Income Taxes (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended			1 Months Ended	3 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Jul. 31, 2012 Cerro Verde [Member]	Sep. 30, 2012 Cerro Verde [Member]	Sep. 30, 2011 Cerro Verde [Member]
Income Tax Disclosure [Line Items]
Taxes on U.S. operations	$ 98		$ 163	$ 291		$ 421
Taxes on international operations	117	[1]	645	837	[1]	2,277
Total	215		808	1,128		2,698
Consolidated effective income tax rate (percent)				27.00%		36.00%
Effective Income Tax Rate, Excluding Deferred Foreign Income Tax Expense (Benefit) Associated with Foreign Reinvested Profits				33.00%
Term of Stability Agreement							15 years
Effective Date of Stability Agreement with Foreign Government							Jan. 01, 2014
Foreign Income Tax Rate							30.00%
Foreign Income Tax Rate Under New Stability Agreegment							32.00%
Deferred Foreign Income Tax Expense from New Stability Agreement								26
Deferred Foreign Income Tax Expense from New Stability Agreement Net of Noncontrolling Interest								23
Deferred Foreign Income Tax Expense (Benefit) Associated with Foreign Reinvested Profits								(234)
Deferred Foreign Income Tax Expense (Benefit) Associated with Foreign Reinvested Profits, Net of Noncontrolling Interest								(123)
Additional Tax Expense From New Legislation On Mining Royalties									57
Additional Tax Expense From New Legislation On Mining Royalties Net Of Noncontrolling Interests									$ 50

[1] Included a net tax benefit of $234 million associated with an adjustment to Cerro Verde's deferred income tax liability.