Leases (Summary of Lease Costs and Supplemental Cash Flows Information) (Parenthetical) (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
		Mar. 31, 2020	Mar. 31, 2020
Lease Costs [Abstract]
Lease costs	[1]	$ 34	$ 95
Sublease income		$ 15	$ 40

[1] Total lease costs of $34 million and $95 million for the three and nine months ended March 31, 2020, respectively, are net of sublease income of approximately $15 million and $40 million, respectively.