Affiliated Equity - Additional Information (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Affiliate Equity [Line Items]
Distributions paid to affiliate partners	$ 293.6	$ 266.8
Payments to acquire interest in affiliates	104.3	121.3
Issuance of interest in affiliates	6.3	$ 8.8
Other Assets
Affiliate Equity [Line Items]
Due from affiliates	17.8		$ 12.4
Other Liabilities
Affiliate Equity [Line Items]
Due to affiliates	$ 28.7		$ 49.2

[Line Items] for Affiliate Equity [Table]

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For an unclassified balance sheet, amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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Amount of payable due to an entity that is affiliated with the reporting entity by means of direct or indirect ownership.

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