Investment in Unconsolidated Affiliates Summarized Balance Sheet Information of Equity Method Investment (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Summarized Balance Sheet Information of Equity Method Investment [Abstract]
Current assets	$ 402.0	$ 449.0
Non-current assets	12,045.0	11,995.0
Current liabilities	1,941.0	1,615.0
Non-current liabilities	$ 2,923.0	$ 3,211.0

Summarized Balance Sheet Information of Equity Method Investment [Abstract]

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The amount of current assets reported by an equity method investment of the entity.

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