STOCK-BASED EMPLOYEE COMPENSATION

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Stock-based compensation expense included in "Personnel" expenses in the Unaudited Consolidated Statements of Operations was $6 million and $74 million for the three months ended March 31, 2020 and 2019, respectively.

Stock-based compensation expense related to performance share units, restricted stock units and stock options is recognized based on fair value on a straight-line basis over the respective requisite service periods and forfeitures are accounted for when they occur. The fair value on the grant date of performance share units and restricted stock units is determined based on the number of units granted and the quoted price of the Company's common stock. The fair value of employee stock options assumed in acquisitions was determined using the Black-Scholes model and the market value of the Company's common stock at the respective acquisition dates.

The Company records stock-based compensation expense for performance-based awards using its estimate of the probable outcome at the end of the performance period (i.e., the estimated performance against the performance targets). The Company periodically adjusts the cumulative stock-based compensation expense recorded when the probable outcome for these performance-based awards is updated based upon changes in actual and forecasted operating results. For the performance share units outstanding at March 31, 2020, due to the impact of the COVID-19 pandemic (see Note 1), there is a significant decline in the estimated performance over the performance periods against the performance targets. At March 31, 2020, there was a significant reduction in the number of shares that were probable to be issued as compared to December 31, 2019. As a result, in the three months ended March 31, 2020, the Company recognized a reduction in stock-based compensation expense of $73 million, which is included in "Personnel" expense in the Unaudited Consolidated Statement of Operations.

Restricted stock units granted by the Company during the three months ended March 31, 2020 had aggregate grant-date fair values of $265 million. Restricted stock units and performance share units that vested during the three months ended March 31, 2020 had aggregate fair values at vesting of $319 million. At March 31, 2020, there was $541 million of estimated total future stock-based compensation expense related to unvested share-based awards to be recognized over a weighted-average period of 2.3 years.

Restricted Stock Units

The Company makes broad-based grants of restricted stock units that generally vest during a period of one- to three-years, subject to certain exceptions for terminations other than for "cause," for "good reason" or on account of death or disability.

The following table summarizes the activity of restricted stock units for employees and non-employee directors during the three months ended March 31, 2020:



Restricted Stock Units	Shares		Weighted-average Grant-date Fair Value Per Share
Unvested at December 31, 2019	256,745			$	1,801

Granted	152,832			$	1,732
Vested	(109,595	)		$	1,808
Forfeited	(5,971	)		$	1,805
Unvested at March 31, 2020	294,011			$	1,762

Performance Share Units

The Company grants performance share units to executives and certain other employees, which generally vest at the end of a three-year period, subject to certain exceptions for terminations other than for "cause," for "good reason" or on account of death or disability. Performance share units are payable in shares of the Company's common stock upon vesting. The number of shares which ultimately will vest depends on achieving certain performance metrics by the end of the performance period, assuming there is no accelerated vesting for, among other things, a termination of employment under certain circumstances.

The following table summarizes the activity of performance share units for employees during the three months ended March 31, 2020:



Performance Share Units	Shares		Weighted-average Grant-date Fair Value Per Share
Unvested at December 31, 2019	216,083			$	1,835

Vested	(80,266	)		$	1,737
Performance Shares Adjustment *	(58,427	)		$	1,957
Forfeited	(2,989	)		$	1,834
Unvested at March 31, 2020	74,401			$	1,841

* Probable outcome for these performance-based awards is updated based upon changes in actual and forecasted operating results.

No performance share units were granted during the three months ended March 31, 2020. The following table summarizes the estimated vesting, as of March 31, 2020, of performance share units granted in 2019 and 2018, net of forfeiture and vesting since the respective grant dates:

Stock Options

All outstanding employee stock options were assumed in acquisitions, and generally have a term of 10 years from the grant date. The following table summarizes the activity for stock options during the three months ended March 31, 2020:



Employee Stock Options	Number of Shares		Weighted-average Exercise Price			Aggregate Intrinsic Value (in millions)			Weighted-average Remaining Contractual Term (in years)
Balance, December 31, 2019	15,122			$	484		$	24	2.6
Exercised	(100	)		$	334
Balance, March 31, 2020	15,022			$	485		$	13	2.4
Vested and exercisable at March 31, 2020	15,022			$	485		$	13	2.4

Performance Share Units, by grant year

Shares probable to be issued

Shares not subject to the achievement of minimum performance thresholds

Shares that could be issued if maximum performance thresholds are met