Derivative Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2016

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of effect of derivatives in our consolidated statements of operations

The effect of derivatives in our consolidated statements of operations is shown in the table below:



	Gain (loss) in income
		Year ended December 31,
	Location	2016			2015			2014
		(in millions)
Natural gas derivatives	Cost of sales	$	260		$	(176	)	$	(79	)
Foreign exchange contracts	Other operating—net	—			22			(44		)
Unrealized gains (losses) recognized in income		260			(154		)	(123		)
Realized (losses) gains		(133		)	(114		)	64
Net derivative gains (losses)		$	127		$	(268	)	$	(59	)

Schedule of fair values of derivatives in our consolidated balance sheet

The fair values of derivatives on our consolidated balance sheets are shown below. As of December 31, 2016 and 2015, none of our derivative instruments were designated as hedging instruments. See Note 9—Fair Value Measurements for additional information on derivative fair values.



	Asset Derivatives					Liability Derivatives
	Balance Sheet Location	December 31,				Balance Sheet Location	December 31,
	Balance Sheet Location	2016		2015		Balance Sheet Location	2016			2015
		(in millions)					(in millions)
Natural gas derivatives	Other current assets	$	52	$	—	Other current liabilities	$	—		$	(130	)
Natural gas derivatives	Other assets	4		—		Other liabilities	(6		)	(81		)
Total derivatives		$	56	$	—		$	(6	)	$	(211	)

Schedule of amounts relevant to offsetting of derivative assets

The following table presents amounts relevant to offsetting of our derivative assets and liabilities as of December 31, 2016 and 2015:



	Amounts presented in consolidated balance sheets⁽¹⁾			Gross amounts not offset in consolidated balance sheets
	Amounts presented in consolidated balance sheets⁽¹⁾			Financial instruments		Cash collateral received (pledged)		Net amount
	(in millions)
December 31, 2016
Total derivative assets	$	56		$	6	$	—	$	50
Total derivative liabilities	6			6		—		—
Net derivative assets	$	50		$	—	$	—	$	50
December 31, 2015
Total derivative assets	$	—		$	—	$	—	$	—
Total derivative liabilities	211			—		—		211
Net derivative liabilities	$	(211	)	$	—	$	—	$	(211	)

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⁽¹⁾	We report the fair values of our derivative assets and liabilities on a gross basis on our consolidated balance sheets. As a result, the gross amounts recognized and net amounts presented herein are the same.

Schedule of amounts relevant to offsetting of derivative liabilities

The following table presents amounts relevant to offsetting of our derivative assets and liabilities as of December 31, 2016 and 2015:



	Amounts presented in consolidated balance sheets⁽¹⁾			Gross amounts not offset in consolidated balance sheets
	Amounts presented in consolidated balance sheets⁽¹⁾			Financial instruments		Cash collateral received (pledged)		Net amount
	(in millions)
December 31, 2016
Total derivative assets	$	56		$	6	$	—	$	50
Total derivative liabilities	6			6		—		—
Net derivative assets	$	50		$	—	$	—	$	50
December 31, 2015
Total derivative assets	$	—		$	—	$	—	$	—
Total derivative liabilities	211			—		—		211
Net derivative liabilities	$	(211	)	$	—	$	—	$	(211	)

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⁽¹⁾	We report the fair values of our derivative assets and liabilities on a gross basis on our consolidated balance sheets. As a result, the gross amounts recognized and net amounts presented herein are the same.