Restructuring and Acquisition-Related Costs - Restructuring Reserve Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 39.8	$ 44.2	$ 17.4
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	19.4	2.5	2.0
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	20.4	11.7	13.9
2019 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	18.0
Asset Impairment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	0.0	$ 30.0	$ 1.5
Minimum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining	20.0
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and related cost, expected cost remaining	30.0
Driveline [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	6.4
Metal Forming [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	21.5
Casting [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 0.7