Business Acquisitions - Summary of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Dec. 31, 2018	Feb. 02, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 1,784.4		$ 1,089.0	$ 991.0
Aclara
Business Acquisition [Line Items]
Accounts receivable		$ 118.1
Inventories		73.5
Other current assets		8.5
Property, plant and equipment		30.9
Intangible assets		434.0
Accounts payable		(51.8)
Other accrued liabilities		(93.3)
Deferred tax liabilities, net		(42.1)
Other non-current liabilities		(67.7)
Noncontrolling interest		(2.5)
Goodwill		708.7
Total Estimate of Consideration Transferred, Net of Cash Acquired		$ 1,116.3