Components of Net Periodic Benefit Cost (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Components of Net Periodic Benefit Cost
Defined contribution benefits plans	$ 5.1	$ 4.3	$ 10.5	$ 9.3
Pension Plan, Defined Benefit [Member]
Components of Net Periodic Benefit Cost
Service cost - benefits earned during the period	2.0	3.6	3.9	7.1
Interest cost on projected benefit obligation	8.4	8.1	17.0	16.2
Expected return on plan assets	(12.0)	(12.0)	(24.0)	(24.0)
Settlement loss	0	0	0.4	0
Curtailment loss	0	0	0.9	0
Amortization of unrecognized transition obligation	0	0	0.1	0.1
Amortization of prior service cost	0.3	0.2	0.7	0.6
Recognized actuarial net (gain) or loss	3.0	6.4	5.8	13.0
Net periodic benefit (income) cost	1.7	6.3	4.8	13.0
Other Postretirement Benefit Plan, Defined Benefit [Member]
Components of Net Periodic Benefit Cost
Curtailment loss			$ (3.0)