Our long-term debt consisted of the following as of December 31, 2016 and 2015:



	December 31, 2016						December 31, 2015
	Principal Amount			Carrying Amount			Principal Amount			Carrying Amount
	($ in millions)
Term loan due 2021	$	1,500		$	1,500		$	—		$	—
3.25% senior notes due 2016	—			—			381			381
6.25% euro-denominated senior notes due 2017^(a)	258			258			329			329
6.5% senior notes due 2017	134			134			453			453
7.25% senior notes due 2018	64			64			538			538
Floating rate senior notes due 2019	380			380			1,104			1,104
6.625% senior notes due 2020	780			780			822			822
6.875% senior notes due 2020	279			279			304			304
6.125% senior notes due 2021	550			550			589			589
5.375% senior notes due 2021	270			270			286			286
4.875% senior notes due 2022	451			451			639			639
8.00% senior secured second lien notes due 2022^(b)	2,419			3,409			2,425			3,584
5.75% senior notes due 2023	338			338			384			384
8.00% senior notes due 2025	1,000			1,000			—			—
5.5% convertible senior notes due 2026^(c)(e)	1,250			811			—			—
2.75% contingent convertible senior notes due 2035^(d)	2			2			2			2
2.5% contingent convertible senior notes due 2037^(d)(e)	114			112			1,110			1,027
2.25% contingent convertible senior notes due 2038^(d)(e)	200			180			340			290
Revolving credit facility	—			—			—			—
Debt issuance costs	—			(64		)	—			(43		)
Discount on senior notes	—			(16		)	—			(4		)
Interest rate derivatives^(f)	—			3			—			7
Total debt, net	9,989			10,441			9,706			10,692
Less current maturities of long-term debt, net^(g)	(506		)	(503		)	(381		)	(381		)
Total long-term debt, net	$	9,483		$	9,938		$	9,325		$	10,311

___________________________________________


(a)	The principal and carrying amounts shown are based on the exchange rate of $1.0517 to €1.00 and $1.0862 to €1.00 as of December 31, 2016 and 2015, respectively. See Foreign Currency Derivatives in Note 11 for information on our related foreign currency derivatives.


(b)	The carrying amounts as of December 31, 2016 and 2015, include premium amounts of $990 million and $1.159 billion, respectively, associated with a troubled debt restructuring. The premium is being amortized based on an effective yield method.


(c)	The conversion and redemption provisions of our convertible senior notes are as follows:

Optional Conversion by Holders. At the holder’s option, prior to maturity under certain circumstances, the notes are convertible into cash, our common stock, or a combination of cash and common stock, at our election. One triggering circumstance is when the price of our common stock exceeds a threshold amount during a specified period in a fiscal quarter, beginning with the first quarter of 2017. Convertibility based on common stock price is measured quarterly. The notes are also convertible, at the holder’s option, during specified five-day periods if the trading price of the notes is below certain levels determined by reference to the trading price of our common stock. The notes were not convertible under this provision during the year ended December 31, 2016. Upon conversion of a convertible senior note, the holder will receive cash, common stock or a combination of cash and common stock, at our election, according to the conversion rate specified in the indenture.

The common stock price conversion threshold amount for the convertible senior notes is 130% of the conversion price.

Optional Redemption by the Company. We may redeem the convertible senior notes for cash on or after September 15, 2019 if the price of our common stock exceeds 130% of the conversion price during a specified period at a redemption price of 100% of the principal amount of the notes.


(d)	The repurchase, conversion, contingent interest and redemption provisions of our contingent convertible senior notes are as follows:

Holders’ Demand Repurchase Rights. The holders of our contingent convertible senior notes may require us to repurchase, in cash, all or a portion of their notes at 100% of the principal amount of the notes on any of four dates that are five, ten, fifteen and twenty years before the maturity date.

Optional Conversion by Holders. At the holder’s option, prior to maturity under certain circumstances, the notes are convertible into cash and, if applicable, our common stock using a net share settlement process. One triggering circumstance is when the price of our common stock exceeds a threshold amount during a specified period within a fiscal quarter. Convertibility based on common stock price is measured quarterly. During the specified period in the fourth quarter of 2016, the price of our common stock was below the threshold level for each series of the contingent convertible senior notes and, as a result, the holders do not have the option to convert their notes into cash or common stock in the first quarter of 2017 under this provision.

The notes are also convertible, at the holder’s option, during specified five-day periods if the trading price of the notes is below certain levels determined by reference to the trading price of our common stock. The notes were not convertible under this provision during the years ended December 31, 2016, 2015 and 2014. In general, upon conversion of a contingent convertible senior note, the holder will receive cash equal to the principal amount of the note and common stock for the note’s conversion value in excess of the principal amount.

Contingent Interest. We will pay contingent interest on the contingent convertible senior notes after they have been outstanding at least ten years during certain periods if the average trading price of the notes exceeds the threshold defined in the indenture.

The holders’ demand repurchase dates, the common stock price conversion threshold amounts (as adjusted to give effect to cash dividends on our common stock) and the ending date of the first six-month period in which contingent interest may be payable for the contingent convertible senior notes are as follows:



Contingent Convertible Senior Notes	Holders' Demand Repurchase Dates	Common Stock Price Conversion Thresholds		Contingent Interest First Payable (if applicable)
2.75% due 2035	November 15, 2020, 2025, 2030	$	45.02	May 14, 2016
2.5% due 2037	May 15, 2017, 2022, 2027, 2032	$	59.44	November 14, 2017
2.25% due 2038	December 15, 2018, 2023, 2028, 2033	$	100.20	June 14, 2019

Optional Redemption by the Company. We may redeem the contingent convertible senior notes once they have been outstanding for ten years at a redemption price of 100% of the principal amount of the notes, payable in cash. In addition, we may redeem our 2.75% Contingent Convertible Senior Notes due 2035 at any time.


(e)	The carrying amounts as of December 31, 2016 and 2015 are reflected net of discounts of $461 million and $133 million, respectively, associated with the equity component of our convertible and contingent convertible senior notes. This amount is being amortized based on an effective yield method through the first demand repurchase date as applicable.


(f)	See Interest Rate Derivatives in Note 11 for further discussion related to these instruments.

(g)

As of December 31, 2016, current maturities of long-term debt, net includes our 6.25% Euro-denominated Senior Notes due 2017, 6.5% Senior Notes due 2017 and our 2.5% Contingent Convertible Senior Notes due 2037 (2037 Notes). As discussed in footnote (b) above, the holders of our 2037 Notes could exercise their individual demand repurchase rights on May 15, 2017, which would require us to repurchase all or a portion of the principal amount of the notes. As of December 31, 2016, there was $2 million associated with the equity component of the 2037 Notes.