|
Fair Value of Financial Instruments (Carrying Value and Fair Value of Financial Instruments Disclosure) (Details) (USD $)
In Millions |
Jun. 30, 2011
|
Dec. 31, 2010
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|---|---|---|---|---|---|---|
| Long-term debt: | ||||||
| Total long-term debt | $ 3,898.8 | $ 1,713.1 | ||||
|
Term Loan $1.25 Billion [Member] | Carrying Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 1,187.5 | |||||
|
Term Loan $1.25 Billion [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 1,187.5 | |||||
|
Senior Notes $1.3 Billion [Member] | Carrying Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 1,289.1 | 990.3 | ||||
|
Senior Notes $1.3 Billion [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 1,299.9 | 972.5 | ||||
|
Senior Notes $325 Million [Member] | Carrying Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 325.0 | 325.0 | ||||
|
Senior Notes $325 Million [Member] | Fair Value [Member]
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| Long-term debt: | ||||||
| Senior notes | 353.9 | 355.6 | ||||
|
Senior Notes $400 Million [Member] | Carrying Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 397.9 | 397.8 | ||||
|
Senior Notes $400 Million [Member] | Fair Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 430.2 | 422.8 | ||||
|
Senior Notes $700 Million due 2021 [Member] | Carrying Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 699.3 | |||||
|
Senior Notes $700 Million due 2021 [Member] | Fair Value [Member]
|
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| Long-term debt: | ||||||
| Senior notes | 684.0 | |||||
|
Carrying Value [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 60.7 | [1] | 63.2 | [1] | ||
| Long-term debt: | ||||||
| Customer borrowings | 5.1 | 4.0 | ||||
| Total long-term debt | 3,903.9 | 1,717.1 | ||||
|
Carrying Value [Member] | Customer supplemental payments [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 22.3 | 22.3 | ||||
|
Carrying Value [Member] | ArcelorMittal USA-Ispat receivable [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 29.7 | 32.8 | ||||
|
Carrying Value [Member] | Other credit receivable [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 8.7 | 8.1 | ||||
|
Fair Value [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 63.6 | [1] | 66.5 | [1] | ||
| Long-term debt: | ||||||
| Customer borrowings | 5.1 | 4.0 | ||||
| Total long-term debt | 3,960.6 | 1,754.9 | ||||
|
Fair Value [Member] | Customer supplemental payments [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 19.9 | 19.5 | ||||
|
Fair Value [Member] | ArcelorMittal USA-Ispat receivable [Member]
|
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| Long-term receivables: | ||||||
| Receivables | 35.0 | 38.9 | ||||
|
Fair Value [Member] | Other credit receivable [Member]
|
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| Long-term receivables: | ||||||
| Receivables | $ 8.7 | $ 8.1 | ||||
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