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, 2023 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2023 ZAR (R)	Jun. 30, 2022 ZAR (R)
Net adjusted external debt	$ 0.4	$ 0.8	R 8.0	R 13.5
Weighted Average Cost Of Capital (WACC) Rate [Member] \| Minimum [Member]
Investment fair value measurement inputs	20.00%	20.00%
Weighted Average Cost Of Capital (WACC) Rate [Member] \| Maximum [Member]
Investment fair value measurement inputs	31.00%	31.00%
Long Term Growth Rate [Member]
Investment fair value measurement inputs	4.50%	3.00%
Marketability Discount [Member]
Investment fair value measurement inputs	20.00%	10.00%
Minority Discount [Member]
Investment fair value measurement inputs	30.00%	15.00%