Retirement Benefit Plans - Plan Assets and Funded Status (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Amounts recognized in Balance Sheet [Abstract]
Non-current liabilities	$ 457.0		$ 438.1
Plans with benefit obligations in excess of plan assets [Abstract]
Pension plans with accumulated benefit obligations in excess of plan assets, aggregate accumulated benefit obligation	656.9		634.9
Pension plans with accumulated benefit obligations in excess of plan assets, aggregate fair value of plan assets	435.5		432.2
Plans with benefit obligations in excess of plan assets, deficiency	(221.4)		(202.7)
United States Pension Deficiency [Member]
Plans with benefit obligations in excess of plan assets [Abstract]
Plans with benefit obligations in excess of plan assets, deficiency	(47.0)		(39.0)
United Kingdom Pension Deficiency [Member]
Plans with benefit obligations in excess of plan assets [Abstract]
Plans with benefit obligations in excess of plan assets, deficiency	(13.4)		(7.5)
Germany Pension Deficiency [Member]
Plans with benefit obligations in excess of plan assets [Abstract]
Plans with benefit obligations in excess of plan assets, deficiency	(128.7)		(128.0)
Other Countries Pension Deficiency [Member]
Plans with benefit obligations in excess of plan assets [Abstract]
Plans with benefit obligations in excess of plan assets, deficiency	(32.3)		(28.2)
NSK Warner [Member]
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Accumulated benefit obligation	6.9		6.1
U.S. pension plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	326.2		316.5
Service cost	0		0		0.3
Interest cost	16.1		17.5		20.7
Plan participants' contributions	0		0
Plan amendments	0		0
Actuarial (gain) loss	21.8		19.2
Currency translation	0		0
Other	0		1.1
Benefits paid	(26.7)		(28.1)
Projected benefit obligation, December 31	337.4		326.2		316.5
Change in plan assets:
Fair value of plan assets, January 1	287.2		269.1
Actual return on plan assets	8.9		35.6
Employer contribution	21.0		10.6
Currency translation	0		0
Defined benefit plan, other changes in plan assets	0		0
Fair value of plan assets, December 31	290.4		287.2		269.1
Funded status of plan	(47.0)		(39.0)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	0		0
Current liabilities	0.1		0.1
Non-current liabilities	46.9		38.9
Net amount recognized	(47.0)		(39.0)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	(172.8)		(145.7)
Net prior service cost (credit)	(11.3)		(12.1)
Net amount recognized	161.5	[1]	133.6	[1]
Accumulated benefit obligation	337.4		326.2
Non-U.S. pension plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	326.0		326.5
Service cost	9.1		7.4		9.9
Interest cost	17.8		17.6		16.5
Plan participants' contributions	0.3		0.5
Plan amendments	(0.5)		1.2
Actuarial (gain) loss	11.9		(0.4)
Currency translation	(5.8)		(12.2)
Other	0.9		0.1
Benefits paid	(15.4)		(14.7)
Projected benefit obligation, December 31	344.3		326.0		326.5
Change in plan assets:
Fair value of plan assets, January 1	154.6		144.0
Actual return on plan assets	5.0		14.2
Employer contribution	16.0		14.5
Currency translation	(0.7)		(3.9)
Defined benefit plan, other changes in plan assets	(4.9)		0
Fair value of plan assets, December 31	154.9		154.6		144.0
Funded status of plan	(189.4)		(171.4)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	0.5		0.5
Current liabilities	6.5		8.1
Non-current liabilities	183.4		163.8
Net amount recognized	(189.4)		(171.4)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	(54.4)		(37.4)
Net prior service cost (credit)	0.8		1.4
Net amount recognized	55.2	[1]	38.8	[1]
Accumulated benefit obligation	327.9		316.8
U.S. other postemployment benefit plans [Member]
Change in benefit obligation [Roll Forward]
Projected benefit obligation, January 1	261.9		278.5
Service cost	0.7		0.8		0.8
Interest cost	11.8		14.5		18.6
Plan participants' contributions	0		0
Plan amendments	3.9		0
Actuarial (gain) loss	(6.8)		(7.2)
Currency translation	0		0
Other	0		0
Benefits paid	(20.5)		(24.7)
Projected benefit obligation, December 31	251.0		261.9		278.5
Change in plan assets:
Fair value of plan assets, January 1
Fair value of plan assets, December 31
Funded status of plan	(251.0)		(261.9)
Amounts recognized in Balance Sheet [Abstract]
Non-current assets	0		0
Current liabilities	24.3		26.5
Non-current liabilities	226.7		235.4
Net amount recognized	(251.0)		(261.9)
Amounts recognized in accumulated other comprehensive Income Loss) [Abstract]
Net actuarial loss	(106.3)		(120.0)
Net prior service cost (credit)	(48.7)		(59.5)
Net amount recognized	$ 57.6	[1]	$ 60.5	[1]

[1] AOCI shown above does not include our equity investee, NSK-Warner. NSK-Warner had an AOCI loss of $6.9 million and $6.1 million at December 31, 2011 and 2010, respectively.