EXHIBIT 12.1

Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends

	Nine months Ended September 30,		Year Ended December 31,					Four Months Ended December 31,			Eight Months Ended August 31,		Year Ended December 31,
(in millions)	2016		2015		2014			2013			2013		2012			2011
Income (loss) from continuing operations before income taxes	$	50	$	2	$	(49	)	$	(55	)	$	2,406	$	(1,610	)	$	(757	)
Adjustments:
Interest expense		48		63		62			22			106		139			138
Interest component of rental expense (1)		7		10		13			5			12		20			25
Amortization of capitalized interest		—		—		—			—			—		2			2
Earnings available for fixed charges	$	105	$	75	$	26		$	(28	)	$	2,524	$	(1,449	)	$	(592	)
Fixed charges:
Interest expense		48		63		62			22			106		139			138
Interest component of rental expense(1)		7		10		13			5			12		20			25
Capitalized interest		—		2		3			—			—		1			1
Total fixed charges	$	55	$	75	$	78		$	27		$	118	$	160		$	164
Ratio of earnings to combined fixed charges and preferred stock dividends		1.9		1.0		*			**			21.4		***			****

(1) Interest component of rental expense is estimated to equal 1/3 of such expense, which is considered a reasonable approximation of the interest factor.

* Earnings for the year ended December 31, 2014 were inadequate to cover fixed charges. The coverage deficiency was $52 million.

** Earnings for the four months ended December 31, 2013 were inadequate to cover fixed charges. The coverage deficiency was $55 million.

*** Earnings for the year ended December 31, 2012 were inadequate to cover fixed charges. The coverage deficiency was $1,609 million.

**** Earnings for the year ended December 31, 2011 were inadequate to cover fixed charges. The coverage deficiency was $756 million.

For the periods indicated above, we had no outstanding shares of preferred stock with required dividend payments.