Reportable Business Segments, Segment Results (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) segment	Mar. 31, 2018 USD ($)
Segment reporting information
Number of reportable business segments | segment	2
Net sales	$ 1,958.5	$ 1,866.9
Segment operating income	376.2	376.9
Interconnect Products and Assemblies
Segment reporting information
Net sales	1,862.7	1,770.0
Cable Products and Solutions
Segment reporting information
Net sales	95.8	96.9
Operating Segment
Segment reporting information
Net sales	1,958.5	1,866.9
Segment operating income	420.5	402.4
Operating Segment | Interconnect Products and Assemblies
Segment reporting information
Net sales	1,862.7	1,770.0
Segment operating income	410.0	391.1
Operating Segment | Cable Products and Solutions
Segment reporting information
Net sales	95.8	96.9
Segment operating income	10.5	11.3
Inter-Segment
Segment reporting information
Net sales	18.6	11.5
Inter-Segment | Interconnect Products and Assemblies
Segment reporting information
Net sales	2.9	2.6
Inter-Segment | Cable Products and Solutions
Segment reporting information
Net sales	$ 15.7	$ 8.9