Significant Accounting Policies (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Sep. 30, 2011
Inventories [Line Items]
Value of inventories under FIFO method	$ 52	$ 52	$ 53
Decrease in cost of goods sold	(1)	(1)
Increase in net income due to LIFO inventory liquidation	$ 1	$ 1
Effect of LIFO Inventory Liquidation on diluted earnings per share	$ 0.01	$ 0.01