Segment Data - Revenues by Geographic Areas (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	$ 3,035	$ 3,198	$ 8,927	$ 9,252
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	1,603	1,735	4,859	5,145
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Total Revenues	$ 1,433	$ 1,463	$ 4,068	$ 4,107