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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
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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 |  |  |  |  |  |  |  |  |  |  |  |  |  |

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