Net Recognized Gains (Losses) on Equity Investments (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]
Net realized gains (losses) on investments sold	$ (5)	$ 5	$ 70	$ 238
Net unrealized gains (losses) on investments still held	(22)	50	33	241
Total	(101)	44	4	381
Equity Securities
Schedule Of Gain Loss On Investments Including Marketable Securities And Investments Held At Cost Income Statement Reported Amounts Summary [Line Items]
Other-than-temporary impairments of investments	(69)	(7)	(100)	(10)
Total	$ (96)	$ 48	$ 3	$ 469