Fair Value Measurements and Risk (Details) In Millions, unless otherwise specified			9 Months Ended
	Sep. 30, 2011 USD ($) insurer country claim	Dec. 31, 2010 USD ($)	Sep. 30, 2011 Fixed-rate natural gas swaps USD ($) MMBtu	Sep. 30, 2011 Fixed-rate aluminum swaps USD ($)	Sep. 30, 2011 Currency forward contracts EUR (€)	Sep. 30, 2011 Recurring basis Total USD ($)	Dec. 31, 2010 Recurring basis Total USD ($)	Sep. 30, 2011 Recurring basis Significant Other Observable Inputs (Level 2) USD ($)	Dec. 31, 2010 Recurring basis Significant Other Observable Inputs (Level 2) USD ($)
Items measured at Fair Value on a Recurring Basis
Maximum period of cash flow hedging			12 months	12 months
Contract volume, or notional amount, of the commodity contracts (in MMBtu or Pounds)			2,700,000	2,900,000
Total contract value			$ 12.5	$ 3.4
Total notional amount related to the remaining outstanding currency forward contracts					246.7
Assets
Currency derivatives, assets						27.0	16.9	27.0	16.9
Commodity derivatives, assets							0.3		0.3
Total Assets, derivatives	27.0	17.2				27.0	17.2	27.0	17.2
Liabilities
Currency derivatives, liabilities						1.0	0.7	1.0	0.7
Commodity derivatives, liabilities						2.2	0.9	2.2	0.9
Total Liabilities, derivatives	$ 3.2	$ 1.6				$ 3.2	$ 1.6	$ 3.2	$ 1.6
Number of countries where company does business, greater than	40