Acquisitions and Divestitures (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended				3 Months Ended		9 Months Ended		0 Months Ended	9 Months Ended	12 Months Ended
	Sep. 28, 2012	Sep. 30, 2011		Sep. 28, 2012	Sep. 30, 2011		Sep. 28, 2012 CHINA [Member] Alcan Cable [Member]	Sep. 28, 2012 North America [Member]	Sep. 30, 2011 North America [Member]	Sep. 28, 2012 North America [Member]	Sep. 30, 2011 North America [Member]	Sep. 04, 2012 North America [Member] Alcan Cable [Member]	Sep. 28, 2012 North America [Member] Alcan Cable [Member]	Dec. 31, 2011 North America [Member] Alcan Cable [Member]	Sep. 28, 2012 North America [Member] Alcan Cable [Member] Minimum [Member] employees
Business Acquisition [Line Items]
Cost of acquired entity, purchase price												$ 151.0
Customary adjustment, primarily related to working capital												20.3
Anticipated acquisition before the end of 2012							34.0
Cash paid for acquired entity												171.3
Selling, general and administrative expenses	93.5	93.0	[1]	291.7	281.7	[1]						3.2
Number of employees															750
Net sales	1,500.6	1,517.8	[1]	4,411.2	4,497.6	[1]		563.6	528.6	1,652.8	1,636.8		47.6	610.0
Operating income	$ 69.5	$ 58.7	[1]	$ 189.3	$ 203.3	[1]		$ 26.8	$ 27.7	$ 93.8	$ 104.5		$ 0.1

[1] See Note 23 - Restatement of Condensed Consolidated Financial Statements (Unaudited)