Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

Share-based Payment Arrangement [Abstract]

Stock Based Compensation Activity

The activity related to RSUs consisted of (in thousands of shares):

			Number of Shares	Weighted Average Grant Date Fair Value		Weighted Average Remaining Contractual Term (years)	Aggregate Intrinsic Value (in millions)
Time-based RSUs
	Outstanding at January 1, 2020		847	$	36.99
		Granted (a)	798	23.14
		Vested (b)	(420)	37.82
		Forfeited	(81)	32.90
	Outstanding and expected to vest at September 30, 2020 (c)		1,144	$	27.31	1.2	$	30
Performance-based and market-based RSUs
	Outstanding at January 1, 2020		1,061	$	38.89
		Granted (a)	553	21.06
		Vested (b)	(73)	36.64
		Forfeited	(424)	35.15
	Outstanding at September 30, 2020		1,117	$	31.64	1.7	$	29
	Outstanding and expected to vest at September 30, 2020 (c)		38	$	20.70	2.7	$	1

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(a)Reflects the maximum number of stock units assuming achievement of all performance-, market- and time-vesting criteria and does not include those for non-employee directors. The weighted-average fair value of time-based RSUs and performance-based and market-based RSUs granted during the nine months ended September 30, 2019 was $34.17 and $34.56, respectively.

(b)The total fair value of RSUs vested during September 30, 2020 and 2019 was $19 million and $18 million, respectively.

(c)Aggregate unrecognized compensation expense related to time-based RSUs and performance-based and market-based RSUs amounted to $23 million and will be recognized over a weighted average vesting period of 1.3 years.