Commitments and Contingencies (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012
Environmental Matters [Member]
Loss Contingencies [Line Items]
Reserve for environmental matters on discount	$ 5		$ 7
Reserve for environmental matters on undiscounted basis	5		7
Cash payments for environmental reserves	2	1
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Cash payments for environmental reserves	2	2
Number of claimants	42,000		42,000
Respirator reserve on discounted basis	11		13
Respirator reserve on undiscounted basis	$ 15		$ 17