Financial Instruments (Unaudited) (Details) (Commodity Contract [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Fair Value Hedging [Member] | Amounts recorded in Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative financial instruments	$ (12)		$ 18
Hedged item	12		(18)
Matured derivative financial instruments	(2)		10
Derivatives not designated as hedging instruments [Member] | Atlantic Copper [Member] | Embedded derivatives in provisional sales contracts [Member] | Amounts recorded in Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses)	(83)	[1]	184	[1]
Derivatives not designated as hedging instruments [Member] | Atlantic Copper [Member] | Copper forward contracts [Member] | Amounts recorded in Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses)	$ 3	[2]	$ 11	[2]

[1] Amounts recorded in revenues.

[2] Amounts recorded in cost of sales as production and delivery costs.