Contingencies and Commitments - Additional Information - 1 (Detail) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended				9 Months Ended			1 Months Ended			1 Months Ended			3 Months Ended			9 Months Ended	12 Months Ended		3 Months Ended		9 Months Ended
	Jan. 31, 2007	Sep. 30, 2013 USD ($)	Sep. 30, 2013 USD ($)	Dec. 31, 2012 USD ($)	Jun. 30, 2012 USD ($)	Jun. 30, 2012 EUR (€)	Sep. 30, 2013 Minimum [Member]	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Recurring Costs of Managing Hazardous Substances and Environmental Programs [Member]	Jan. 31, 2007 Spanish Government [Member]	Jan. 31, 2007 Tariffs Granted by Spain [Member] USD ($)	Jan. 31, 2007 Tariffs Granted by Spain [Member] EUR (€)	Jun. 30, 2003 Massena West, NY [Member]	Mar. 24, 2010 Grasse River [Member] USD ($)	Nov. 30, 2008 Grasse River [Member] USD ($)	Sep. 30, 2013 Grasse River [Member] USD ($)	Sep. 30, 2012 Grasse River [Member] USD ($)	Jun. 30, 2012 Grasse River [Member] USD ($)	Sep. 30, 2013 Grasse River [Member] USD ($)	Dec. 31, 2011 Grasse River [Member] USD ($)	Dec. 31, 2010 Grasse River [Member] USD ($)	Jun. 30, 2012 Smelter Sites [Member] USD ($)	Sep. 30, 2013 Massena West NY and Baie Comeau Quebec Canada [Member] USD ($)	Sep. 30, 2013 Massena West NY and Baie Comeau Quebec Canada [Member] USD ($)
Loss Contingencies [Line Items]
Number of years operating under a power supply structure										9 years
Days provided to submit observations and comments to the EC	30 days
Loss contingency, range of possible loss, maximum					$ 403	€ 303					$ 90	€ 70
Number of cleanup locations			More than 100
Remediation reserve balance		515	515	532
Remediation reserve balance, classified as a current liability		51	51	74
Remediation reserve increase															40	1	128	37	17	1	2	(30)
Remediation reserve adjustment														17									0	12
Increase and decrease in reserves due to effects of foreign currency translation		1	1
Payments related to remediation expenses applied against the reserve		22	33
Percentage of cost of goods sold									2.00%
Period of time between potential phenomenon occurrences, years													10 years
Remediation alternative estimated cost			$ 243
Planning and design phase period							2 years	3 years
Actual remediation fieldwork period			4 years