| **Redeemable Noncontrolling Interests (Tables)**    | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
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| **Redeemable Noncontrolling Interest [Line Items]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |
| Redeemable Noncontrolling Interest                  | The following is a summary of the activity related to our Redeemable noncontrolling interests during the nine months ended September 30, 2014 and 2013 (in millions): Nine Months Ended September 30, 2014 2013Balance at beginning of period$13.5 $7.2Net income attributable to noncontrolling interests5.4 4.1Distributions declared(6.7) (3.6)Contribution to joint venture— 6.2Balance at end of period$12.2 $13.9                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
| Reconciliation of Noncontrolling Interests          | The following table reconciles the net income attributable to nonredeemable Noncontrolling interests, as recorded in the shareholders’ equity section of the condensed consolidated balance sheets, and the net income attributable to Redeemable noncontrolling interests, as recorded in the mezzanine section of the condensed consolidated balance sheets, to the Net income attributable to noncontrolling interests presented in the condensed consolidated statements of operations for the three and nine months ended September 30, 2014 and 2013 (in millions): Three Months Ended September 30, Nine Months Ended September 30,  2014 2013 2014 2013Net income attributable to nonredeemable noncontrolling interests$12.9 $12.6 $38.9 $38.4Net income attributable to redeemable noncontrolling interests1.8 1.5 5.4 4.1Net income attributable to noncontrolling interests$14.7 $14.1 $44.3 $42.5 |

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Reconciliation of Noncontrolling Interests [Table Text Block]
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| - Definition
Tabular disclosure of redeemable noncontrolling interest (as defined) included in the statement of financial position as either a liability or temporary equity. As of the date of the statement of financial position, such redeemable noncontrolling interest is currently redeemable, as defined, for cash or other assets of the entity at (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 entity.
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No definition available.
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