Pensions and Postretirement Benefits (Details 13) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net periodic postretirement benefit cost for other than pensions
Service cost	$ 1.1	$ 1.1	$ 1.4
Interest cost	15.6	17.4	19.6
Weighted average assumptions used to determine net periodic benefit cost
Discount rate	5.29%	5.55%	6.38%
Initial health care rate of increase	7.50%	7.50%	7.80%
Ultimate health care rate of increase	5.00%	5.00%	5.00%
Year ultimate trend reached	2018	2017	2015
Other Postretirement Benefit Plans Defined Benefit [Member]
Net periodic postretirement benefit cost for other than pensions
Service cost	1.1	1.1	1.4
Interest cost	15.7	17.4	19.6
Amortization of prior service cost	(0.4)	(0.1)	(0.2)
Net periodic benefit cost	$ 16.3	$ 18.4	$ 20.8
Weighted average assumptions used to determine net periodic benefit cost
Initial health care rate of increase	7.50%	7.30%	7.80%