Employee Retirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Pension Benefits
Other disclosures
Contributions	$ 14.5	$ 16.6	$ 46.7	$ 73.7
Pension Benefits - U.S.
Components of Net Periodic Benefit Cost
Service cost	5.2	6.6	18.5	19.7
Interest cost	7.3	6.6	21.2	20.6
Expected return on plan assets	(8.3)	(7.7)	(23.6)	(22.9)
Net amortization	(2.9)	(1.1)	(8.9)	(5.4)
Settlement loss	0	1.5	0	2.2
Curtailment gain	0	0	0	0
Net pension/postretirement expense	7.1	8.1	25.0	25.0
Pension Benefits - Non-U.S.
Components of Net Periodic Benefit Cost
Service cost	0.3	(0.5)	0.9	3.0
Interest cost	2.2	2.9	6.8	8.5
Expected return on plan assets	(3.0)	(3.5)	(9.0)	(9.7)
Net amortization	0	(0.1)	0.1	0.5
Settlement loss	0	0	0	0
Curtailment gain	0	0	0	(13.1)
Net pension/postretirement expense	(0.5)	(1.0)	(1.4)	(11.8)
Pension Benefits - U.K.
Other disclosures
Contributions	0	0.5	3.2	13.7
Employer's matching contribution as percentage of employee contributions			100.00%
Unamortized prior service cost					13.1
Pension Benefits - U.K. | Maximum
Other disclosures
Percentage of employee contributions eligible for employer match			8.00%
Postretirement Benefits (U.S.)
Components of Net Periodic Benefit Cost
Service cost	0	0.1	0.2	0.2
Interest cost	0.2	0.2	0.6	0.7
Expected return on plan assets	0	0	0	0
Net amortization	0	0.1	0	0
Settlement loss	0	0	0	0
Curtailment gain	0	0	0	0
Net pension/postretirement expense	$ 0.2	$ 0.2	$ 0.8	$ 0.9
Key officer postretirement car benefit plan
Other disclosures
Period for which assigned car benefit is available			15 years
Eligible age for car benefit			80 years
Key officer postretirement car benefit plan | Minimum
Other disclosures
Service period					20 years
Retirement age					58 years