Business Combinations - Summary of Aggregate Final Estimated Fair Values of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 10,668.4	$ 10,643.9	$ 9,934.2
Cayenne Medical, CTC, CDD and MedTech [Member]
Business Acquisition [Line Items]
Current assets		66.4
Property, plant and equipment		4.5
Intangible assets		172.9
Goodwill		337.1
Other assets		38.2
Total assets acquired		619.1
Current liabilities		20.0
Long-term liabilities		99.4
Total liabilities assumed		119.4
Net assets acquired		$ 499.7