Acquisitions and Discontinued Operations Acquisitions (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Acquisitions, net of cash acquired		$ 287.2	$ 0.9
Goodwill		$ 2,283.0		$ 2,072.7
Aquion
Business Acquisition [Line Items]
Acquisitions, net of cash acquired	$ 164.7
Goodwill	94.6
Indefinite-lived trade name intangible assets	15.7
Definite-lived customer relationships	$ 78.8
Estimated useful life	15 years
Pelican
Business Acquisition [Line Items]
Acquisitions, net of cash acquired	$ 122.5
Goodwill	$ 121.9