Segment Information - Revenue and Long-Lived Assets by Geographic Region (Parenthetical) (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	$ 2,080	$ 1,978	$ 2,116	$ 1,965	$ 2,226	$ 1,891	$ 2,161	$ 2,014	$ 8,139	$ 8,292	$ 8,524
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues									3,700	3,800	3,600
U.K. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues									1,300	1,500	1,600
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues									$ 2,300	$ 2,300	$ 2,300