Investment in Unconsolidated Affiliate and Related Party Transactions Summarized Balance Sheet Information of Equity Method Investment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Summarized Financial Information of Equity Method Investment [Line Items]
Current assets	$ 449.0	$ 416.0
Non-current assets	11,995.0	11,177.0
Current liabilities	1,615.0	1,279.0
Non-current liabilities	$ 3,211.0	$ 2,660.0

[Line Items] for Summarized Financial Information of Equity Method Investment [Table]

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