Equity Method Investments (Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Investments in subsidiaries	$ 0.0	$ 0.0
Other current liabilities	2,964.5	3,258.5
Other Liabilities, Noncurrent	1,235.7	1,358.6
Clean energy investments
Schedule of Equity Method Investments [Line Items]
Other liabilities	228.5	367.0
Other current liabilities	56.7	64.7
Other Liabilities, Noncurrent	171.8	302.3
Other assets | Clean energy investments
Schedule of Equity Method Investments [Line Items]
Investments in subsidiaries	226.0	320.6
Agila Specialties | Other assets
Schedule of Equity Method Investments [Line Items]
Investments in subsidiaries	$ 0.0	$ 75.8