Subsequent Events (Unaudited) (Details) (PT Freeport Indonesia [Member], USD $) In Millions, unless otherwise specified	6 Months Ended	3 Months Ended		3 Months Ended
	Jun. 30, 2014	Sep. 30, 2014 Subsequent Event [Member]	Jul. 25, 2014 Subsequent Event [Member]	Sep. 30, 2014 Maximum [Member] Subsequent Event [Member]	Sep. 30, 2014 Minimum [Member] Subsequent Event [Member]	Sep. 30, 2014 Stage 1 [Member] Subsequent Event [Member]	Sep. 30, 2014 Stage 2 [Member] Subsequent Event [Member]	Sep. 30, 2014 Stage 3 [Member] Subsequent Event [Member]
Subsequent Event [Line Items]
Effective Date, Memorandum of Understanding with Foreign Government		Jul. 25, 2014
Expiration Date, Contract of Work		Dec. 31, 2021
Percent Of Undivided Interest Owned By Third Party			30.00%
Incremental Percent of Undivided Interest Owned by Third Party			20.64%
Date, Contract of Work Extension				Dec. 31, 2041	Jan. 01, 2022
Contract of Work Negotiations, Term		0 years 6 months
Assurance Bond, Smelter Development		$ 115
Copper Royalty Rate	3.50%	4.00%
Gold Royalty Rate	1.00%	3.75%
Progressive Export Duty on Copper Concentrates, Percent						7.50%	5.00%	0.00%
Smelter Development Progress, Percent							7.50%	30.00%