|
Fair Value Of Financial Instruments (Carrying Value And Fair Value Of Financial Instruments Disclosure) (Details) (USD $)
In Millions, unless otherwise specified |
Mar. 31, 2012
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Dec. 31, 2011
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|---|---|---|---|---|---|---|
| Long-term debt: | ||||||
| Total long-term debt | $ 3,583.8 | $ 3,608.7 | ||||
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Carrying Value [Member]
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| Long-term receivables: | ||||||
| Receivables | 57.9 | [1] | 58.8 | [1] | ||
| Long-term debt: | ||||||
| Customer borrowings | 4.6 | 5.1 | ||||
| Total long-term debt | 3,588.4 | 3,613.8 | ||||
|
Carrying Value [Member] | Customer Supplemental Payments [Member]
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| Long-term receivables: | ||||||
| Receivables | 22.3 | 22.3 | ||||
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Carrying Value [Member] | ArcelorMittal USA - Receivable [Member]
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| Long-term receivables: | ||||||
| Receivables | 24.8 | 26.5 | ||||
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Carrying Value [Member] | Other Credit Receivable [Member]
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| Long-term receivables: | ||||||
| Receivables | 10.8 | 10.0 | ||||
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Fair Value [Member]
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| Long-term receivables: | ||||||
| Receivables | 60.6 | [1] | 61.5 | [1] | ||
| Long-term debt: | ||||||
| Customer borrowings | 4.6 | 5.1 | ||||
| Long-term debt noncurrent fair value | 3,862.1 | 3,825.6 | ||||
|
Fair Value [Member] | Customer Supplemental Payments [Member]
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| Long-term receivables: | ||||||
| Receivables | 21.2 | 20.8 | ||||
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Fair Value [Member] | ArcelorMittal USA - Receivable [Member]
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| Long-term receivables: | ||||||
| Receivables | 28.6 | 30.7 | ||||
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Fair Value [Member] | Other Credit Receivable [Member]
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| Long-term receivables: | ||||||
| Receivables | 10.8 | 10.0 | ||||
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Term Loan - $1.25 Billion [Member]
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| Long-term debt: | ||||||
| Term loan | 1,250.0 | 1,250.0 | ||||
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Term Loan - $1.25 Billion [Member] | Carrying Value [Member]
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| Long-term debt: | ||||||
| Term loan | 872.2 | 897.2 | ||||
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Term Loan - $1.25 Billion [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Term loan | 872.2 | 897.2 | ||||
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Senior Notes - $700 Million [Member]
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| Long-term debt: | ||||||
| Senior notes | 700.0 | 700.0 | ||||
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Senior Notes - $700 Million [Member] | Carrying Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 699.3 | 699.3 | ||||
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Senior Notes - $700 Million [Member] | Fair Value [Member]
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||||||
| Long-term debt: | ||||||
| Senior notes | 738.7 | 726.4 | ||||
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Senior Notes - $1.3 Billion [Member]
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| Long-term debt: | ||||||
| Senior notes | 1,300.0 | 1,300.0 | ||||
|
Senior Notes - $1.3 Billion [Member] | Carrying Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 1,289.2 | 1,289.2 | ||||
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Senior Notes - $1.3 Billion [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 1,439.1 | 1,399.4 | ||||
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Senior Notes - $400 Million [Member]
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| Long-term debt: | ||||||
| Senior notes | 400.0 | 400.0 | ||||
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Senior Notes - $400 Million [Member] | Carrying Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 398.1 | 398.0 | ||||
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Senior Notes - $400 Million [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 453.6 | 448.8 | ||||
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Senior Notes - $325 Million [Member]
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| Long-term debt: | ||||||
| Senior notes | 325.0 | 325.0 | ||||
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Senior Notes - $325 Million [Member] | Carrying Value [Member]
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||||||
| Long-term debt: | ||||||
| Senior notes | 325.0 | 325.0 | ||||
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Senior Notes - $325 Million [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | $ 353.9 | $ 348.7 | ||||
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