Retirement Benefit I (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension Benefits [Member]
Change in benefit obligation [Rollforward]
Benefit Obligation Beginning	$ 722.5	$ 647.0
Service cost	13.6	12.7	12.2
Interest cost	38.1	37.8	36.9
Defined Benefit Plan, Contributions by Plan Participants	0.7	0.7
Amendments	0	0
Actuarial loss (gain)	90.6	61.0
Currency impact	(0.5)	(1.3)
Defined Benefit Plan Other	(1.0)	(0.7)
Benefits paid change in obligation	(31.6)	(34.7)
Benefit Obligation Ending	832.4	722.5	647.0
Other Benefits [Member]
Change in benefit obligation [Rollforward]
Benefit Obligation Beginning	33.0	39.7
Service cost	0	0.3	0.6
Interest cost	1.6	2.1	1.7
Defined Benefit Plan, Contributions by Plan Participants	0	0
Amendments	0	(7.5)
Actuarial loss (gain)	1.8	2.1
Currency impact	0	0
Defined Benefit Plan Other	(0.3)	(0.5)
Benefits paid change in obligation	(2.4)	(3.2)
Benefit Obligation Ending	$ 33.7	$ 33.0	$ 39.7