Pension and Other Postretirement Plans (Net Periodic Benefit Cost) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 0.1	$ 0.1
Interest cost	7.8	8.5
Expected return on plan assets	(6.8)	(6.9)
Net periodic benefit cost (income)	1.1	1.7
Settlement loss	0.1	0
Net pension expense	1.2	1.7
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	0.1	0.1
Interest cost	0.3	0.4
Amortization of deferred gains, net	(0.5)	(0.8)
Net periodic benefit cost (income)	$ (0.1)	$ (0.3)