Pre-Tax Gain (Loss) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Derivative [Line Items]
Total gain (loss)	$ (3)		$ 1	$ (7)
Exchange Contracts
Derivative [Line Items]
Total gain (loss)	(4)	8		1
Forward Contracts
Derivative [Line Items]
Total gain (loss)	(1)	2	(2)	3
Metal Contracts
Derivative [Line Items]
Total gain (loss)	$ 2	$ (10)	$ 3	$ (11)