Retirement Benefit Plans (Components of net periodic benefit cost) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Retirement Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.4	$ 1.3	$ 2.8	$ 2.5
Interest cost	4.4	5.2	8.8	10.5
Expected return on plan assets	(5.7)	(6.1)	(11.4)	(12.3)
Amortization of prior service cost/(credit)	0.0	0.1	0.0	0.1
Amortization of net actuarial gain/(loss)	0.5	0.7	1.0	1.3
Net periodic benefit cost	0.6	1.2	1.2	2.1
Medical Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0.0	0.0	0.0	0.0
Interest cost	0.0	0.0	0.0	0.0
Expected return on plan assets	0.0	(0.1)	0.0	(0.2)
Amortization of prior service cost/(credit)	(2.9)	(2.5)	(4.9)	(4.7)
Amortization of net actuarial gain/(loss)	0.0	0.0	0.0	0.0
Net periodic benefit cost	$ (2.9)	$ (2.6)	$ (4.9)	$ (4.9)