Acquisitions - Aggregate Disclosure Related to Business Acquisitions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Cash paid, net of cash acquired	$ 296.6	$ 57.7	$ 0.0
Contingent acquisition consideration	44.6	7.5
Excess purchase price allocated to goodwill	3,279.9	$ 2,956.1	$ 2,888.4
Aggregate total 2018
Business Acquisition [Line Items]
Total consideration	46.2
Cash paid, net of cash acquired	34.1
Contingent acquisition consideration	9.0
Allocation of purchase price to intangible assets, net	$ 41.6
Weighted average useful life of acquired intangible assets	9 years 4 months 18 days
Excess purchase price allocated to goodwill	$ 10.8
Aggregate total 2017
Business Acquisition [Line Items]
Total consideration	66.0
Cash paid, net of cash acquired	57.7
Contingent acquisition consideration	7.5
Allocation of purchase price to intangible assets, net	56.4
Weighted average useful life of acquired intangible assets		8 years 3 months 18 days
Excess purchase price allocated to goodwill	$ 12.8
Minimum
Business Acquisition [Line Items]
Discount rate	9.00%
Royalty rate	1.00%
Maximum
Business Acquisition [Line Items]
Discount rate	20.00%
Royalty rate	16.00%