Significant Accounting Policies - Accumulated Other Comprehensive Items in Accompanying Consolidated Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Sep. 30, 2013
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Foreign currency translation adjustments at beginning of period	$ 154	$ 167	$ 167
Net foreign currency translation adjustments during the period	(16)		(13)
Foreign currency translation adjustments at end of period	138		154
Unrealized gain on investments at beginning of period	2
Net unrealized gains during the period	2		2
Unrealized gain on investments at end of period	4		2
Pension and other postretirement benefit plans at beginning of period	(53)	(75)	(75)
Net change in pension and other postretirement benefit plans during the period	1	1	22
Pension and other postretirement benefit plans at end of period	(52)		(53)
Total accumulated other comprehensive income	$ 90		$ 103