Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0.9	$ 0.7	$ 1.9	$ 1.4
Interest cost	1.2	1.1	2.4	2.2
Expected return on plan assets	(0.9)	(0.6)	(1.8)	(1.2)
Amortization of prior service costs	1.3	1.3	2.6	2.6
Amortization of actuarial loss	0.2	0	0.4	0
Periodic expense	2.7	2.5	5.5	5.0
Pension [Member] | Funded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan			2.7
Expected to contribute to pension plans	3.6		3.6
Pension [Member] | Unfunded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan			1.0
Expected to contribute to pension plans	0.3		0.3
Postretirement benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0	0	0
Interest cost	0.1	0.1	0.2	0.2
Expected return on plan assets	0	0	0	0
Amortization of prior service costs	0.1	0.1	0.2	0.2
Amortization of actuarial loss	0	0	0	0
Periodic expense	$ 0.2	$ 0.2	$ 0.4	$ 0.4