Pension and Other Post-Retirement Plans - Funded Status (Details) (Defined benefit pension plans, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined benefit pension plans
Change in benefit obligation:
Benefit obligation at beginning of year	$ 113.3	$ 105.9
Service cost	2.2	2.5	2.1
Interest cost	4.9	4.7	4.7
Prior service cost	0	0
Participant contributions	1.0	1.2
Curtailments	0.2	0.2
Actuarial loss	15.5	3.5
Benefits paid	(2.7)	(2.8)
Settlement payments	0	0
Other, principally foreign exchange	(7.8)	(1.9)
Benefit obligation at end of year	126.6	113.3	105.9
Change in plan assets:
Fair value of plan assets at beginning of year	103.3	88.0
Business sale	0	0
Actual gain on plan assets	9.9	14.9
Employer contributions	2.1	3.3
Participant contributions	1.0	1.2
Benefits paid	(2.7)	(2.8)
Settlement payments	0	0
Other, principally foreign exchange	(7.2)	(1.3)
Fair value of assets at end of year	106.4	103.3	88.0
Amounts recognized in the consolidated balance sheets:
Funded status (current)	0	0
Funded status (non-current)	(20.2)	(10.0)
Accumulated other comprehensive income (pre-tax):
Unrecognized actuarial loss	23.3	12.6
Unrecognized prior service cost	(2.5)	(3.0)
Net amount recognized	$ 0.6	$ (0.4)