Acquisitions Acquisitions (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended
	Feb. 28, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Acquisitions, net of cash acquired		$ 28.5	$ 284.5
Goodwill		$ 2,302.1		$ 2,258.3
Aquion
Business Acquisition [Line Items]
Acquisitions, net of cash acquired	$ 163.4
Goodwill	101.9
Business Acquisition, Goodwill, Expected Tax Deductible Amount	4.6
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	$ 121.1
Goodwill	118.0
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 7.6