Post-retirement benefit obligations - Reconciliation (Details) - Healthcare - Benefit obligation - ZAR (R) R in Millions	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019
Reconciliation of total post-retirement health care obligation recognized in the statement of financial position
Beginning balance	R 4,093	R 4,243
Movements recognised in the income statement:	467	485
current service cost	63	66
interest cost	404	420
curtailments and settlements		(1)
Actuarial (gains) losses recognised in other comprehensive income:	(1,040)	(460)
arising from changes in financial assumptions	(982)	(286)
arising from changes in demographic assumptions	(3)
arising from change in actuarial experience	(55)	(174)
Benefits paid	(202)	(181)
Transferred to held for sale assets	(8)
Translation of foreign operations	67	6
Ending balance	3,377	4,093
South Africa
Reconciliation of total post-retirement health care obligation recognized in the statement of financial position
Beginning balance	3,825	3,995
Movements recognised in the income statement:	440	459
current service cost	45	53
interest cost	395	407
curtailments and settlements		(1)
Actuarial (gains) losses recognised in other comprehensive income:	(1,085)	(468)
arising from changes in financial assumptions	(1,026)	(293)
arising from change in actuarial experience	(59)	(175)
Benefits paid	(180)	(161)
Transferred to held for sale assets	(8)
Ending balance	2,992	3,825
US
Reconciliation of total post-retirement health care obligation recognized in the statement of financial position
Beginning balance	268	248
Movements recognised in the income statement:	27	26
current service cost	18	13
interest cost	9	13
Actuarial (gains) losses recognised in other comprehensive income:	45	8
arising from changes in financial assumptions	44	7
arising from changes in demographic assumptions	(3)
arising from change in actuarial experience	4	1
Benefits paid	(22)	(20)
Translation of foreign operations	67	6
Ending balance	R 385	R 268

The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in demographic assumptions that result in remeasurements of the net defined benefit liability (asset). Demographic assumptions deal with matters such as: (a) mortality; (b) rates of employee turnover, disability and early retirement; (c) the proportion of plan members with dependants who will be eligible for benefits; (d) the proportion of plan members who will select each form of payment option available under the plan terms; and (e) claim rates under medical plans. [Refer: Net defined benefit liability (asset)]

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The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from changes in financial assumptions that result in remeasurements of the net defined benefit liability (asset). Financial assumptions deal with items such as: (a) the discount rate; (b) benefit levels, excluding any cost of the benefits to be met by employees, and future salary; (c) in the case of medical benefits, future medical costs, including claim handling costs (ie the costs that will be incurred in processing and resolving claims, including legal and adjuster's fees); and (d) taxes payable by the plan on contributions relating to service before the reporting date or on benefits resulting from that service. [Refer: Net defined benefit liability (asset)]

+ References

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The decrease (increase) in a net defined benefit liability (asset) resulting from actuarial gains (losses) arising from experience adjustments that result in remeasurements of the net defined benefit liability (asset). Experience adjustments deal with the effects of differences between the previous actuarial assumptions and what has actually occurred. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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The increase (decrease) in the net defined benefit liability (asset) resulting from employee service in the current period. [Refer: Net defined benefit liability (asset)]

+ References

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The decrease (increase) in a net defined benefit liability (asset) resulting from the remeasurement of that net defined benefit liability (asset). [Refer: Net defined benefit liability (asset)]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from changes in foreign exchange rates. [Refer: Net defined benefit liability (asset)]

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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The increase (decrease) in the net defined benefit liability (asset) resulting from the passage of time. [Refer: Interest expense; Net defined benefit liability (asset)]

+ References

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The amount of deficit or surplus in a defined benefit plan, adjusted for any effect of limiting a net defined benefit asset to the asset ceiling. [Refer: Defined benefit plans [member]]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from past service cost and gains (losses) arising from settlements. [Refer: Gains (losses) arising from settlements, net defined benefit liability (asset); Net defined benefit liability (asset)]

+ References

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The decrease (increase) in the net defined benefit liability (asset) resulting from payments from the plan. [Refer: Net defined benefit liability (asset)]

+ References

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The increase (decrease) in the net defined benefit liability (asset) resulting from amounts recorded in the income statement in the current period.

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The amount of net defined benefit liability (asset) transferred to assets held for sale.

+ References

No definition available.

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