Restructuring Restructuring (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended					12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2014 labor_union	Dec. 31, 2013	Dec. 31, 2012	Feb. 28, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Agreements with Labor Unions, Number						2
Employee termination benefits								$ 9.0
Other restructuring charges								12.1
Asset Impairment Charges							24.8
Expected employee termination benefit costs to be incurred	9.0					9.0
Restructuring expense	17.8	9.6	13.0	38.4	35.8	90.8	39.8	27.4
Drivetrain [Member]
Restructuring Cost and Reserve [Line Items]
Employee termination benefits, number of employees effected						350
Employee termination benefits						50.6	7.5
Other restructuring charges						11.2	0.6
Restructuring expense						61.8	32.9
Gustav Wahler GmbH u. Co. KG and General Partner [Member]
Restructuring Cost and Reserve [Line Items]
Employee termination benefits, number of employees effected						95
Employee termination benefits						6.5
Corporate and Other [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expense	5.4	3.5	2.0	1.1	4.0	12.0	4.0
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	43.9				11.3	43.9	11.3	8.4
Restructuring expense						56.8	10.4
Payments for Restructuring						(18.6)	(8.1)
Restructuring Reserve, Translation Adjustment						(5.6)	0.6
Gustav Wahler GmbH u. Co. KG and General Partner [Member]
Restructuring Cost and Reserve [Line Items]
Business acquisition, percentage of voting interests acquired									100.00%
Engine [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	2.0				2.9	2.0	2.9	7.8
Restructuring expense						7.3	2.9
Payments for Restructuring						(7.9)	(8.1)
Restructuring Reserve, Translation Adjustment						(0.3)	0.3
Drivetrain [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Reserve	41.9				8.4	41.9	8.4	0.6
Restructuring expense						49.5	7.5
Payments for Restructuring						(10.7)	0
Restructuring Reserve, Translation Adjustment						$ (5.3)	$ 0.3