Commitments And Contingencies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Sep. 30, 2011
Environmental Matters [Member]
Loss Contingencies [Line Items]
Reserve for environmental matters on discounted and undiscounted basis	$ 6		$ 6
Cash payments for environmental reserves	1	1
Respirator Liabilities [Member]
Loss Contingencies [Line Items]
Number of claimants	42,000		42,000
Respirator reserve on discounted basis	10		11
Respirator reserve on undiscounted basis	15		16
Cash payments for respirator reserves	$ 1	$ 3