Retirement Benefit Plans (Components of net periodic benefit cost) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Retirement Plans [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.4	$ 1.1	$ 4.2	$ 3.6
Interest cost	4.4	5.4	13.2	15.9
Expected return on plan assets	(5.7)	(6.3)	(17.1)	(18.6)
Amortization of prior service cost/(credit)	0.0	0.0	0.0	0.1
Amortization of net actuarial gain/(loss)	0.4	0.7	1.4	2.0
Net periodic benefit cost	0.5	0.9	1.7	3.0
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	(0.3)
Amortization of prior service cost/(credit)	(2.8)	(2.9)	(7.7)	(7.6)
Amortization of net actuarial gain/(loss)	0.0	0.0	0.0	0.0
Net periodic benefit cost	$ (2.8)	$ (3.0)	$ (7.7)	$ (7.9)