Restructuring (Restructuring Activities and Related Reserves) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013 Severance and Employee Benefits [Member]	Jun. 30, 2013 Severance and Employee Benefits [Member]	Jun. 30, 2013 Environmental Remediation [Member]	Mar. 31, 2013 Environmental Remediation [Member]	Jun. 30, 2013 Asset Impairment and Accelerated Depreciation [Member]	Jun. 30, 2013 Asset Impairment and Accelerated Depreciation [Member]	Jun. 30, 2013 Other [Member]	Jun. 30, 2013 Other [Member]
Restructuring Cost and Reserve [Line Items]
Reserve balance	$ 7		$ 5		$ 4	$ 2	$ 1	$ 2			$ 1	$ 2
Charges	5	2	30	14	3	9	1		1	18	1	2
Costs charged against assets / liabilities	(1)		(20)			(1)			(1)	(18)		(1)
Cash paid	(2)		(6)		(2)	(5)						(1)
Reserve balance	$ 9		$ 9		$ 5	$ 5	$ 2	$ 2			$ 2	$ 2