial risk management and financial instruments          
Notional amount $ 146     226  
Foreign exchange contracts | Cash flow hedge | Rand          
Financial risk management and financial instruments          
Notional amount | R   R 0     R 33
Foreign exchange contracts | Cash flow hedge | US Dollar          
Financial risk management and financial instruments          
Notional amount       $ 0  
Foreign exchange contracts | Cash flow hedge | Euro          
Financial risk management and financial instruments          
Notional amount | €     € 2.1