|**Segment Reporting - Table 4 (Details) - USD ($) $ in Millions**                                                                                                                                                                                                                                                                                                              | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                             | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                           
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|**Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                           
|Total assets for reportable segments                                                                                                                                                                                                                                                                                                                                           | $ 4,631.3                                                                                                                                                                                                                                                                                                                                                                  | [1]                                                                                                                                                                                                                                                                                                                                                                       
|Reclassification of noncurrent deferred income tax liabilities to net noncurrent deferred income tax assets                                                                                                                                                                                                                                                                    | (71.3)                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                           
|Total assets                                                                                                                                                                                                                                                                                                                                                                   | 4,631.3                                                                                                                                                                                                                                                                                                                                                                    | [1]                                                                                                                                                                                                                                                                                                                                                                       
|Operating Segments [Member]                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                           
|**Segment Reporting, Asset Reconciling Item [Line Items]**                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                           
|Total assets for reportable segments                                                                                                                                                                                                                                                                                                                                           | 4,702.6                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                                           
|Total assets                                                                                                                                                                                                                                                                                                                                                                   | $ 4,702.6                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                                           
|                                                                                                                                                                                                                                                                                                                                                                              
|[1]
Our consolidated assets as of September 30, 2016 include total assets of variable interest entities of $258.0 million, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of September 30, 2016 include total liabilities of the variable interest entities of $51.1 million. See Note 3, Variable Interest Entities. | [1]                                                                                                                                                                                                                                                                                                                                                                        | Our consolidated assets as of September 30, 2016 include total assets of variable interest entities of $258.0 million, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of September 30, 2016 include total liabilities of the variable interest entities of $51.1 million. See Note 3, Variable Interest Entities.
|[1]                                                                                                                                                                                                                                                                                                                                                                            | Our consolidated assets as of September 30, 2016 include total assets of variable interest entities of $258.0 million, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of September 30, 2016 include total liabilities of the variable interest entities of $51.1 million. See Note 3, Variable Interest Entities.

X- DefinitionSum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.
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