REVENUE - Market Risk (Details) - Commodity price sensitivity [member] - ZAR (R) R in Millions	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Percentage decrease [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Gains (losses) from change in fair value of derivatives recognised in proift and loss	R (249.0)	R (234.0)	R (243.3)
Percentage increase [member]
Disclosure of nature and extent of risks arising from financial instruments [line items]
Gains (losses) from change in fair value of derivatives recognised in proift and loss	R 249.0	R 234.0	R 243.3

The gains (losses) resulting from change in the fair value of derivatives recognised in profit or loss. [Refer: Derivatives [member]]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 1
-IssueDate 2017-01-01
-Paragraph 85
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=1&date=2017-03-01&anchor=para_85&doctype=Standard
-URIDate 2017-03-09

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Namespace Prefix:	ifrs-full_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration