Income Taxes (Uncertain Tax Positions) (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2020		Jun. 30, 2019	Jun. 30, 2018
Change in accrual for uncertain tax positions, excluding interest and penalties
Balance, beginning of year	$ 94		$ 91	$ 110
Additions for prior year tax positions	1		7	1
Additions for current year tax positions	2		9	0
Reduction for prior year tax positions	(24)	[1]	(13)	(20)
Balance, end of year	$ 73		$ 94	$ 91

[1] The reduction for prior year tax positions in fiscal 2020 includes $21 million from the expiration of statutes of limitations.