| **Long-term Debt - Table 2 (Details) (USD $)In Millions, unless otherwise specified** | Dec. 31, 2011 | Dec. 31, 2010 |
|---------------------------------------------------------------------------------------|---------------|---------------|
| **Long-term Debt by Maturity**                                                        |          |          |
| Total Long-term Debt                                                                  | $ 1,254.7     | $ 1,511.3     |
| Face Amount [Member]                                                                  |          |          |
| **Long-term Debt by Maturity**                                                        |          |          |
| 2012                                                                                  | 18.9          |          |
| 2013                                                                                  | 18.1          |          |
| 2014                                                                                  | 16.8          |          |
| 2015                                                                                  | 16.9          |          |
| 2016                                                                                  | 184.3         |          |
| Thereafter                                                                            | 1,000.2       |          |
| Total Long-term Debt                                                                  | 1,255.2       |          |
| Net Amount [Member]                                                                   |          |          |
| **Long-term Debt by Maturity**                                                        |          |          |
| 2012                                                                                  | 18.9          |          |
| 2013                                                                                  | 18.1          |          |
| 2014                                                                                  | 16.8          |          |
| 2015                                                                                  | 16.9          |          |
| 2016                                                                                  | 184.3         |          |
| Thereafter                                                                            | 999.7         |          |
| Total Long-term Debt                                                                  | $ 1,254.7     |          |

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| - Definition
Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date. May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.
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| - Definition
Amount of long-term debt maturities after year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.
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Amount of long-term debt maturing within the next twelve months following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.
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Amount of long-term debt maturing in year five following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.
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Amount of long-term debt maturing in year four following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.
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Amount of long-term debt maturing in year three following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed of determinable prices and dates.
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Amount of long-term debt maturing in year two following the date of the latest balance sheet presented in the financial statements, which may include maturities of long-term debt, sinking fund requirements, and other securities redeemable at fixed or determinable prices and dates.
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