Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.1	$ 0.7	$ 3.0	$ 2.1
Interest cost	1.3	1.2	3.7	3.4
Expected return on plan assets	(0.9)	(0.7)	(2.7)	(1.9)
Amortization of prior service costs	1.3	1.4	3.9	4.0
Amortization of actuarial loss	0.6	0	1.0	0
Periodic expense	3.4	2.6	8.9	7.6
Pension [Member] | Funded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan			4.9
Expected to contribute to pension plans	0.7		0.7
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	0.1	0.1	0.1	0.1
Interest cost	0	0	0.2	0.2
Expected return on plan assets	0	0	0	0
Amortization of prior service costs	0.1	0.1	0.3	0.3
Amortization of actuarial loss	0	0	0	0
Periodic expense	$ 0.2	$ 0.2	$ 0.6	$ 0.6