Employee Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Pension [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 1.0	$ 1.0
Interest cost	1.2	1.2
Expected return on plan assets	(1.0)	(0.9)
Amortization of prior service costs	1.2	1.3
Amortization of actuarial loss	0.6	0.2
Periodic expense	3.0	2.8
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	5.4
Pension [Member] | Unfunded Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Contributions to pension plan	0.6
Expected to contribute to pension plans	2.7
Pension [Member] | Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expected to contribute to pension plans	0.2
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	0	0
Interest cost	0.1	0.1
Amortization of prior service costs	0.1	0.1
Amortization of actuarial loss	0	0
Periodic expense	$ 0.2	$ 0.2