Venezuela - Additional Information (Detail) In Millions, unless otherwise specified	12 Months Ended									12 Months Ended			3 Months Ended	12 Months Ended
	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2012 USD ($)	Sep. 30, 2014 VEF	Mar. 31, 2014	Sep. 30, 2014 Maximum [Member] USD ($)	Sep. 30, 2014 Operating Affiliate, Venezuela [Member]	Sep. 30, 2014 SICAD 2 Currency Exchange Mechanism [Member]	Mar. 31, 2014 SICAD 2 Currency Exchange Mechanism [Member]	Sep. 30, 2014 Subsidiaries [Member] USD ($)	Sep. 30, 2013 Subsidiaries [Member] USD ($)	Sep. 30, 2012 Subsidiaries [Member] USD ($)	Mar. 31, 2014 Operating Affiliate [Member] USD ($)	Sep. 30, 2014 Operating Affiliate [Member] Operating Affiliate, Venezuela [Member] USD ($)
Nature Of Operations [Line Items]
Equity method investment, ownership percentage							49.00%
Operating affiliate investment	$ 17
Due from affiliates, dividends cash				19		1
Cash dividends received from subsidiary										5	3	6
Conversion of Bolivars to USD					6.3			50.0	50.8
Negative impact of exchange rate devaluation	4													8
Currency denomination, remeasurement loss													2
Tax benefit due to reduction of deferred tax liability	$ 8	$ (9)	$ (6)										$ 2