Segment Information Capital Expenditures (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	$ 141.0	$ 129.5
Passive Safety
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	109.4	101.1
Electronics
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	30.9	27.3
Corporate and other
Segment Reporting, Other Significant Reconciling Item [Line Items]
Capital expenditures	$ 0.7	$ 1.1