Goodwill and Other Intangibles - Goodwill (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2017		Dec. 31, 2016	Dec. 31, 2015
Changes in the carrying amount of goodwill
Net goodwill balance, January 1		$ 1,702.2
Held for sale		7.3
Ending balance, December 31		$ 1,881.8		$ 1,702.2
Goodwill impairment test, weighted average cost of capital discount rate for future cash flow		10.40%
Sensitivity analysis Increase in discount rate		1.00%
Sensitivity analysis decrease in operating margin assumption		1.00%
Sensitivity analysis decrease in revenue growth rate		1.00%
Engine [Member]
Changes in the carrying amount of goodwill
Gross goodwill balance, January 1		$ 1,324.0		1,338.2
Accumulated impairment losses, January 1				(501.8)	$ (501.8)
Net goodwill balance, January 1		822.2		836.4
Acquisitions		0.0		0.0
Held for sale		(7.3)		0.0
Translation adjustment and other		42.9		(14.2)
Ending balance, December 31		857.8		822.2
Drivetrain [Member]
Changes in the carrying amount of goodwill
Gross goodwill balance, January 1		880.2		921.5
Accumulated impairment losses, January 1				(0.2)	$ (0.2)
Net goodwill balance, January 1		880.0		921.3
Acquisitions		125.8	[1]	(12.1)
Held for sale		0.0		0.0
Divestitures	[2]			(24.2)
Translation adjustment and other		18.2		(5.0)
Ending balance, December 31		$ 1,024.0		$ 880.0

[1] *Acquisitions during 2017 relate to the Company's 2017 purchase of Sevcon. Acquisitions during 2016 were related to the Company's fair value adjustments for the 2015 Remy acquisition, based on new information obtained during the measurement period.

[2] ** Divestitures relate to the Company's 2016 disposition of Remy light vehicle aftermarket business and Divgi-Warner Private Limited.