Pensions and Postretirement Benefits Other than Pensions (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012 Update for plan amendment [Member] Other Postretirement Benefit Plans [Member]	Dec. 31, 2011 Prior to 2012 plan amendment [Member] Other Postretirement Benefit Plans [Member]
Company contributions	$ 8.2	$ 31.7
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate			3.75%	4.00%
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)			40.5
Actuarial loss due to plan amendment			21.3
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)			61.8
Postretirement Cost Projected			$ 39.7	$ 51.8