Fair Value Of Financial Instruments (Schedule Of Key Valuation Inputs Used To Measure Fair Value Of Investment In Cell C) (Details) - Cell C [Member] R in Billions, $ in Billions	9 Months Ended	12 Months Ended
	Mar. 31, 2022 USD ($)	Jun. 30, 2021 USD ($)	Mar. 31, 2022 ZAR (R)	Jun. 30, 2021 ZAR (R)
Net adjusted external debt	$ 0.8	$ 0.8	R 11.7	R 11.2
Lease liabilities included in net adjusted external debt			R 0.0	R 0.0
Weighted Average Cost of Capital (WACC) Rate [Member] | Minimum [Member]
Investment fair value measurement inputs	18.00%	18.00%
Weighted Average Cost of Capital (WACC) Rate [Member] | Maximum [Member]
Investment fair value measurement inputs	24.00%	24.00%
Long Term Growth Rate [Member]
Investment fair value measurement inputs	3.00%	3.00%
Marketability Discount [Member]
Investment fair value measurement inputs	10.00%
Minority Discount [Member]
Investment fair value measurement inputs	15.00%