Financial Instruments and Risk Management (Details) In Millions, except Share data, unless otherwise specified			9 Months Ended		9 Months Ended			9 Months Ended
	Oct. 02, 2011 USD ($) method Ratio	Dec. 31, 2010 USD ($)	Oct. 02, 2011 Commodity contracts USD ($)	Dec. 31, 2010 Commodity contracts USD ($)	Oct. 02, 2011 Interest rate swap agreements USD ($)	Oct. 02, 2011 Inflation option contracts USD ($)	Oct. 02, 2011 Inflation option contracts EUR (€)	Oct. 02, 2011 Foreign exchange forward contracts and option collar contracts USD ($)	Oct. 02, 2011 Equity contracts USD ($)	Oct. 02, 2011 Total return swaps outstanding until March 2012 swap	Oct. 02, 2011 Total return swaps outstanding until September 2012
Financial Instruments and Risk Management
Number of methods through which entity manages commodity price risk in connection with market price fluctuations of aluminum ingot	2
Financial Instruments and Risk Management
Notional amount of derivatives			$ 700	$ 1,000	$ 303	$ 154	€ 115	$ 434
Period within which derivative will expire			four years		four years	two years	two years	two years
Loss on derivatives included in accumulated other comprehensive earnings (loss), net of tax			9.1		0.3			0.9
Net loss expected to be recognized in the consolidated statement of earnings during the next 12 months			9.9		0.3			0.9
Change in company's stock price (in dollars per share)									$ 1
Impact of change in the company's stock price on pretax earnings									1.8
Notional value of the swap (in shares)										1,000,000	500,000
Number of swaps										1
Fair value of the swap at loss									0.5
Aggregate fair value derivative instruments with credit-risk-related contingent features that were in a net liability position	$ 58.2	$ 26.3