Segment Information (Summary of Revenues by Segment by Component to Consolidated) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenues	$ 2,513	$ 2,752	$ 3,583	$ 2,541	$ 2,394	$ 2,463	$ 3,108	$ 2,188	$ 11,389	$ 10,153	$ 9,921
Operating Segments | Cable Network Programming Segment
Disaggregation Of Revenue [Line Items]
Revenues									5,381	5,049	4,323
Operating Segments | Cable Network Programming Segment | Affiliate Fee
Disaggregation Of Revenue [Line Items]
Revenues									3,804	3,541	3,059
Operating Segments | Cable Network Programming Segment | Advertising
Disaggregation Of Revenue [Line Items]
Revenues									1,184	1,120	1,075
Operating Segments | Cable Network Programming Segment | Other
Disaggregation Of Revenue [Line Items]
Revenues									393	388	189
Operating Segments | Television Segment
Disaggregation Of Revenue [Line Items]
Revenues									5,979	5,106	5,600
Operating Segments | Television Segment | Affiliate Fee
Disaggregation Of Revenue [Line Items]
Revenues									1,708	1,382	1,235
Operating Segments | Television Segment | Advertising
Disaggregation Of Revenue [Line Items]
Revenues									3,872	3,478	4,076
Operating Segments | Television Segment | Other
Disaggregation Of Revenue [Line Items]
Revenues									399	246	289
Other, Corporate and Eliminations Segment
Disaggregation Of Revenue [Line Items]
Revenues									$ 29	$ (2)	$ (2)