Segment Information Net Sales Including Intersegment Sales (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ 2,608.1	$ 2,430.0
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	2,623.5	2,445.1
Operating Segments | Passive Safety
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	2,040.2	1,988.7
Operating Segments | Electronics
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	583.3	456.4
Corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	1.4	0.3
Intersegment Eliminations
Segment Reporting, Revenue Reconciling Item [Line Items]
Net sales	$ (16.8)	$ (15.4)