Pension and Other Postretirement Benefits (Schedule of Amounts Recognized in Balance Sheets) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Net amount recognized	$ (598)
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension assets	4	$ 0
Accrued pension liabilities	(500)	(621)
Net amount recognized	(496)	(621)
Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Pension assets	0	0
Accrued pension liabilities	(98)	(104)
Net amount recognized	$ (98)	$ (104)