Fair Value Measurement (Unaudited) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Investment securities (current and long-term):
Escrow Deposit	$ 115
Derivatives:
Derivative assets	307		330
Liabilities
Derivative Liability	51		99
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities (current and long-term):
Investment securities	25	[1],[2],[3]	23	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	10	[2],[3],[4]	11	[2],[3],[4]
Derivatives:
Derivative assets	6	[2],[5]	0	[2],[5]
Total assets	41		34
Liabilities
Derivative Liability	4	[2],[5]	6	[2],[5]
Long-term debt, including current portion	0	[6]	0	[6]
Total liabilities	4		6
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities (current and long-term):
Investment securities	23	[1],[2],[3]	23	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	165	[2],[3],[4]	161	[2],[3],[4]
Derivatives:
Derivative assets	47	[2],[5]	15	[2],[5]
Total assets	235		199
Liabilities
Derivative Liability	61	[2],[5]	94	[2],[5]
Long-term debt, including current portion	19,866	[6]	18,735	[6]
Total liabilities	19,927		18,829
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Derivatives:
Derivative assets	268	[2],[5]	316	[2],[5]
Total assets	268		316
Liabilities
Derivative Liability	0	[2],[5]	0	[2],[5]
Long-term debt, including current portion	0	[6]	0	[6]
Total liabilities	0		0
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Derivative Liability	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Derivative Liability	60	[2],[5]	93	[2],[5]
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Derivative Liability	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Liabilities
Derivative Liability	4	[2],[5]	6	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Liabilities
Derivative Liability	1	[2],[5]	1	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Liabilities
Derivative Liability	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | U.S. core fixed income fund [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | U.S. core fixed income fund [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities (current and long-term):
Investment securities	23	[1],[2],[3]	23	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	52	[2],[3],[4]	52	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | U.S. core fixed income fund [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Money market funds [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities (current and long-term):
Investment securities	22	[1],[2],[3]	20	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	10	[2],[3],[4]	11	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Money market funds [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Money market funds [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Equity securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities (current and long-term):
Investment securities	3	[1],[2],[3]	3	[1],[2],[3]
Fair Value, Measurements, Recurring [Member] | Equity securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Fair Value, Measurements, Recurring [Member] | Equity securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities (current and long-term):
Investment securities	0	[1],[2],[3]	0	[1],[2],[3]
Fair Value, Measurements, Recurring [Member] | Government bonds and notes [Member] | Fair Value, Inputs, Level 1 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Government bonds and notes [Member] | Fair Value, Inputs, Level 2 [Member]
Legally restricted funds (long-term):
Legally restricted funds	39	[2],[3],[4]	39	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Government bonds and notes [Member] | Fair Value, Inputs, Level 3 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Government mortgage-backed securities [Member] | Fair Value, Inputs, Level 1 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Government mortgage-backed securities [Member] | Fair Value, Inputs, Level 2 [Member]
Legally restricted funds (long-term):
Legally restricted funds	29	[2],[3],[4]	25	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Government mortgage-backed securities [Member] | Fair Value, Inputs, Level 3 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Legally restricted funds (long-term):
Legally restricted funds	28	[2],[3],[4]	27	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member] | Fair Value, Inputs, Level 1 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member] | Fair Value, Inputs, Level 2 [Member]
Legally restricted funds (long-term):
Legally restricted funds	16	[2],[3],[4]	17	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member] | Fair Value, Inputs, Level 3 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member] | Fair Value, Inputs, Level 1 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Legally restricted funds (long-term):
Legally restricted funds	1	[2],[3],[4]	1	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member] | Fair Value, Inputs, Level 3 [Member]
Legally restricted funds (long-term):
Legally restricted funds	0	[2],[3],[4]	0	[2],[3],[4]
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives:
Derivative assets	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives:
Derivative assets	46	[2],[5]	15	[2],[5]
Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives:
Derivative assets	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Crude oil options [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives:
Derivative assets	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Crude oil options [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives:
Derivative assets	0	[2],[5]	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Crude oil options [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives:
Derivative assets	268	[2],[5]	316	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives:
Derivative assets	4	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives:
Derivative assets	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives:
Derivative assets	0	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper forward contracts [Member] | Fair Value, Inputs, Level 1 [Member]
Derivatives:
Derivative assets	2	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper forward contracts [Member] | Fair Value, Inputs, Level 2 [Member]
Derivatives:
Derivative assets	1	[2],[5]
Fair Value, Measurements, Recurring [Member] | Copper forward contracts [Member] | Fair Value, Inputs, Level 3 [Member]
Derivatives:
Derivative assets	0	[2],[5]
Deferred Option Premiums and Accrued Interest [Member]
Derivatives:
Derivative assets	159		210
Other Current Assets [Member]
Investment securities (current and long-term):
Escrow Deposit	115
Derivatives:
Derivative assets	270		316
Liabilities
Derivative Liability	0		0
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Investment securities (current and long-term):
