Equity Method Investments (Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Investments in subsidiaries	$ 0.0	$ 0.0
Other current liabilities	2,147.6	2,964.5
Other Liabilities, Noncurrent	1,096.8	1,235.7
Clean energy investments
Schedule of Equity Method Investments [Line Items]
Other liabilities	145.4	228.5
Other current liabilities	45.1	56.7
Other Liabilities, Noncurrent	100.3	171.8
Other assets | Clean energy investments
Schedule of Equity Method Investments [Line Items]
Investments in subsidiaries	$ 138.7	$ 226.0