Goodwill and Other Intangibles - Goodwill (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Changes in the carrying amount of goodwill
Net goodwill balance, January 1	$ 1,881.8
Ending balance, December 31	$ 1,853.4		$ 1,881.8
Goodwill impairment test, weighted average cost of capital discount rate for future cash flow	10.90%
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	$ 1,359.6		1,324.0
Accumulated impairment losses, January 1			(501.8)	$ (501.8)
Net goodwill balance, January 1	857.8		822.2
Acquisitions	0.0		0.0
Held for sale	0.0		(7.3)
Translation adjustment and other	(16.5)		42.9
Ending balance, December 31	841.3		857.8
Drivetrain [Member]
Changes in the carrying amount of goodwill
Gross goodwill balance, January 1	1,024.2		880.2
Accumulated impairment losses, January 1			(0.2)	$ (0.2)
Net goodwill balance, January 1	1,024.0		880.0
Acquisitions	1.7	[1]	125.8
Held for sale	0.0		0.0
Translation adjustment and other	(13.6)		18.2
Ending balance, December 31	$ 1,012.1		$ 1,024.0

[1] *Acquisitions relate to the Company's 2017 purchase of Sevcon.