Pension and Other Postretirement Benefits-Defined Contribution Plans (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Compensation And Retirement Disclosure [Abstract]
Defined Contribution plans, employer contribution	$ 44	$ 39	$ 38

Amount of discretionary contributions made by an employer to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration