Fair Value of Financial Instruments (Schedule of Summarized Financial Information of Equity Investees) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Summarized Financial Information of Equity Investees
Current assets	$ 89.5	$ 71.1
Long-term assets	1,126.5	234.7
Total assets	1,216.0	305.8
Current liabilities	153.6	119.5
Long-term liabilities	986.0	199.6
Total liabilities	1,139.6	319.1
Net losses	$ 0.2	$ 13.3