Long-Term Debt (Narrative) (Details) (USD $)	12 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended			12 Months Ended				12 Months Ended				12 Months Ended	0 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended							0 Months Ended																				0 Months Ended
	Dec. 31, 2011	Jul. 22, 2011	Jul. 22, 2011 Revolving Credit Facility [Member]	Sep. 30, 2011 Revolving Credit Facility [Member]	Jul. 22, 2011 Asset-Based Revolving Credit Facility [Member]	Dec. 31, 2011 Asset-Based Revolving Credit Facility [Member]	Jul. 22, 2011 Asset-Based Revolving Credit Facility [Member] Maximum [Member]	Jul. 22, 2011 Asset-Based Revolving Credit Facility [Member] Minimum [Member]	Dec. 15, 2009 Subordinated Convertible Notes [Member]	Dec. 31, 2011 9.5% Senior Notes [Member]	Dec. 31, 2011 Senior Floating Rate Notes [Member]	Dec. 31, 2010 Senior Floating Rate Notes [Member]	Dec. 31, 2011 Senior Floating Rate Notes Due 2015 [Member]	Dec. 31, 2011 Subordinated Convertible Notes Due 2029 [Member]		Dec. 31, 2010 Subordinated Convertible Notes Due 2029 [Member]	Dec. 15, 2009 Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2011 Senior Unsecured Notes [Member]	Nov. 30, 2006 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2011 0.875% Convertible Notes Due 2013 [Member]		Jul. 22, 2011 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2010 0.875% Convertible Notes Due 2013 [Member]	Dec. 15, 2009 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2011 1.00% Senior Convertible Notes Due 2012 [Member]		Dec. 31, 2010 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2008 1.00% Senior Convertible Notes Due 2012 [Member]	Sep. 30, 2007 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2011 7.125% Senior Notes Due 2017 [Member]	Dec. 31, 2010 7.125% Senior Notes Due 2017 [Member]	Jul. 22, 2011 CANADA [Member] Asset-Based Revolving Credit Facility [Member]	Dec. 31, 2011 Parent Company [Member] Senior Floating Rate Notes [Member]	Dec. 31, 2010 Parent Company [Member] Senior Floating Rate Notes [Member]	Dec. 31, 2010 Parent Company [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2010 Parent Company [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2010 Parent Company [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2010 Parent Company [Member] 7.125% Senior Notes Due 2017 [Member]	Dec. 15, 2009 Parent Company [Member] North America [Member] Subordinated Convertible Notes [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] Senior Floating Rate Notes [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] Senior Floating Rate Notes Due 2015 [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2010 Parent Company [Member] North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 15, 2009 Parent Company [Member] North America [Member] Subordinated Convertible Notes Due 2029 [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2010 Parent Company [Member] North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Nov. 30, 2006 Parent Company [Member] North America [Member] 0.875% Convertible Notes Due 2013 [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2010 Parent Company [Member] North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 15, 2009 Parent Company [Member] North America [Member] 1.00% Senior Convertible Notes Due 2012 [Member]	Dec. 31, 2011 Parent Company [Member] North America [Member] 7.125% Senior Notes Due 2017 [Member]	Jul. 22, 2011 Potential Increase [Member] Asset-Based Revolving Credit Facility [Member]
Maturities of long-term debt range, start	Dec. 31, 2012
Maturities of long-term debt range, end	Dec. 31, 2016
Maturities of long-term debt in 2012	$ 156,300,000
Maturities of long-term debt in 2013	343,600,000
Maturities of long-term debt in 2014	9,800,000
Maturities of long-term debt in 2015	163,100,000
Maturities of long-term debt in 2016	1,400,000
Maturities of long-term debt in 2017 and thereafter	374,700,000
Principal amount of Subordinated Convertible Notes for each $1000 of Senior Convertible Notes																	925
Principal amount of Senior Convertible Notes for each $925 of Subordinated Convertible Notes																								1,000
Conversion price per share														$ 36.75	[1]					$ 50.36	[1]				$ 83.93	[1]
Converted instrument, warrants or options issued	7,048,880
Debt principal amount													125,000,000					325,000,000				355,000,000							475,000,000	200,000,000	200,000,000		125,000,000	125,000,000	429,500,000	355,000,000	10,600,000	200,000,000	429,500,000		125,000,000	429,500,000	429,500,000	429,500,000	355,000,000	355,000,000	355,000,000	10,600,000	10,600,000	10,600,000	200,000,000
Debt maturity date																																								2015	2015	2029			2013			2012			2017
Line of credit facility, expiration period						90 days
Interest rate on notes										9.50%	3.00%	2.70%								0.875%				1.00%	1.00%					7.125%	7.125%																				7.125%
Fair value of debt											117,500,000	114,400,000		412,300,000		521,000,000				329,700,000			350,600,000		9,800,000		9,700,000			198,500,000	197,500,000
Nonconvertible debt borrowing rate on debt instrument issuance date									12.50%										7.35%	0.875%					1.00%			7.50%		7.125%
Liability component of convertible notes									162,900,000					165,100,000		163,900,000			230,900,000	314,400,000			295,500,000	389,700,000	10,100,000		9,500,000		348,200,000
Equity component of convertible notes									266,600,000										124,100,000					74,700,000					126,800,000
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
Debt instrument original issuance date																			Nov. 30, 2006						Sep. 30, 2007
Purchase price of Phelps Dodge International Corporation funded by proceeds from notes																									707,600,000
Common stock covered under note hedge														11,686,075	[1]					7,048,880	[1]				5,659,245	[1]
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
Payment of issuance costs and expenses of related to notes																		7,900,000		9,400,000					12,300,000
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
Notes originally issued amount																		325,000,000
Payments for senior notes										285,000,000
Payment for accrued interest related to senior notes										9,300,000
Payment for tender fees and the inducement premium related to senior notes										20,500,000
Net cash proceeds from notes used for general corporate purposes																		2,300,000
Borrowing capacity under credit facility		400,000,000	400,000,000		400,000,000
Credit facility term period, years					5 years
Portion of credit facility designated for foreign currency tranche																																40,000,000
Revolving credit facility, increase in additional borrowings																																																				100,000,000
Line of credit facility, expiration date			Jul. 31, 2012
Deferred financing costs capitalized						4,800,000
Unamortized fees and expenses				1,300,000
Threshold for line of credit facility borrowings								40,000,000
Threshold for line of credit facility Percentage Of Asset Based Revolving Credit Facililties					10.00%
Equity interest pledged in foreign subsidiaries, percentage					65.00%
Line of credit facility commitment fee, percentage							0.50%	0.375%
Non-cash loss on debt extinguishment																								7,600,000
Non-cash loss on debt extinguishment, per share																								$ 0.10
Write-off of unamortized debt																								$ 4,900,000

[1] In the event of a “fundamental change” or exceeding the aforementioned average pricing thresholds, the Company would be required to classify the amount outstanding as a current liability.