| **Fair Value Measurements - Table 1 (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions** | Sep. 30, 2016 | Dec. 31, 2015 |
|------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
| Market Approach Valuation Technique [Member]                                                                           |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Current portion of restricted marketable securities                                                                    | $ 24.2        | $ 16.1        |
| Noncurrent portion of restricted marketable securities                                                                 | 33.3          | 40.1          |
| Market Approach Valuation Technique [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Current portion of restricted marketable securities                                                                    | 0.0           | 0.0           |
| Noncurrent portion of restricted marketable securities                                                                 | 0.0           | 0.0           |
| Market Approach Valuation Technique [Member] | Significant Other Observable Inputs (Level 2) [Member]                  |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Current portion of restricted marketable securities                                                                    | 24.2          | 16.1          |
| Noncurrent portion of restricted marketable securities                                                                 | 33.3          | 40.1          |
| Market Approach Valuation Technique [Member] | Significant Unobservable Inputs (Level 3) [Member]                      |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Current portion of restricted marketable securities                                                                    | 0.0           | 0.0           |
| Noncurrent portion of restricted marketable securities                                                                 | 0.0           | 0.0           |
| Income Approach Valuation Technique [Member]                                                                           |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Redeemable noncontrolling interests                                                                                    | 109.4         | 121.1         |
| Income Approach Valuation Technique [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Redeemable noncontrolling interests                                                                                    | 0.0           | 0.0           |
| Income Approach Valuation Technique [Member] | Significant Other Observable Inputs (Level 2) [Member]                  |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Redeemable noncontrolling interests                                                                                    | 0.0           | 0.0           |
| Income Approach Valuation Technique [Member] | Significant Unobservable Inputs (Level 3) [Member]                      |          |          |
| **Fair Value, Assets and Liabilities Measured on Recurring Basis [Abstract]**                                          |          |          |
| Redeemable noncontrolling interests                                                                                    | $ 109.4       | $ 121.1       |

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Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale which are intended to be held for less than one year or the normal operating cycle, whichever is longer and that are pledged to one or more secured parties who have the right to buy, sell, or re-pledge the collateral.
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Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale which are intended to be held for greater than one year or the normal operating cycle, whichever is longer and that are pledged to one or more secured parties who have the right to buy, sell, or re-pledge the collateral.
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| - Definition
The aggregate fair value as of the reporting date of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.
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