Segment Information - Revenue and Long-Lived Assets by Geographic Region (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Total Revenues	$ 2,693	$ 2,093	$ 2,180	$ 2,058	$ 2,080	$ 1,978	$ 2,116	$ 1,965	$ 9,024	$ 8,139	$ 8,292
United States [Member]
Segment Reporting Information [Line Items]
Total Revenues									3,900	3,700	3,800
U.K. [Member]
Segment Reporting Information [Line Items]
Total Revenues									1,400	1,300	1,500
Australia [Member]
Segment Reporting Information [Line Items]
Total Revenues									$ 2,900	$ 2,300	$ 2,300