Long-Term Debt (Convertible Notes) (Details) (USD $)	12 Months Ended				0 Months Ended	12 Months Ended		0 Months Ended								12 Months Ended	0 Months Ended	2 Months Ended
	Dec. 31, 2012	Dec. 31, 2012 Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2012 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 15, 2009 1.00% Senior Convertible Notes Due 2012 [Member]	Nov. 30, 2006 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2012 0.875% Convertible Notes Due 2013 [Member]	Jul. 22, 2011 0.875% Convertible Notes Due 2013 [Member]	Dec. 15, 2009 North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2012 North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2011 North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2012 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2011 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 15, 2009 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2008 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Sep. 30, 2007 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2012 North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member] Phelps Dodge International Corporation [Member]	Nov. 30, 2006 North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2006 North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2012 North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2011 North America [Member] 0.875% Convertible Notes Due 2013 [Member]
Debt Instrument [Line Items]
Debt principal amount							$ 355,000,000	$ 429,500,000					$ 10,600,000		$ 475,000,000		$ 355,000,000
Nonconvertible debt borrowing rate on debt instrument issuance date						0.875%		12.50%						7.50%			7.35%
Liability component of convertible notes								162,900,000	429,500,000	429,500,000	0	10,600,000	389,700,000		348,200,000		230,900,000		355,000,000	355,000,000
Unamortized discount								266,600,000	263,000,000	264,400,000	0	500,000	74,700,000		126,800,000		124,100,000		20,400,000	40,600,000
Debt issuance fees and expenses								14,500,000
Percentage of convertible notes tendered in exchange offer				97.80%							97.80%
Amount of convertible notes tendered in exchange offer				464,400,000							464,400,000
Interest rate			1.00%	1.00%		0.875%					1.00%	1.00%	1.00%				0.875%		0.875%	0.875%
Debt instrument original issuance date			Sep. 30, 2007		Nov. 30, 2006
Cost of acquired entity																707,600,000
Payment of issuance costs and expenses of related to notes																12,300,000		9,400,000
Conversion price per share		$ 36.75	$ 83.93			$ 50.36											$ 50.36
Common stock covered under note hedges		11,686,075	5,659,245			7,048,880											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%
Payment of outstanding debt including accrued interest, under the Company's amended credit facility																		87,800,000
Payments for cost of note hedges																		124,500,000
Proceeds from the issuance of the warrants																		80,400,000
Net increase in cash from receipt of the funds from convertible notes and related payments used for general																		$ 213,700,000