Long-Term Debt (Convertible Notes) (Narrative) (Details) (North America [Member], USD $)	0 Months Ended			0 Months Ended				0 Months Ended	2 Months Ended	3 Months Ended
	Dec. 15, 2009 Subordinated Convertible Notes Due 2029 [Member]	Mar. 30, 2012 Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2011 Subordinated Convertible Notes Due 2029 [Member]	Dec. 15, 2009 1.00% Senior Convertible Notes Due 2012 [Member]	Mar. 30, 2012 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2011 1.00% Senior Convertible Notes Due 2012 [Member]	Sep. 30, 2007 1.00% Senior Convertible Notes Due 2012 [Member]	Nov. 30, 2006 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2006 0.875% Convertible Notes Due 2013 [Member]	Mar. 30, 2012 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2011 0.875% Convertible Notes Due 2013 [Member]
Debt Instrument [Line Items]
Debt principal amount	$ 429,500,000.0			$ 10,600,000.0			$ 475,000,000.0	$ 355,000,000
Nonconvertible debt borrowing rate on debt instrument issuance date	12.50%						7.50%	7.35%
Liability component of convertible notes	162,900,000	165,400,000	165,100,000	389,700,000	10,300,000	10,100,000	348,200,000	230,900,000		319,300,000	314,400,000
Debt discount	266,600,000	264,100,000	264,400,000	74,700,000	300,000	500,000	126,800,000	124,100,000		35,700,000	40,600,000
Debt issuance fees and expenses	14,500,000
Percentage of convertible notes tendered in exchange offer				97.80%
Amount of convertible notes tendered in exchange offer				464,400,000
Interest rate				1.00%	1.00%	1.00%		0.875%		0.875%	0.875%
Purchase price of Phelps Dodge International Corporation funded by proceeds from notes				707,600,000
Debt instrument original issuance date								Nov. 30, 2006
Conversion price per share								$ 50.36
Common stock covered under note hedges								7,048,880
Strike price of warrants, per share								$ 76.00		$ 76.00
Premium over the closing price of the companys shares of common stock included in strick price								92.40%
Payments of outstanding debt including accrued interest, under Company's amended credit facility									87,800,000
Payments for cost of note hedges									124,500,000
Payments of issuance costs and expenses of related to notes				12,300,000					9,400,000
Proceeds from issuance of warrants									80,400,000
Net increase in cash from receipt of the funds from convertible notes and related payments used for general corporate purposes including acquisitions									$ 213,700,000