Contingencies and Commitments - Additional Information - 1 (Detail) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended			3 Months Ended	1 Months Ended			1 Months Ended		3 Months Ended		12 Months Ended			3 Months Ended
	Jan. 31, 2007 D	Mar. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2012 EUR (€)	Mar. 31, 2013 Recurring costs of managing hazardous substances and environmental programs [Member]	Jan. 31, 2007 Spanish Government [Member] Y	Jan. 31, 2007 Tariffs Granted by Spain [Member] USD ($)	Jan. 31, 2007 Tariffs Granted by Spain [Member] EUR (€)	Jun. 30, 2003 Massena West, NY [Member] Y	Nov. 30, 2008 Grasse River [Member] USD ($)	Sep. 30, 2012 Grasse River [Member] USD ($)	Jun. 30, 2012 Grasse River [Member] USD ($)	Dec. 31, 2011 Grasse River [Member] USD ($)	Dec. 31, 2010 Grasse River [Member] USD ($)	Mar. 24, 2010 Grasse River [Member] USD ($)	Jun. 30, 2012 Smelter sites [Member] USD ($)
Loss Contingencies [Line Items]
Number of years operating under a power supply structure						9
Days provided to submit observations and comments to the EC	30
Loss contingency, range of possible loss, maximum			$ 387	€ 303			$ 90	€ 70
Number of cleanup locations		More than 100
Remediation reserve balance		524	532
Remediation reserve balance, classified as a current liability		68	74
Increase and decrease in reserves due to effects of foreign currency translation		2
Payments related to remediation expenses applied against the reserve		5
Percentage of cost of goods sold					2.00%
Period of time between potential phenomenon occurrences, years									10
Remediation reserve increase										40	128	37	1	2		(30)
Remediation reserve adjustment															17
Remediation alternative estimated cost		$ 243