| **Redeemable Noncontrolling Interests (Tables)**    | 6 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 six months ended June 30, 2016 and 2015 (in millions): Six Months Ended June 30, 2016 2015Balance at beginning of period$121.1 $84.7Net income attributable to noncontrolling interests7.5 6.4Distributions declared(4.3) (4.0)Change in fair value(4.3) 11.4Balance at end of period$120.0 $98.5                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| 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 six months ended June 30, 2016 and 2015 (in millions): Three Months Ended June 30,  Six Months Ended June 30,  2016 2015 2016 2015Net income attributable to nonredeemable noncontrolling interests$15.0 $13.8 $29.8 $27.4Net income attributable to redeemable noncontrolling interests3.6 3.5 7.5 6.4Net income attributable to noncontrolling interests$18.6 $17.3 $37.3 $33.8 |

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Reconciliation of Noncontrolling Interests [Table Text Block]
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| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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No definition available.
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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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