SHARE-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of the components and classification of share-based compensation expense

The components and classification of share-based compensation expense related to stock options and RSUs for the years ended December 31, 2018, 2017 and 2016 were as follows:

(in millions)	2018		2017		2016
Stock options	$	23	$	18	$	16
RSUs	64		69		149
Share-based compensation expense	$	87	$	87	$	165
Research and development expenses	$	9	$	8	$	7
Selling, general and administrative expenses	78		79		158
Share-based compensation expense	$	87	$	87	$	165

Schedule of weighted-average assumption as of the date of grant using the Black Scholes option-pricing model

The fair values of all stock options granted for the years ended December 31, 2018, 2017 and 2016 were estimated as of the date of grant using the Black-Scholes option-pricing model with the following weighted-average assumptions:

	2018		2017		2016
Expected stock option life (years)	3.0		3.0		3.3
Expected volatility	54.0	%	67.3	%	75.0	%
Risk-free interest rate	2.7	%	1.8	%	1.1	%
Expected dividend yield	—	%	—	%	—	%

Summary of stock option activity

The following table summarizes stock option activity during 2018:

(in millions, except per share amounts)	Options		Weighted- Average Exercise Price Per Share		Weighted- Average Remaining Contractual Term (Years)	Aggregate Intrinsic Value
Outstanding, January 1, 2018	4.5		$	34.65
Granted	2.1		$	15.52
Exercised	(0.2	)	$	16.73
Expired or forfeited	(0.5	)	$	37.47
Outstanding, December 31, 2018	5.9		$	27.88	7.9	$	11
Vested and expected to vest, December 31, 2018	5.5		$	28.61	7.9	$	10
Vested and exercisable, December 31, 2018	2.2		$	43.85	6.8	$	2

Summary of non-vested time-based RSU activity

The following table summarizes non-vested time-based RSU activity during 2018:

(in millions, except per share amounts)	Time-Based RSUs		Weighted- Average Grant-Date Fair Value Per Share
Non-vested, January 1, 2018	4.7		$	19.09
Granted	3.0		$	17.59
Vested	(1.5	)	$	20.19
Forfeited	(0.4	)	$	16.48
Non-vested, December 31, 2018	5.8		$	18.29

Schedule of assumptions used to calculate the fair values of performance-based RSUs

The fair values of performance-based RSUs granted during 2018, 2017 and 2016 were estimated with the following assumptions:

	2018	2017	2016
Contractual term (years)	3.0	3.0	3.0 - 4.0
Expected Company share volatility	54.2%	67.2% - 77.2%	78.2% - 81.4%
Risk-free interest rate	2.7%	1.7% - 1.8%	1.0% - 1.2%

Summary of non-vested performance-based RSU activity

The following table summarizes non-vested performance-based RSU activity during 2018:

(in millions, except per share amounts)	Performance-based RSUs		Weighted- Average Grant-Date Fair Value Per Share
Non-vested, January 1, 2018	1.8		$	48.55
Granted	0.9		$	24.44
Vested	(0.1	)	$	247.04
Forfeited	(1.1	)	$	39.63
Non-vested, December 31, 2018	1.5		$	34.06