Segment Information Segment Assets (Detail) - USD ($) $ in Millions		Jun. 30, 2017	Dec. 31, 2016
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets		$ 8,443.7	$ 8,234.4
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets		7,763.9	7,352.5
Operating Segments | Passive Safety
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets		5,993.5	5,637.0
Operating Segments | Electronics
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets		1,770.4	1,715.5
Corporate and other
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	[1]	$ 679.8	$ 881.9

[1] Corporate and other assets mainly consist of cash and cash equivalents, income taxes and equity method investments.