Investment securities	48	[1],[2],[3]	46	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	175	[2],[3],[4]	172	[2],[3],[4]
Derivatives:
Derivative assets	321	[2],[5]	331	[2],[5]
Liabilities
Derivative Liability	65	[2],[5]	100	[2],[5]
Long-term debt, including current portion	20,312	[6]	18,849	[6]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member]
Liabilities
Derivative Liability	60	[2],[5]	93	[2],[5]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member]
Liabilities
Derivative Liability	5	[2],[5]	7	[2],[5]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | U.S. core fixed income fund [Member]
Investment securities (current and long-term):
Investment securities	23	[1],[2],[3]	23	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	52	[2],[3],[4]	52	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Money market funds [Member]
Investment securities (current and long-term):
Investment securities	22	[1],[2],[3]	20	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	10	[2],[3],[4]	11	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Equity securities [Member]
Investment securities (current and long-term):
Investment securities	3	[1],[2],[3]	3	[1],[2],[3]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Government bonds and notes [Member]
Legally restricted funds (long-term):
Legally restricted funds	39	[2],[3],[4]	39	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Government mortgage-backed securities [Member]
Legally restricted funds (long-term):
Legally restricted funds	29	[2],[3],[4]	25	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Legally restricted funds (long-term):
Legally restricted funds	28	[2],[3],[4]	27	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Legally restricted funds (long-term):
Legally restricted funds	16	[2],[3],[4]	17	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member]
Legally restricted funds (long-term):
Legally restricted funds	1	[2],[3],[4]	1	[2],[3],[4]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member]
Derivatives:
Derivative assets	46	[2],[5]	15	[2],[5]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Crude oil options [Member]
Derivatives:
Derivative assets	268	[2],[5]	316	[2],[5]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member]
Derivatives:
Derivative assets	4	[2],[5]
Reported Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper forward contracts [Member]
Derivatives:
Derivative assets	3	[2],[5]
Reported Value Measurement [Member] | Other Current Assets [Member] | Fair Value, Measurements, Recurring [Member] | Time Deposits [Member]
Investment securities (current and long-term):
Investment securities	18
Reported Value Measurement [Member] | Other Assets [Member] | Fair Value, Measurements, Recurring [Member] | Time Deposits [Member]
Investment securities (current and long-term):
Investment securities			17
Liabilities
Escrow Deposit Disbursements Related to Property Acquisition	116		115
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member]
Investment securities (current and long-term):
Investment securities	48	[1],[2],[3]	46	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	175	[2],[3],[4]	172	[2],[3],[4]
Derivatives:
Derivative assets	321	[2],[5]	331	[2],[5]
Total assets	544		549
Liabilities
Derivative Liability	65	[2],[5]	100	[2],[5]
Long-term debt, including current portion	19,866	[6]	18,735	[6]
Total liabilities	19,931		18,835
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member]
Liabilities
Derivative Liability	60	[2],[5]	93	[2],[5]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member]
Liabilities
Derivative Liability	5	[2],[5]	7	[2],[5]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | U.S. core fixed income fund [Member]
Investment securities (current and long-term):
Investment securities	23	[1],[2],[3]	23	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	52	[2],[3],[4]	52	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Money market funds [Member]
Investment securities (current and long-term):
Investment securities	22	[1],[2],[3]	20	[1],[2],[3]
Legally restricted funds (long-term):
Legally restricted funds	10	[2],[3],[4]	11	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Equity securities [Member]
Investment securities (current and long-term):
Investment securities	3	[1],[2],[3]	3	[1],[2],[3]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Government bonds and notes [Member]
Legally restricted funds (long-term):
Legally restricted funds	39	[2],[3],[4]	39	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Government mortgage-backed securities [Member]
Legally restricted funds (long-term):
Legally restricted funds	29	[2],[3],[4]	25	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Corporate bonds [Member]
Legally restricted funds (long-term):
Legally restricted funds	28	[2],[3],[4]	27	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Asset-backed securities [Member]
Legally restricted funds (long-term):
Legally restricted funds	16	[2],[3],[4]	17	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Municipal bonds [Member]
Legally restricted funds (long-term):
Legally restricted funds	1	[2],[3],[4]	1	[2],[3],[4]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Embedded derivatives in provisional sales/purchases contracts [Member]
Derivatives:
Derivative assets	46	[2],[5]	15	[2],[5]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Crude oil options [Member]
Derivatives:
Derivative assets	268	[2],[5]	316	[2],[5]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper futures and swap contracts [Member]
Derivatives:
Derivative assets	4	[2],[5]
Estimate of Fair Value Measurement [Member] | Fair Value, Measurements, Recurring [Member] | Copper forward contracts [Member]
Derivatives:
Derivative assets	$ 3	[2],[5]

[1] Excludes time deposits of $116 million (which approximated fair value) included in other assets at March 31, 2015, and $115 million at December 31, 2014, associated with an assurance bond to support PT Freeport Indonesia's (PT-FI) commitment for smelter development in Indonesia.

[2] Recorded at fair value.

[3] Current portion included in other current assets and long-term portion included in other assets.

[4] Excludes time deposits of $18 million (which approximated fair value) included in other current assets at March 31, 2015, and $17 million at December 31, 2014, associated with a customs audit assessment and a reclamation guarantee at PT-FI.

[5] Refer to Note 6 for further discussion and balance sheet classifications. Crude oil options are net of $159 million at March 31, 2015, and $210 million at December 31, 2014, for deferred premiums and accrued interest.

[6] Recorded at cost except for debt assumed in acquisitions, which were recorded at fair value at the respective acquisition dates.