Financial Instruments (Unaudited) (Details) - Commodity Contract [Member] - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value Hedging [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative financial instruments		$ 1	$ (2)	$ 11	$ 0
Hedged item – firm sales commitments		(1)	2	(11)	0
Matured derivative financial instruments		0	(12)	(8)	(23)
Derivatives not designated as hedging instruments [Member] | Embedded derivatives in provisional sales contracts [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses)	[1]	12	(155)	88	(299)
Derivatives not designated as hedging instruments [Member] | Copper Forward Contracts [Member] | Cost of Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses)	[2]	(1)	(8)	4	(15)
Derivatives not designated as hedging instruments [Member] | Plains Exploration & Production Company [Member] | Crude Oil Options [Member] | Sales [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Realized and unrealized gains (losses)	[1]	$ 0	$ 29	$ 0	$ 87

[1] Amounts recorded in revenues.

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