Retirement Benefit Plans (Details) (Pension Plans, Defined Benefit [Member], USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Pension Plans, Defined Benefit [Member]
Components of net pension expense
Service cost	$ 7.4	$ 6.4	$ 21.5	$ 18.9
Interest cost	5.2	4.5	15.4	13.5
Expected return on plan assets	(8.1)	(6.5)	(23.9)	(19.4)
Amortization of prior service cost	(0.3)	(0.2)	(0.7)	(0.6)
Amortization of unrecognized actuarial loss	1.9	0.8	5.6	2.5
Net periodic benefit cost	$ 6.1	$ 5.0	$ 17.9	$ 14.9