Under our 2016 Incentive Compensation Plan and previously under our 2007 Incentive Compensation Plan (collectively, Incentive Compensation Plans), awards may be granted to employees and other key individuals who perform services for us and our participating subsidiaries. These awards may be in the form of stock options, restricted stock units or awards (collectively referred to as RSUs), portfolio grants (PGs) or other incentives or similar awards designed to meet the requirements of non-U.S. jurisdictions.

For our Incentive Compensation Plans, there were a total of 9 million, 12 million and 14 million common shares unissued and available for grant as of December 31, 2019, 2018, and 2017, respectively, as authorized by our Board of Directors and shareholders. We generally issue new common shares upon exercise of options and vesting of RSUs.

Stock-based compensation expense recognized in Salaries and employee benefits in the Consolidated Statements of Income was $280 million, $288 million and $283 million in 2019, 2018, and 2017, respectively, with corresponding income tax benefits of $67 million, $69 million, and $102 million in those respective periods.


	Stock Options				Service-Based RSUs					Service and Performance-Based RSUs
(Shares in thousands)	Shares	Weighted-Average Exercise Price		Shares	Weighted- Average Grant Price		Shares	Weighted- Average Grant Price
Outstanding as of December 31, 2018	5,484	$	64.73	2,544	$	80.15	4,022	$	74.22
Granted	408	101.43		1,041	103.93		1,358	90.34
Exercised/vested	(1,626)	51.92		(1,001)	76.07		(1,819)	58.28
Forfeited	(94)	92.19		(172)	89.79		(169)	93.74
Expired	—	—		—	—		—	—
Outstanding as of December 31, 2019	4,172	72.70		2,412	$	91.42	3,392	$	88.25
Options vested and expected to vest as of December 31, 2019	4,171	72.70
Options exercisable as of December 31, 2019	2,357	$	61.15

The cost of employee stock awards granted in exchange for employee services is generally recognized ratably based on the grant-date fair value of the award, net of expected forfeitures, over the vesting period. The vesting period is the shorter of the vesting schedule as defined in each award agreement or the date an individual will become eligible to retire. Retirement eligibility is dependent upon age and/or years of service.

Each stock option has an exercise price equal to the market price of our common stock on the date of grant. Stock options generally vest on the third anniversary of the grant date and have a contractual term of 10 years from the date of grant.

The weighted-average remaining contractual life and the aggregate intrinsic value (the amount by which the fair value of our stock price exceeds the exercise price of the option) of the stock options outstanding, exercisable, and vested and expected to vest as of December 31, 2019, were as follows:


	Outstanding		Exercisable		Vested and Expected to Vest
Weighted-average remaining contractual life (in years)	5.3		4.0		5.3
Aggregate intrinsic value (millions)	$	216	$	149	$	216

As of December 31, 2019, there was $7 million of total unrecognized compensation cost related to unvested options, which will be recognized ratably over the weighted-average remaining vesting period of 1.2 years.

The fair value of each option is estimated on the date of grant using a Black-Scholes-Merton option-pricing model. The following weighted-average assumptions were used for options granted in 2019, 2018 and 2017:


	2019			2018			2017
Dividend yield	1.5		%	1.4		%	1.8		%
Expected volatility^(a)	24		%	22		%	24		%
Risk-free interest rate	2.6		%	2.7		%	2.3		%
Expected life of stock option (in years)^(b)	7.1			7.1			6.9
Weighted-average fair value per option	$	23.38		$	23.17		$	18.18

On October 31, 2017, certain senior executives were granted stock options with a term of seven years, and include a three-year service condition, as well as performance and market conditions. Therefore, the fair values of these options were estimated at the grant date using a Monte Carlo valuation model with the following assumptions:


	October 31, 2017
Dividend yield	1.58		%
Expected volatility^(a)	21.41		%
Risk-free interest rate	2.26		%
Expected life of stock option (in years)	7
Fair value per option	$	19.18

For stock options that were exercised during 2019, 2018 and 2017, the intrinsic value, based upon the fair value of our stock price at the date the options were exercised, was $104 million, $104 million and $197 million, respectively; cash received from the exercise of stock options was $84 million, $87 million and $130 million during those respective periods. The income tax benefit recognized in the Consolidated Statements of Income related to stock option exercises was $18 million, $18 million and $59 million in 2019, 2018 and 2017, respectively.

We grant RSUs that contain either a) service conditions or b) both service and performance conditions. RSUs containing only service conditions generally vest 25 percent per year beginning with the first anniversary of the grant date. RSUs containing both service and performance conditions generally vest on the third anniversary of the grant date, and the number of shares earned depends on the achievement of predetermined Company metrics. All RSU holders receive non-forfeitable dividends or dividend equivalents.

We added a relative total shareholder return (r-TSR) modifier to the performance-based RSUs that were granted in 2019, so that our actual shareholder return relative to a competitive peer group is one of the performance conditions that determines the number of shares ultimately granted upon vesting.

The fair value of RSUs that do not include the r-TSR modifier, including those that contain only service conditions, is measured using our stock price on the grant date. The fair value of service and performance-based RSUs that include the r-TSR modifier is determined using a Monte Carlo valuation model with the following weighted-average assumptions:

As of December 31, 2019, there was $195 million of total unrecognized compensation cost related to non-vested RSUs, which will be recognized ratably over the weighted-average remaining vesting period of 2.1 years.

For RSUs vested during 2019, 2018 and 2017, the total fair value, based upon our stock price at the date the RSUs vested, was $286 million, $239 million and $180 million, respectively.

In 2018 and 2017, certain employees were awarded PGs and other incentive awards that can be settled with cash or equity shares at our discretion, and final Compensation and Benefits Committee payout approval; beginning in 2019, we discontinued granting PGs. These awards earn value based on performance, market and/or service conditions, and vest over periods of one to three years.

PGs and other incentive awards are generally settled with cash and thus are classified as liabilities; therefore, the fair value is determined at the date of grant and remeasured quarterly as part of compensation expense over the vesting period. Cash paid upon vesting of these awards in 2019, 2018 and 2017 was $81 million, $56 million and $48 million, respectively.