Financial Instruments (Summary Of Assets And Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt, including current portion	$ (1,089.3)	$ (835.2)
Foreign currency contract obligations	1.8	1.1
Natural gas contracts	(7.1)	(9.3)
Interest rate swap contracts	(24.2)	(14.0)
Quoted, Active Markets Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt, including current portion	(787.5)	(545.9)
Foreign currency contract obligations	1.8	1.1
Other Observable Inputs Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Total debt, including current portion	(301.8)	(289.3)
Natural gas contracts	(7.1)	(9.3)
Interest rate swap contracts	$ (24.2)	$ (14.0)