Retirement Benefit Plans - Benefit Obligation and Plan Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Change in plan assets:
Funded status of plan	$ (156.8)		$ (139.3)
Amounts recognized in Balance Sheet [Abstract]
Non-current liabilities	(326.6)		(312.9)
NSK Warner [Member]
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net amount	5.6	[1]	4.9	[1]
U.S. Plans:
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	293.6		330.1
Interest cost	12.1		11.6		14.3
Actuarial (gain) loss	34.0		(18.7)
Benefits paid	(33.5)		(29.4)
Projected benefit obligation, December 31	306.2		293.6		330.1
Change in plan assets:
Fair value of plan assets, January 1	274.1		282.7
Actual return on plan assets	25.0		20.8
Fair value of plan assets, December 31	265.6		274.1		282.7
Funded status of plan	(40.6)		(19.5)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	0		0
Current liabilities	(0.1)		(0.1)
Non-current liabilities	(40.5)		(19.4)
Net amount	(40.6)		(19.5)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	151.6		115.0
Net prior service cost (credit)	(9.0)		9.7
Net amount	142.6	[1]	124.7	[1]
Defined Benefit Plan, Accumulated Benefit Obligation	306.2		293.6
Non-U.S. Plans:
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	482.7		447.6
Service cost	12.8		12.4		9.1
Interest cost	18.1		16.6		17.2
Plan participants’ contributions	0.4		0.4
Plan amendments			0.6
Actuarial (gain) loss	82.0		11.8
Currency translation	(53.5)		10.6
Other	3.2		(2.7)
Benefits paid	(17.9)		(14.6)
Projected benefit obligation, December 31	527.8		482.7		447.6
Change in plan assets:
Fair value of plan assets, January 1	345.0		177.9
Actual return on plan assets	52.0		23.6
Employer contribution	53.4		150.4
Currency translation	(37.0)		7.7
Other	(0.3)		(0.4)
Fair value of plan assets, December 31	395.6		345.0		177.9
Funded status of plan	(132.2)		(137.7)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	4.1		0
Current liabilities	(2.6)		(2.6)
Non-current liabilities	(133.7)		(135.1)
Net amount	(132.2)		(137.7)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	160.4		130.6
Net prior service cost (credit)	0.9		1.1
Net amount	161.3	[1]	131.7	[1]
Defined Benefit Plan, Accumulated Benefit Obligation	507.7		464.8
U.S. other postretirement benefit plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	177.5		220.5
Service cost	0.3		0.4		0.5
Interest cost	6.7		6.8		10.1
Actuarial (gain) loss	15.0		(29.7)
Benefits paid	(29.8)		(20.5)
Projected benefit obligation, December 31	169.7		177.5		220.5
Change in plan assets:
Funded status of plan	(169.7)		(177.5)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	0		0
Current liabilities	(17.3)		(19.1)
Non-current liabilities	(152.4)		(158.4)
Net amount	(169.7)		(177.5)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	56.4		44.0
Net prior service cost (credit)	(29.7)		(36.1)
Net amount	$ 26.7	[1]	$ 7.9	[1]

[1] AOCI shown above does not include our equity investee, NSK-Warner. NSK-Warner had an AOCI loss of $5.6 million and $4.9 million at December 31, 2014 and 2013, respectively.