The average market price for a group of price risk forward or futures contracts, such as gas futures contracts.

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- Definition

Amount of gain (loss) from the increase (decrease) in fair value of derivative and nonderivative instruments designated as fair value hedging instruments recognized in the income statement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986

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- Definition

Amount of the increase (decrease) in fair value of the hedged item in a fair value hedge recognized in the income statement.

+ References

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- Definition

The average forward price on the group of price risk forward or futures contracts, such as gas futures contracts.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5618551-113959

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Nominal mass used to calculate payments on a derivative instrument.

+ References

No definition available.

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- Definition

Net Increase or Decrease in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 15
-URI http://asc.fasb.org/subtopic&trid=2229187

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Financial Instruments (Unrealized gains losses) (Details) oz in Thousands, lb in Millions, $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2018 lb $ / lb $ / lb $ / oz	Sep. 30, 2018 lb oz $ / lb $ / lb $ / oz	Sep. 30, 2018 USD ($) $ / lb $ / lb $ / oz	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) $ / lb $ / lb $ / oz	Sep. 30, 2017 USD ($)
Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net \| $			$ (118)	$ 137	$ (279)	$ 297
Commodity Contract [Member]
Unrealized gains (losses):
Derivative financial instruments \| $			7	0	(12)	(1)
Hedged item – firm sales commitments \| $			(7)	0	12	1
Realized gains (losses):
Matured derivative financial instruments \| $			$ (19)	12	$ (17)	21
Commodity Contract [Member] \| Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb	78
Derivative, Average Forward Price	2.81	2.81	2.81		2.81
Copper Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb		31
Derivative, Average Forward Price	2.73	2.73	2.73		2.73
Copper Forward Contracts [Member] \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Cost of Sales
Realized gains (losses):
Matured derivative financial instruments \| $			$ 9	(9)	$ 17	(14)
Copper \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net \| $			$ (93)	133	$ (242)	275
Copper \| Short [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb		567
Derivative, Average Forward Price	2.82	2.82	2.82		2.82
Realized gains (losses):
Derivative Average Market Price	2.84	2.84	2.84		2.84
Copper \| Long [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb		125
Derivative, Average Forward Price	2.78	2.78	2.78		2.78
Realized gains (losses):
Derivative Average Market Price	2.84	2.84	2.84		2.84
Gold \| Short [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| oz		375
Derivative, Average Forward Price \| $ / oz	1,201.40	1,201.40	1,201.40		1,201.40
Realized gains (losses):
Derivative Average Market Price \| $ / oz	1,188.75	1,188.75	1,188.75		1,188.75
gold and other [Member] \| Not Designated as Hedging Instrument [Member] \| Amounts recorded in Sales [Member]
Realized gains (losses):
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net \| $			$ (25)	$ 4	$ (37)	$ 22
Cobalt \| Long [Member] \| Embedded Derivative Financial Instruments [Member] \| Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount, Mass \| lb		7
Derivative, Average Forward Price	23.80	23.80	23.80		23.80
Realized gains (losses):
Derivative Average Market Price	22.14	22.14	22.14		22.14