Restructuring - Restructuring Activities and Related Reserves (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Restructuring Cost and Reserve [Line Items]
Reserve balance	$ 10	$ 5
Charges	29	35	15
Costs charged against assets and other	(4)	(21)
Cash paid	(15)	(9)
Foreign currency translation adjustment	(1)
Reserve balance	19	10	5
Severance and Employee Benefits [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	7	2
Charges	18	11
Cash paid	(8)	(6)
Foreign currency translation adjustment	(1)
Reserve balance	16	7
Environmental Remediation [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	2	1
Charges	1	1
Cash paid	(1)
Reserve balance	2	2
Asset Impairment and Accelerated Depreciation [Member]
Restructuring Cost and Reserve [Line Items]
Charges	4	19
Costs charged against assets and other	(4)	(19)
Asset Sales [Member]
Restructuring Cost and Reserve [Line Items]
Charges	1
Cash paid	(1)
Other [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	1	2
Charges	5	4
Costs charged against assets and other		(2)
Cash paid	(5)	(3)
Reserve balance	$ 1	$ 1