Revenue from Continuing Operations Disaggregated by Primary Region and Products (Detail) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation Of Revenue [Line Items]
Net sales		$ 2,033.0	$ 1,952.6	$ 6,485.4	$ 5,978.1
Airbag Products and Other
Disaggregation Of Revenue [Line Items]
Net sales	[1]	1,357.4	1,276.5	4,234.9	3,947.6
Seatbelt Products
Disaggregation Of Revenue [Line Items]
Net sales	[1]	675.6	676.1	2,250.5	2,030.5
China
Disaggregation Of Revenue [Line Items]
Net sales		351.9	343.2	1,103.5	973.1
Japan
Disaggregation Of Revenue [Line Items]
Net sales		196.3	193.4	606.4	578.6
Rest of Asia
Disaggregation Of Revenue [Line Items]
Net sales		200.9	200.4	623.6	587.9
Americas
Disaggregation Of Revenue [Line Items]
Net sales		684.8	575.3	2,034.3	1,835.9
Europe
Disaggregation Of Revenue [Line Items]
Net sales		$ 599.1	$ 640.3	$ 2,117.6	$ 2,002.6

[1] Including Corporate and other sales.