Financial Instruments (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Sep. 30, 2011
Short-term debt	$ 21	$ 83
Long-term debt	982	844
Foreign exchange forward contracts (asset)	2	0
Fair Value, Inputs, Level 1 [Member]
Short-term debt	0
Long-term debt	0
Foreign exchange forward contracts (asset)	0
Fair Value, Inputs, Level 2 [Member]
Short-term debt	21
Long-term debt	982
Foreign exchange forward contracts (asset)	2
Fair Value, Inputs, Level 3 [Member]
Short-term debt	0
Long-term debt	0
Foreign exchange forward contracts (asset)	$ 0