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Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended |  |  | 3 Months Ended | 6 Months Ended |  | 6 Months Ended | 3 Months Ended |  | 6 Months Ended |  | 6 Months Ended | 3 Months Ended |  |  |  |  | 6 Months Ended
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Jun. 30, 2013 SecurityLoan D | Mar. 31, 2013 Agreement | Jun. 30, 2013 D | Jun. 30, 2012 | Jan. 31, 2013 | Jan. 31, 2012 | Jun. 30, 2013 Credit Facility Maturing March 2014 [Member] | Mar. 31, 2013 Aluminio [Member] D | Jun. 30, 2013 6% Notes, Due 2013 [Member] | May 31, 2013 6% Notes, Due 2013 [Member] | Jun. 30, 2013 Debt Accrued And Unpaid Interest [Member] | Mar. 31, 2013 Term Loan Agreement [Member] | Mar. 31, 2013 Term Loan Agreement [Member] First Loans Agreement [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] | Mar. 31, 2013 Revolving Credit Agreement [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] First Loans Agreement [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] First Credit Facility [Member] | Mar. 31, 2013 Revolving Credit Agreement [Member] First Credit Facility [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] Second Credit Facility [Member] | Mar. 31, 2013 Revolving Credit Agreement [Member] Second Credit Facility [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] Third Credit Facility [Member] | Mar. 31, 2013 Revolving Credit Agreement [Member] Third Credit Facility [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] Second Loans Agreement [Member] | Jun. 30, 2013 Revolving Credit Agreement [Member] Third Loans Agreement [Member]
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Early repayment of outstanding notes |  |  |  |  |  |  |  |  |  | $ 422 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Long-term debt, interest rate |  |  |  |  |  | 6.00% |  |  |  | 6.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, amount outstanding |  | 200 | 1,647 | 659 |  |  |  | 52 | 435 |  | 12 | 200 |  |  |  |  |  |  |  |  |  |  |  |
Purchase premiums repaid recorded as interest expense |  |  | 1 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility amount outstanding |  |  |  |  | 150 |  |  | 52 |  |  |  | 200 | 200 |  |  |  |  |  |  |  |  |  |  |
Repayment of credit facility |  |  |  |  |  |  | 150 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Borrowing under revolving credit facility |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 200 | 200 |  |  |  |  |  |
Agreed credit facility amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 150 | 150 | 75 | 75 |  |
Number of agreements |  | 3 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Line of credit facility, amount outstanding |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 200 |  |  |  |  |  |  |  |  |
Line of credit facility, expiration date |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Jul. 31, 2013 |  |  |  |  |  |  | Feb. 28, 2014 | Dec. 31, 2013
Revolving credit facility, term |  |  |  |  |  |  |  |  |  |  |  |  |  | 5 years |  |  |  |  |  |  |  |  |  |
Number of borrowing arrangements | 6 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of active borrowing arrangements | 4 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of terminated borrowing arrangements | 2 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted-average interest rate | 1.58% |  | 1.50% |  |  |  |  | 0.72% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted-average days outstanding | 40 |  | 72 |  |  |  |  | 70 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Weighted average interest rate, outstanding borrowings. + References No definition available. + Details
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- Definition Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 20 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 + Details
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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Details
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- Definition Amount of the cost of borrowed funds accounted for as interest expense for debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.8) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 + Details
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- Definition Amount borrowed under the credit facility as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Date the credit facility terminates, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b),22(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 22 -Article 5 + Details
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- Definition Amount of cash inflow from contractual arrangement with the lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(f)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph f -Article 4 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585 + Details
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